Sunday, July 28, 2019

#197 - Tuesday, July 9, 2019 - Shooting with an Astro-DSLR

I managed once again to sleep in until 12:45 PM, and thank goodness!  I was starting to feel more adjusted to the altitude, and all three of us felt ready to go do some daytime exploring.  So I copied last night's data off of my memory cards, drank a hearty cup of coffee, and we left at 2:30 PM to go to dome sightseeing.

Our first stop was the Valle de la Luna, or "Valley of the Moon," but they only allow car entry between 8 AM and 1 PM, so we missed our chance.  Try again tomorrow...so instead we set our GPS for one of the sites in the salt flats, Salar de Atacama.  On the highway, we crossed the line of the Tropic of Capricorn!


Salar de Atacama was both the name of the general area, and supposedly a particular lagoon in the salt flats.  Unlike salt flats in other parts of the world, the one here in the Atacama Desert was not really that flat.  Well, the landscape was flat, but the salt formed stalagmites that stuck up out of the ground!  We pulled off to give it a closer look, and it was extremely hard stuff.  The salt chunks were also very sharp -- I was glad I had my hiking boots on with Vibram soles!  It also sounded hollow in places.  John used his Leatherman and some other tools he had in his pockets to bang on the crystalline structures, and with the different tones, he was making some music!  It was very cool and also very strange.


We wound up not finding a particular location or lagoon of Salar de Atacama, so we drove back northward to try Laguna Cejar.  But my phone's GPS said we wouldn't get there till 6:30 -- after sunset.  So we just drove back to the Atacama Lodge instead.  A day of bad luck!  But the drive was gorgeous, so there's that at least.  There were rocks strewn everywhere from volcanic eruptions, and there were some places where the road was washed out due to an earthquake re-routing a stream and launching all kinds of water down the mountain.  We also passed by the entrance to the radio telescope array ALMA, and we could see the workshop from the road.


Once we got back to the lodge, I went and found Alain to ask for help re-polar-aligning my Sky-Watcher Star Adventurer again once it got dark, and to get a status update on the Sky-Watcher AZEQ6 mount I was supposed to be borrowing, but it had quit working.  He said since he couldn't fix it right away, I could instead borrow an astro-modified Sony a7s with a Rokinon 135mm f/2.8 lens!  I was so all over that.  Astro-modified means that a standard DSLR camera has had its spectrum filter removed.  Consumer cameras has a special filter on the camera chip that passes the different wavelengths of visible light (the colors) at different amounts in a way that matches how the human eye responds to color.  This way, images come out looking mostly like how you saw them in real life.  However, the human eye is not particularly sensitive to red, which unfortunately is what a lot of the pretty stuff in the universe emits, especially nebulae.  With the spectrum filter removed, far more red can make it to the camera chip, which increases your signal-to-noise ratio at those wavelengths by quite a bit.  I've seen some amazing images from astro-modified DSLRs.  I've thought about doing it myself, but I think I'll save the money and get a color astro camera instead (such as the ZWO ASI1600MC, the color version of my ASI1600MM Pro) so that I can also have the cooling system.

We had a few issues at the start getting it rolling though.  It had one of those spare battery and memory card compartments attached to it, and for some reason it wasn't liking some of the batteries.  So we finally put just one battery in instead of two, and it seemed happier.  Then, when I was scrolling through the menu options (after having Alain help me change it from French to English), it kept seeming to push buttons on its own!  Finally I called Alain over to take a look, and he just gave me another astro-modified Sony a7s to use instead.  That one seemed to work.  

The Sony a7s is a mirrorless camera, meaning that much like point-and-shoot cameras and video cameras, the viewfinder is electronic.  In order to actually see anything, the image gets stretched quite a bit, so it was far easier to get the camera pointed at what I want, since I could see it on the screen so easily!  It also went up to stupidly high ISO values, like 64,000 (not 6400, 64,000!).  

Now, the Sky-Watcher Star Adventurer actually has two camera-connection screws: one on top of the declination adjustment plate, and one further down on the dovetail.  So what did I do?  Yes that's right.  I put both DSLRs on it - the Sony a7s, and my own Nikon D5300!  Actually, having the D5300 in the lower camera spot, which is toward the middle of the camera-counterweight balance point, helped balance it quite a bit, which was perfect.  The only issue I ran into was that I had to point the cameras carefully, since they would run into each other.  It meant I couldn't quite point both where I wanted to, but I got close enough.  I wound up swapping out the 300mm lens for the 35mm to avoid problems.

Simply glorious -- allllll the imaging!

It was a challenge to focus the Rokinon lens since the focus point was very tight!  But I finally got close, and then pointed the Sony toward Eta Carinae and the Running Chicken Nebula area.  I had to rotate it sideways to avoid seeing a refractor at the front of the shed.  I set the exposure time to 30s because at ISO-1600, one minute was overexposing the image!  The images looked very red due to the lack of spectrum filter, but that will all come out in processing.    Then I pointed the D5300 up to the Rho Ophiuchi region, which took a while to finesse into place so that I could get the most of the dust clouds, but not also get super-bright Jupiter in the scene.

Once that was all set and rolling, I wandered back over to the scopes to see what John and Beth were up to.  John had the 28-inch looking up at Jupiter, which was incredible in the eyepiece!  So bright, and so much detail.  It's so much higher down there than it is up in the US, plus the skies were very clear and steady.  It was breezy out, which made it feel much colder, and the moon was still up and brightening the sky, so we went inside to warm up and wait for it to set.  In the meantime, we worked through some wine we had bought and needed to finish before we left on Thursday.

I went back to the shed later to swap batteries and re-position cameras, including on my Nikon D3100, which I had set up on my mini-tripod to do star trails/timelapse facing south over the robotic scope domes.  

Then it was back to more visual observing -- M25 open cluster, Sculptor/Silver Dollar Galaxy again, NGC 1365, Stephan's Quintet, more Tarantula Nebula, and more 47 Tucanae.  NGC 1365 is a gorgeous barred spiral galaxy in the constellation Fornax, and I could see its shape!  Very very cool.  It's about 60 million lightyears away.  I also tried to find the Bug Nebula, but was unsuccessful.  At some point, I went back over to the shed and changed the Sony to imaging the Large Magellanic Cloud, and the D5300 over to both clouds with its 35mm lens.

Large Magellanic Cloud single frame at f/2, ISO-1600, 30s
Don't worry, the red will process out...

Single frame at f/2.2, ISO-1600, 60s
Caught a meteor in one of the frames!

After over an hour of imaging at those spots, I discovered that I had accidentally left the D5300 set on 10s instead of Bulb from when I was centering the Magellanic Clouds!  It had been imaging for quite a while at that point, but I switched it back to Bulb anyway for the 60s images I had set on the intervalometer.  At 5 AM, I was tired and ready for bed, but since it was still dark until about 6 AM, I left the cameras running this time.  I had started the Sky-Watcher far enough east that I was pretty sure it wouldn't hit the mount before I woke up to shut off the power, and the shed would close at sunrise to protect from the sun (I was pointing south anyway, away from the sun).  Plus, the batteries would die at some point.  So I left it running and went to bed.  

Another fabulous night (and day)!


[ Update July 27, 2019 ] 

Large Magellanic Cloud

Still plowing through datasets...so many left to go!  But each one is a joy!

Here's the Large Magellanic Cloud, from the astro-modified Sony a7s with the Rokinon 135mm f/2 lens, both borrowed from the Atacama Lodge owner, Alain Maury.

Date: 9 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Large Magellanic Cloud
Attempt: 1
Camera: Sony a7s (Alain Maury's)
Telescope: Rokinon 135mm f/2 lens at f/2
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 259x30s (2h9m30s)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 0
Flats: 0
Temperature: 30-32F

😁😁😁😁😁😁😁😁😁😁😁😁
Wowee!  So much detail!  So cool!!
The Large Magellanic Cloud is a dwarf galaxy that is very close to our own -- only 160,000 lightyears away.  It was previously thought to be orbiting the Milky Way galaxy, but we now know from velocity measurements that it's actually just passing through, although it's expected to collide with us in about 2.4 billion years.  It's a disrupted barred spiral galaxy, with the disruption being due to the gravitational interaction between the LMC and the Milky Way.  It's easily visible naked-eye from relatively dark places, and from the darkness of the Atacama Lodge, I could make out structure, especially with averted vision.  It's home to the massive and incredible Tarantula Nebula as well.

Using an astro-modified Sony a7s was fun!  The images were very low-noise -- I didn't have to do any denoising at all while processing these, and I don't even have dark or bias frames for calibration!  The stars were also nice and small, and the detail was just awesome, largely due to the lack of noise I think.  When can I get one of these??

My PixInsight process was as follows:
- Since no darks/biases, started with SubframeSelector
- Scale: 12.82 arcsec/px
- Gain: 0.316 e/ADU (est.)
- Highest-score frame: DSC00136 (86.020)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear Fit
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Color correction with PhotometricColorCalibration
- Applied deconvolution with Deconvolution, with a PSF generated from the image with DynamicPSF, 30 iterations, range_mask - star_mask masking
-  Adjusted curves with CurvesTransformation and ColorSaturation
- Enhanced contrast with HDRMultiscaleTransform

Large and Small Magellanic Clouds together

This one was with my own Nikon D5300!  Like I mentioned, I accidentally took a ton of 10s photos before I realized it and switch to 60s, but together I got about an hour and 45 minutes out of it.  And it came out quite well!

Date: 9 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Magellanic Clouds
Attempt: 2
Camera: Nikon D5300
Telescope: Nikon 35mm f/1.8G @ f/2.2
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 48x60s
   355x10s
   Total: 1h47m10s
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 72 (30F)
Biases: 20 (28F)
Flats: 0
Temperature: 29-30F

Not much is visible of the Tarantula here, but the globular cluster 47 Tucanae shines bright just beside the SMC.  The stars in my 35mm lens often come out with a pink-magenta-ish tinge, so I had to use a star mask that I enlarged a bit in order to reduce the pink-purple saturation just for the stars.

My PixInsight process:
- Generated master bias & superbias
- Calibrated darks with superbias, integrated with ImageIntegration
- Showed a weird pattern down at the bottom of the frame - calibrated with master bias instead and stacked, looked much better
- Calibrated 10s frames with master bias, and 60s frames with master bias and master dark
- SubframeSelector:
- Scale: 23.07 arcsec/px
- Gain: 0.115 e/ADU
- Highest-scoring 60s frame: DSC_0735 (89.446)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Linear Fit clipping
- Combination: Average
- Normalization: Additive
- Cropped with DynamicCrop
- DynamicBackgroundExtraction
- Denoise with MultiscaleLinearTransform, with lum mask
- Color corrected with PhotometricColorCalibration
- Tried Deconvolution with generated PSF and range_mask-star_mask, but wasn't doing much
- Stretched with HistogramTransformation
- Reduced pink tinge in stars with ColorSaturation and star mask
- Applied HDRMultiscaleTransform, 9 iterations
- Dilated star mask, tried reducing magenta star tone with ColorSaturation again
- Cropped again to cut out telescope shadow and some coma
- Applied ACDNR for some additional noise reduction in brighter areas

Eta Carinae & Friends

This was one of the first datasets I processed after I got home because I was so excited about capturing hydrogen regions with the Sony a7s.  And I was not disappointed!!

Date: 9 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Eta Carinae Nebula and Running Chicken Nebula
Attempt: 3
Camera: Sony A7s (borrowed)
Telescope: Rokinon 135mm f/2 (borrowed)
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 43x30s
Gain/ISO: ISO-800
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 0
Flats: 0
Temperature: mid-40s

Just look at all of those stars!!  And they look nice and tight, with tons of detail on the nebulae!  And loads of dark nebula streaks.  I am super excited about this one.

Here's my PixInsight process:
- No darks or biases, so went straight to SubframeSelection:
- Scale: 12.82 arcsec/px
- Gain: 0.158 e/ADU (est.)
- Highest-scoring frame: DSC09400 (94.882)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Norm: Average
- Pixel rejection: Linear fit clipping
- Applied DynamicBackgroundExtraction
- Literal tears in my eyes!
- Denoised with MultiscaleLinearTransform
- Didn't necessarily need it, but softened the image a bit in a good way
- Color correction with PhotometricColorCalibration
- Deconvolution with generated PSF from DynamicPSF, range_mask-star_mask, 30 iterations
- Stretched with HistogramTransformation
- Fine-tuned with CurvesTransformation
- Ran DarkStructureEnhance script

Yes, when I ran the DynamicBackgroundExtraction process after carefully adjusting every sample point so as not to be over a star or nebulosity, by jaw hit the floor.  It was so beautiful!


DynamicBackgroundExtraction forever!!

I will write a blog post on my new workflow and provide a step-by-step.  I haven't had time -- it takes a ton of time to do that!  But I will, I promise!

[ Update August 17, 2019 ] 

Still working through my Chile data...very excited about this image of the Milky Way with the Sony a7s and Rokinon 135mm lens!  Got some nice detail in the twisting dust clouds, and some nice color.

Date: 9 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Milky Way (Sagittarius)
Attempt: 10
Camera: Sony a7s (ILCE-7S) (astro-modified)
Telescope: Rokinon 135mm f/2 @ f/2
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 236x30s  (1h58m)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 0
Flats: 0
Temperature: 40-45F ish

Here, we are looking at several nebulae, star clusters, and a ton of dark molecular dust in the core of the Milky Way. The big pinkish nebula right of center is M8, the Lagoon Nebula, with M20, the Trifid Nebula, lying just below and to the right. Just to the right of M20 is open cluster M21. The large open cluster in the lower right of the image is M23, which contains about 150 stars in an area 20 lightyears wide. Close inspection of the image reveals a lot of intricate detail in the twisting dust clouds above and below the main dark band of the galactic center.

PixInsight process:
- No darks/biases, so started with SubframeSelector:
- Scale: 12.82 arcsec/px
- Gain: 0.316 e/ADU (est.)
- Highest-scoring frame: DSC09658 (85.816)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear Fit clipping
- Tried denoising with MultiscaleLinearTransform, but didn't really need it, and killed the 
dimmer stars
- Color corrected with PhotometricColorCalibration
- Same as 1, but I did Deconvolution with range-star mask, PSF from DynamicPSF, 15 iterations
- Stretched with MaskedStretch
- Adjusted with CurvesTransformation
- Cropped to center portion that I liked more
- More CurvesTransformation
- DarkStructureEnhance

So much fun :D

[ Update August 31, 2019 ] 

Almost through all of my Chile data!  Tons of great widefield Milky Way shots.  Here's another one!

Date: 9 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Milky Way
Attempt: 11
Camera: Nikon D5300
Telescope: Nikon 35mm f/1.8G @ f/1.8
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 171x60s (2h51m)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 46F: 56
   40F: 40
   34F: 20
Biases: 46F: 20
40F: 20 (actually 42F)
34F: 0
Flats: 0
Temperature: 35-47F

I learned something interesting in processing this dataset.  The first half of the night had a pretty bright moon (hence the large temperature difference through the dataset), so I stacked the image twice: once with all of the images (that made it through quality check), and once with just the ones without moonlight.  There was actually not much difference at the end of the day between the two datasets!  I had to do some extra gradient removal on the moonlit one, but it wasn't too hard, and I actually liked the result better.  Here's the one without any moonlit frames (which amounted to be 70x60s):



The blue gradient is still there (I didn't try to remove it in this one), and I prefer the look of the first image.  (The main reason the two look different is just slightly different processing -- I didn't save out every process to exactly repeat all of the steps).  So that is a really interesting result -- I can do just about as well with moonlight as without!  For bright objects like the Milky Way, at least.  Processing can do a lot for you if done well.





Friday, July 26, 2019

#196 - Monday, July 8, 2019 - High-Tech Star Hopping

After hitting the sack at 5:45 AM, I managed to sleep until 12:45 PM, thanks to my sleeping mask!  It was so bright though that I could see light through it still :/  My travel companions John & Beth saved the shower for me this time, so I had some hot water and water pressure, which made for a much more enjoyable experience than the day before!

We just hung around the lodge again all afternoon, and I worked on organizing data.  We then decided to drive over to this beautiful lookout spot that overlooked a jagged, rocky miniature canyon only a few miles from us, where people gathered every night to watch the sun set over the rocks and the Andes mountains in the background.


I took a bunch of images to make a timelapse, which I haven't made yet, but I'll add it here once I do!  It was beautiful to watch; the shadow of the mountains on the other side slowly creeped across the landscape, the sky above the Andes was orange, and the mountains themselves a peach-pink.  A dark band appeared above the mountains later on, and then the sky faded to dark blue.  

After sunset, we drove back to the lodge, made hamburgers on the stove for dinner, and then around 7:45 PM, I went to set up my Nikon D5300 on my Sky-Watcher Star Adventurer mount with my 70-300mm lens.  Since Alain, the Atacama Lodge owner, had helped me polar align it the night before, and I had weighted down the tripod with some heavy stuff I found on the floor of the roll-off shed (a counterweight and a few other random items), it should track pretty well even at 300mm!  I pointed it at the Eta Carinae Nebula and took some test shots, which showed that I could go as long as 90s without streaking.  Not bad for 300mm unguided!  My next project for the Star Adventurer is to get a guidescope attached to it.  I have some CCTV lenses and a C-mount to T-thread converter; now I just need to figure out a way to attach it to the mount.  Anyway, I got a good amount of detail to show up at 90s -- can't wait to stack it!

Eta Carinae Nebula, single 90s frame, Nikon D5300, 300mm, f/5.6, ISO-1600

It was nice and warm out that evening -- my digital thermometer in the roll-off shed said 46F, which is downright balmy after the 32F the previous two nights!  So I went over to the 20-inch-ish Dob near our lodge and looked for a bunch of stuff with John and Beth.  The large French were having some big fancy dinner in one of the other lodges, so we had it to ourselves.

First, we viewed the Eta Carinae Nebula with the OIII filter, which Beth had been absorbing all evening.  There is so much to see!  It is seriously impressive at the eyepiece.  As was massive globular cluster Omega Centauri of course, sporting hundreds if not thousands of resolvable stars under the dark, steady skies.  It's thought to contain as many as 10 million stars, making it the king of globular clusters in the Milky Way galaxy.  Many of its stars are 12 billion years old!  These millions of stars are packed into an area only 150 lightyears across, which from Earth appears nearly as large as the full Moon on the sky.  It's estimated that the average distance between stars is only one-tenth of a lightyear!  Now imagine living on a planet with that many bright stars in the sky.

I wanted to see Centaurus A next.  It's a big enough Dob that I couldn't quite figure out how to star-hop, especially since many of the stars were unfamiliar, and I couldn't tell which was which between my phone app map and the eyepiece.  So instead, I brought a little technology to the task!  I looked up Centaurus A's current altitude and azimuth in my SkySafari app (there's a free version known as SkyPortal, FYI).  I then used my phone's compass to point the scope in the right direction, and a level indicator in an app I use all the time called GPS Status to get the elevation set close.  Then I fished around for a bit, looking for star patterns that matched up with SkySafari, and boom, there it was!  It wasn't terribly bright, but you could definitely make out the hamburger shape.  It's quite large on the sky, so it's rather diffuse in the eyepiece.  I found an object in a Dob all by myself, woo hoo!

We swung by the nearby Southern Pleiades, a gorgeous open cluster that you basically trip over anytime you're looking from something around Eta Carinae, and then hopped over to Saturn.  It was incredibly sharp in the high-altitude, steady desert air, making the Cassini division very easy to see, in addition to several cloud bands.  And it was so dark that I saw more moons than I had ever seen before!  I checked their positions in SkySafari.  Previously, I'd only seen Titan and I think Tethys once or twice, but clear as day, there were Rhea, Dione, Enceladus, and Tethys!  Titan was pretty far outside the view in the eyepiece.  So cool!

We checked out the open cluster in the Coalsack Nebula, and then I went hunting for the Running Chicken Nebula, but could only see the open cluster Lambda Centauri and no nebulsoity.  Darn!

Photo by John - light is from the moon

Throughout the night, I ran around taking pictures of stuff with the sky in the background using my 35mm lens on my other DSLR, my Nikon D3100.


After a snack back in the lodge, I went back over to my Star Adventurer to change my D5300 over to somewhere in the vicinity of M8 & M20, the Lagoon and Trifid Nebulae.  They were up at zenith, which would make for some very clear shots!  It also made it hard to aim the camera.  While I was adjusting my headlamp out of the way, it snapped off, and the pieces went flying.  So I fumbled around for a few minutes until I found all the batteries and plastic, snapped it back together, and went back to finding M8 & M20.  I finally found it, but then I worked on getting it centered, which took another several minutes!  Finally got it where I wanted it.  Mostly.  Or I just gave up.  I really wanted to get the cloud below M8, which I have tried to capture before but haven't succeeded.  I can just barely see it in the subframes, so here's hoping it comes out in stacking!  It probably will, stacking is magic.

M8 & M20, Single raw 90s frame, Nikon D5300, 300mm, f/5.6, ISO-1600

After another snack around 11:30 PM (staying up all night is a lot of work!), I went over to the big telescopes, since the tour groups had cleared out.  I tried my hand again at finding stuff, and found quite a few things in the 28-inch and 24-inch Dobs!  A few from the French group were there, and they pulled up the Lagoon Nebula through the 24-inch, and helped me find the Dumbbell Nebula (way harder than it should have been!).  Then I spent quite a bit of time hunting down the Veil Nebula up in Cygnus, and I did finally find the Western Veil.  The OIII filter had disappeared somewhere, so I didn't get to see it with that (which would have been awesome), but it was really cool to see this giant, gray whispy thing there in the eyepiece!  I went looking for the nearby Eastern Veil as well, but didn't quite find it.  I did see some other nebulosity though, potentially some of the Pickering region.  I got to see that through a 16-inch Dob at the Green Bank Star Quest in 2017 when it was way up at zenith, which was quite amazing to see, especially with an OIII filter.  

One really cool object that I am super proud that I found (with my high-tech technique!) is the Skull Nebula, NGC 246.  It's a planetary nebula in Cetus, and lies about 1600 lightyears away.  It's about twice the size of the Ring Nebula on the sky, making it somewhat diffuse and difficult to spot at higher magnifications.  It really popped out against the dark sky though as a fuzzy gray circle.  With an OIII filter, it really changed character -- I could see structure in it!  Like it had large lumps.  It doesn't climb very high in the northern sky, unfortunately.  It was super cool to see!  And I found it by myself!

While I was doing that, some of the French folks found a cluster of galaxies that I didn't quite catch the name of.  It was a really pretty grouping.  One thing that was interesting is that under the murky skies at home, adding more magnification to something usually fuzzes it out.  But the seeing was so good here that adding more magnification actually made it sharper!  My brain was too fuzzed out to remember what constellation we were looking in though, so darn.

Finally, the Large Magellanic Cloud was up high enough to image at about 3:30 AM, so I moved my D5300 over to that.  But I must have moved the tripod or mount or something a little because I was getting streaky stars!  So I gave up on that and went back to the telescopes.  Since the LMC was up, that meant it was Tarantula Time!  We got the 28-inch Dob pointed at it, and gasped in amazement.  It was beyond belief!  So much detail and blue-green color.  Truly breathtaking!  We kept taking turns looking at it.

Beth looking at the Tarantula Nebula in the 28-inch.

Since the Milky Way was now much lower in the sky, it was a great opportunity to take some epic-level images with scopes and stuff in the foreground.
Proooooobably the most epic selfie I've ever taken.  Just sayin'.
Nikon D3100, 35mm, f/1.8, 10s, ISO-3200

3-panel mosaic of the 28-inch Dob
Nikon D3100, 35mm, f/1.8, 10s, ISO-3200

I took one last look at the Tarantula Nebula, and then shut everything down and went to bed at about 5:30 AM.  Another truly, truly excellent night!

[ Update July 29, 2019 ] 

Processing the Eta Carinae Nebula

So 90 seconds proved to be a little too long at 300mm, unfortunately.  Either that, or the polar alignment got knocked out earlier than I thought.  In either case, I had to dump a lot of frames, and the frames I kept were barely marginal in the star shape.  But I processed it anyway, and it's not too bad of a result.  Dark skies buy you a lot.

Date: 8 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Eta Carinae
Attempt: 2
Camera: Nikon D5300
Telescope: Nikon 70-300mm f/4-5.6 G at 300mm, f/5.6
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 48x90s (1h12m)
Gain/ISO: ISO-1600
Acquisition program: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 20
Flats: 0
Temperature: 38-41F

This one wound up with an unusually green background somehow (airglow?) even after I ran the color correction, so I just tweaked the histogram at the end of stretching to kill the green background a bit more.  It worked nicely, and I was able to adjust the red and the blue as well so that the colors looked more natural.  I wound up with some blue halos from this lens, which I was able to reduce using Noel Carboni's Astronomy Tools for Photoshop when de-saturating blue with a star mask in PixInsight didn't really do anything.  Of course, the algorithm also killed the blue in the nebula a bit, which I had to add back using the Curves tool in Photoshop, which added back some of the blue halos.  Oh well!

Here's the PixInsight process:
- Created master bias with ImageIntegration
- Generated superbias from master bias
- Calibrated lights with superbias
- SubframeSelector:
- Scale: 2.69 arcsec/px
- Gain: 0.115 e/ADU
- Highest-scoring frame: DSC_0010 (90.716)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear Fit Clipping
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Denoised with MultiscaleLinearTransform
- Corrected color with PhotometricColorCalibration
- Tried Deconvolution, but didn't work very well
- Stretched with HistogramTransformation
- Eroded stars with MorphologicalTransformation
- Morphological Selection, 0.30
- Undid the erosion; caused some weirdness
- Adjusted with CurvesTransformation
- Reduced blue halos in Photoshop

It's a gorgeous nebula nonetheless!  Still have several more datasets to process.  Should I be packing for my upcoming move?  Yes...Am I? No...processing astrophotography is more fun than organizing my office!

[ Update August 30, 2019 ] 

I actually processed this one a month ago, but forgot to write it up in here!  Despite the subframes not being terribly exciting, this one came our rather nice.

Date: 8 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: M8 Lagoon Nebula & M20 Trifid Nebula
Attempt: 3
Camera: Nikon D5300
Telescope: Nikon 70-300mm f/4-5.6G @ 300mm, f/5.6
Accessories: N/A
Mount: Sky-Watcvher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 9x90s (13m30s)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 20 (28F)
Flats: 0
Temperature: 29-36F

That 70-300mm lens does have a bit of chromatic aberration, which causes the blue halos around the stars.  I have a Photoshop tool from the Noel Carboni Astronomy Tools for Photoshop kit that is great at removing those, but when they're in the middle of a big bright nebula (as is the case with M8), then holes are left where the halos once were, and the effect is worse.  I also tried to kill them in PixInsight using a star mask and desaturating blue, but it didn't help much, unfortunately.

Here's the whole process:
- Calibrated lights with previously-made superbias
- SubframeSelector
- Scale: 2.69 arcsec/px
- Gain: 0.115 e/ADU
- Highest-scoring frame: DSC_0225 (95.216)
- Debayered
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Winsorized Sigma Clipping
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Denoised with MultiscaleLinearTransform
- Color corrected with PhotometricColorCalibration
- Tried Deconvolution with DynamicPSF and range_mask-star_mask, but at a number of iterations low enough to not cause weirdness, effect is negligible
- Applied MaskedStretch, but stars got super blue; undid
- Stretched with HistogramTransformation instead
- Applied CurvesTransformation
- Tried to kill halos in PixInsight and Photoshop, but didn't help or caused problems
- Applied HDRMultiscaleTransform
- Tweaked with CurvesTransformation
- Denoised with ACDNR
- Sharpened with MultiscaleLinearTransform
- Applied DarkStructureEnhance
- Increased saturation of nebulae using range_mask and Saturation in CurvesTransformation


M8, the Lagoon Nebula, is the one at the center, and M20, the Trifid Nebula, is toward the upper left.  Also making an appearance is open cluster M21, beside M20.  There's a sort of bumpy nebula below M8 that I have tried to capture with M8 before unsuccessfully that I finally got some of this time!  M8 & M20 are near the heart of the Milky Way, so there's a lot of glowing stars and gas, along with dark dust, sharing the field as well. I had to ditch most of the images in this dataset because of polar alignment issues, but the nine I got to keep made a decent image despite that (thank you dark skies!)

The Lagoon Nebula is a large star-forming region somewhere between 4000-6000 lightyears from Earth. It's enormous, spanning 110 lighyears on the long axis. It also contains a number of Bok globules, which are dense clouds of dust that are in the process of collapsing into a star.

The Trifid Nebula contains three types of nebulae in one: emission, reflection, and dark. Emission nebulae are clouds of gas that are energized by a star and re-emit light, usually a red hydrogen glow. Reflection nebulae are clouds of gas that reflect starlight. Dark nebulae are clouds of molecular dust that absorb starlight. I got to see both of these in big telescopes at the Atacama Lodge as well, and they were awesome! No red color (our night vision has poor color), but some blue and the dark nebulae too.




Thursday, July 25, 2019

#195 - Sunday, July 7, 2019 - With My Own Eyes

After a late-ish first night of imaging under the dark Atacama Desert sky, I managed to sleep in until about 10:45 AM, but woke up with a raging headache.  Likely a combination of altitude, mild dehydration, and a late night.  Luckily we were well-stocked in the drug department, so I took some altitude sickness medicine and some ibuprofen.  And coffee.  The cure-all!


One of my two travel companions, John, cooked us a yummy breakfast of breakfast burritos.  We couldn't find any sour cream at the grocery store, or cheddar cheese, so we had the Chilean favorite gouda and some salsa we did manage to find.  He also did the dishes.  We told him he'd be allowed to sleep inside, with a blanket, and if he served us alcohol later in the day, maybe he could have a pillow too ;D


The water pressure had dropped during breakfast, so I waited to take a shower.  Finally in the early afternoon, it seemed to have gone back up, at least partially.  It took several minutes to warm up, but that was fine.  But then, halfway through my shower, the pressure dipped again, and it got cold!  So I wrapped up fast and hopped out.  Boo!

We decided not to go anywhere that day -- we were tired, particularly from the altitude, and after all of the adventures we'd had so far, a break was much needed.  So I worked on backing up photos and getting things organized.

At sunset, I went and found the Atacama Lodge owner Alain, who had dug up another counterweight for me, flipped the telescope around on its dovetail so that I'd have more room to push it forward for balance, and installed a Pegasus electronic focuser.  That one was a surprise, so I quickly got the driver installed for it.  Ultimately, however, I wasn't able to get my computer to talk to it, so I had Alain come back and disengage it so I could focus the ol'-fashioned way.  He told me to just use FWHM instead of a Bahtinov mask since it led me astray the night before.

I got it focused and went to align the mount, but then the power cable fell out.  Alain had split the cable coming out of the power supply to share with the focuser, and I think the plug he had on it was a little loose.  I tried the one on my ZWO camera to see if it was just the power supply or something else, but although the hand controller turned on, the mount itself didn't, and the hand controller said it didn't have any communication with the motors.  After being unsuccessful at finding another cable, and with Alain busy with tour groups, I gave up on the mount and turned my attention to my own Sky-Watcher Star Adventurer with my DSLR.

I put my 35mm f/1.8 lens onto my Nikon D5300 and pointed it toward the southern Milky Way, centering it on the Coal Sack Nebula.  It also captured Alpha Centauri, Beta Centauri, and the Southern Cross.

Coal Sack Nebula, with my Nikon D5300, 35mm lens @ f/1.8, ISO-1600, 60s

With the DSLR off and running, I went back inside to process my solar eclipse images until the scopes freed up after the tour groups left.  I wanted to make my composite corona image and get it out there before too much time elapsed after the eclipse!  The processing went really well, and you can see the result here on AstroBin.  I wrote in my eclipse day blog post about capturing the image, and then after the 2017 solar eclipse in the US, I wrote up a post about how I created the composite for that eclipse, and I used the same method for this one.

One of the tour groups

Later on, Alain took a look at the powerless mount, but couldn't immediately figure out what was wrong.  He helped re-polar-align my Star Adventurer, which went on to provide great images the rest of the night.  I pointed the camera up high in a gorgeous part of the Milky Way and let that run.

*drools*

Back in the lodge, John melted some of the chocolate over warmed crossaints, which made for a delicious and warm midnight snack on a chilly night.

We wandered up to the scope field after that, since all of the tour groups were gone, and split some time on the scopes with parts of the French group.  Now, I sometimes pepper in visual observations in between fussing over my cameras, mounts, and computers when I'm at the club's observatory or at a star party, but since the mount wasn't running and the 35mm lens on the Star Adventurer hooked up to AC power required little attention, I spent most of the rest of the night witnessing the wonders of the southern sky with my own eyes.  I love astrophotography -- pulling signal out of the noise, getting this incredible image of an amazing object that is hard to believe really exists -- but there is a special kind of wonder with visual observing.  There's the challenge of finding the object, then observing deeper into it to see what can be seen, and on top of that, there's the knowledge that some photons that were emitted thousands or millions or lightyears away are finally coming to a rest in your eyes.

First, the French had the the Tarantula Nebula up in the 28-inch Dob, an enormous nebula in the Large Magellanic Cloud (like actually in it, meaning that it's something like 1000 lightyears across!), which under low power looked "dim and chunky, with three chunks" according to my hastily-typed notes.

At our request, we looked at the massive globular cluster 47 Tucanae, which is just off the edge of the Small Magellanic Cloud (but belongs to our galaxy).  It has something like ten thousand stars packed into 120 lightyears, and is second only to Omega Centauri in brilliance.  It was dazzling in the 28-inch Dob under dark, steady skies!  It seemed to spiral around in my eye.

Next,we looked at NGC 253, the Silver Dollar or Sculptor Galaxy.  It's nearly edge-on to us, but not quite.  It looked positively 3D in the telescope!  Very cool effect standing out against the background darkness.

Over in the nearby 24-inch Dob, another one of the French group had pulled up the Helix Nebula.  The other nebula filter was off somewhere, so it just looked like a formless smudge, unfortunately.

Back over on the 28-inch, a higher-power eyepiece had been inserted, and the Tarantula Nebula re-acquired.  I took a look, and HOLY COW it was incredible!  It had so much structure in light!  And it was in another galaxy!!  It showed a green-blue color, forked with dark nebula clouds spreading out from the middle.  There was so much detail to take in, you could just stare at it forever.  What an incredible thing to see!

By this time, it was about 4 AM, and I looked east, hoping to spot the zodiacal light.  And there it was!  A dim, but definitely noticeable, column of light that extended at least up to zenith.  Alain showed us the latest image pulled down from his all-sky camera, which is extremely sensitive, and it showed the arc going all the way across the sky, from horizon to horizon!  It was really cool.  Zodiacal light is caused by sunlight that is scattered by interplanetary dust in the plane of the solar system (aka, the plane of the ecliptic).  It's called zodiacal light because the the band it lights follows the Zodiac signs, since these are constellations that are along the plane of the ecliptic.  The small particles of dust range in size from 10-300 microns (ten-thousandths of an inch)!  It is best observed in the western sky in spring after twilight, or the eastern sky in the fall before sunrise, when the ecliptic is highest.  In northern Chile, being in the southern hemisphere, the ecliptic was almost directly overhead, so it made for excellent conditions.

  Not the best photo of it, since I didn't have a fast-enough, wide-enough lens to do it justice, but you can kind of see the zodiacal light right behind the Pleiades!  Taken at 4:32 AM.

The French located a galaxy cluster in Fornax that I didn't quite understand what they were saying the name was, but it was a gorgeous, tight grouping of 5 galaxies I think, of which I spotted 4.  I also enjoyed some binocular views of the Pleiades, the Lagoon Nebula (M8), and the Andromeda Galaxy with my 10x42 Meade sport binos.  I could see Andromeda naked eye as well as a dim smudge, low on the horizon.  

Back at the scopes, we looked at M17, the Swan Nebula, which was absolutely gorgeous.  I always think it looks like a fountain spring.  It showed lots of structure and detail, especially with the OIII filter.  I suggested we also look at M20, the Trifid Nebula, with the 24-inch while I was over there.  I could see the emission part of the nebula (which is red in pictures, but I just saw the blue-green component), and the dark nebula that criss-crosses it, but I couldn't quite eke out the reflection nebula portion.  Maybe if I'd spent more time with it.  It was also getting lower in the sky by this time of the morning.


After shutting down my gear, I finally crawled into bed at 5:45 AM.  What a night!

[ Update July 25, 2019 ] 

Now that I'm finally writing this post, I'll include a blurb on the Coalsack Nebula image that I mentioned above, only now it's processed!  I knocked that one out last Wednesday after work.

Date: 7 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Coalsack Nebula
Attempt: 1
Camera: Nikon D5300
Telescope: Nikon 35mm f/1.8G at f/1.8
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 33x60s (33m)
Gain/ISO: ISO-1600
Acquisition program: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 56 (46F)
Biases: 20 (46F)
Flats: 0
Temperature: mid-40s

The Coalsack Nebula is a massive dark nebula just above the Southern Cross constellation.  It's relatively nearby, only 600 lightyears away, and spans about 70 lightyears.  Dark nebulae are clouds of molecular dust that absorb light, and the Coalsack appears as a "hole" in the Milky Way (although really is stands between us and the galaxy's core).  In some Australian Aboriginal cultures, the Coalsack was the head of a massive emu in the sky.  In others, it's the head and shoulders of the "law-man," watching the people to keep the traditional laws.  In Inca astronomy in South America, it was known as Yutu, which is a partridge-like southern bird, also known as a tinamou.  It's also featured in several sci-fi references, including the original Star Trek series, 2001: A Space Odyssey, and many more.

In PixInsight, I did:
- Created master bias with ImageIntegration
- Generated superbias from master bias
- Calibrated dark frames with superbias (Linear Fit clipping)
- Calibrated lights with darks and superbias
- SubframeSelector
- 23.07 arcsec/px
- 0.115 e/ADU
- Best frame: DSC_0234 (85.502)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Linear Fit clipping
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Denoised with MultiscaleLinearTransform
- Color corrected with PhotometricColorCalibration
- Stretched with HistogramTransformation
- Tweaked with CurvesTransformation
- Used star mask and ColorSaturation to reduce pink color of stars
- Tweaked again with CurvesTransformation

This one had some purple-y stars that were difficult to reduce, but I was able to correct them somewhat.  It's an artifact of the lens.  

[ Update August 18, 2019 ] 

Getting closer to the bottom of the data pile!  I need to start working on making videos out of my timelapse data too...

Anyway, here are the Magellanic Clouds!

Date: 7 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Magellanic Clouds
Attempt: 1
Camera: Nikon D5300
Telescope: Nikon 35mm f/1.8G
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 44x30s (22m)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 30
Biases: 0
Flats: 0
Temperature: 31-36F (mostly 33)

For this dataset, I had accidentally left the camera set to 30s, but it worked out all right anyway, since the shorter exposure time that less periodic error could creep in, which gave me a crisper image.  The red glow on the right side is from being low on the horizon (I rotated the camera to squeeze them both in).  

As I was starting to process this one, it struck me that I have imagery of the Magellanic Clouds!  I'm so happy that I got to go image in the Southern hemisphere.  I knew I wanted to do it at some point, but I didn't think I'd get to do it this soon!  Super super thankful.  

Here's the PixInsight process:
- Integrated darks with ImageIntegration to make master dark
- Calibrated lights with master dark
- SubframeSelector:
- Scale: 23.07 arcsec/px
- Gain: 0.115 e/ADU
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear fit clipping
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Denoised with MultiscaleLinearTransform, with lum mask
- Color-corrected with PhotometricColorCalibration
- Applied Deconvolution, with range_mask-star_mask, DynamicPSF, 10 iterations
- Stretched with MaskedStretch
- masked_stretch_2: undid stretch, did another DBE but division to help with gradient, then
did MaskedStretch
- MaskedStretch pulled out some weird star gradients
- Undid MaskedStretch and stretched with HistogramTransformation instead
- Tweaked with CurvesTransformation
- Went back to un-stretched image, applied DBE again with more sample points in red area
of upper right hand corner to target the gradient
- Stretched with HistogramTransformation, adjusted with CurvesTransformation

There is usually some trial-and-error involved!

[ Update: October 13, 2019 ] 

I've gotten sidetracked on processing data from my backyard, and I forgot I had one more dataset from Chile: another Milky Way shot!  The one I showed the image of on my DSLR screen above.

I struggled with the pink-purple tone added to the stars from chromatic aberration of the lens, but got it down to acceptable levels I think.  Love the dusty detail here!

Date: 7 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Milky Way
Attempt: 10
Camera: Nikon D5300
Telescope: Nikon 35mm f/1.8G at f/2.2
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 38x120s (1h16m)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.7
Post-Processing program: PixInsight 1.8.7
Darks: 23 (38F)
Biases: 0
Flats: 0
Temperature: 34-39F

This view is through my 35mm f/1.8 lens, and peers deep into the southern part of the Milky Way, but still up high near the core. Just off the right edge is a part of the Milky Way familiar to northern observers -- a little bit of the Pipe Bowl Nebula, the Butterfly Cluster (M6), and Ptolemy's Cluster (M7) above. To the left of that area you can see some of the pink fuzziness of the Cat's Paw Nebula. Near the center lie the beautiful open clusters of Collinder 316, Trumpler 24, and NGC 6231, with open cluster NGC 6124 nestled in the dust clouds below. The left portion of the image is within the southerly constellation Norma. The bright dot in the far lower right corner is interloper Jupiter.  You can check out the labeled image in AstroBin.

Sometimes my wide-field Milky Way images can come out with over-dominant stars, but this one did okay.  I did reduce the stars a bit using this tutorial from Light Vortex Astronomy that works reasonably well most of the time.

Here's the whole process:
- Stacked darks with ImageIntegration
- Calibrated lights with master dark using ImageCalibration
- SubframeSelector:
- Scale: 23.07 arcsec/px
- Gain: 0.115 e/ADU
- Highest-scoring subframe: DSC_0265 (85.351)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear fit clipping
- Cropped with DynamicCrop
- Background removal with AutomaticBackgroundExtraction
- Denoised with MultiscaleLinearTransform, with luminance mask
- Corrected color with PhotometricColorCalibration
- Stretched with MaskedStretch
- Adjusted with CurvesTransformation
- Reduced pink tone in stars by making a star mask with StarMask, then desaturating with ColorSaturation
- Reduced star sizes use Light Vortex method
- Increased saturation with CurvesTransformation
- Used dilated star mask to reduce pink tone again, expanded ColorSaturation de-saturation into purple
- CurvesTranformation with the star mask helped some more
- Tweaked a bit more in Camera Raw in Photoshop

What a great trip!  I got so many amazing images!  Now to decorate my house with them.  😁  (You can too!)





Sunday, July 21, 2019

#194 - Saturday, July 6, 2019 - In the Atacama Desert

After a few more days in La Serena following the solar eclipse, we started a three-day road trip up the coast and then inland to Calama, and then on to San Pedro de Atacama.  We stayed overnight in ChaΓ±aral and Antofagasta on the way up.  The desert landscape was like from another world!  There were many places where there was absolutely nothing but rock and sand.  And the occasional guanaco.  We got out at a guanaco observing spot near the Paranal Observatory, and sure enough, we saw one!  And then it made a funny noise and ran off.  Besides the crunching of our feet on the gravel, it was absolutely, perfectly silent.  We couldn't even hear the wind in this little valley we were in.  I had never heard such wide-open silence before; it was totally eerie and incredible.  A Girl Scout badge I led with a middle school group when I was in college talked about different kinds of pollution, including sound pollution, and it talked about the quietest square inch of space on Earth.  When a car wasn't passing by, this had to be it!


We were basically on Mars.  But with more oxygen.

What made it especially crazy was the fact that we were not at all far from the ocean.  In some places, we could see barren desert one one side of the road and crashing waves on the other!

The highway we were on took us past the Paranal site of the European Southern Observatory, and while we hadn't been able to get a tour there when we tried, we hoped there might be a cancellation, and at least we could see them from a distance if not.  We were out of luck, but the gate guard let us use the restroom there and re-fill out waterbottles, which was very nice.  We took plenty of pictures from the parking lot.  Yay for my long lens!

Paranal Observatory, from a distance

Posing with the sign

The altitude at the parking lot was around 7800 feet!  

In Antofagasta, our hotel was right on the beach, so we enjoyed watching the waves ceaselessly roll in, ever-changing, but ever the same.  It was hypnotizing.  

The Pacific Ocean -- the color of the water was beautiful!

On the third day of the road trip, Thursday, we drove for three hours from the coast up to the 7400 feet of the town of Calama.  We stopped at a large grocery store there called Jumbo (like Chilean Walmart, but a little nicer), since it was easier to get supplies there than in San Pedro de Atacama.  However, due to the sudden change in altitude, we were all lethargic, sick, and crabby.  So we tried our best to hold ourselves together while we shopped quickly, and then drove the next hour to San Pedro de Atacama, and the Atacama Lodge.

The Atacama Lodge is an amateur astronomer's dream land, owned by French ex-pat Alain Maury, himself an astronomer who grew tired of the light pollution and the politics of France and sought better skies.  It grew to be part robotic scope operation, part astro-tourism, a few kilometers south of the touristy village of San Pedro de Atacama in northern Chile, lying in the shadow of the volcanic Andes Mountains.  He hand-built a sunflower field of telescopes, with which he hosts nightly tours in three languages to showcase the wonders of the Southern skies.  


Less of a hotel and more of a nice set of adobe cabins, the accommodations were charming and fun.


My room

John & Beth's room

Gorgeous mosaic tile in the bathroom

Kitchen & dining area, complete with cookware and dishes.  And, very importantly -- a coffee maker!

Actual thatch roof!

Bonus, it had a heater, which none of our previous hotels had, which was a godsend.  The forecast showed that it would dip into the 30s every night!

Once Alain himself finally returned from a grocery run to Calama, he quickly got me set up on the Sky-Watcher AZEQ6 with a Takahashi FSQ-85ED before he had to zip off for that night's astro-tours.  The mount was located in a giant motor-driven rolloff shed that contained several robotic scopes owned by people from around the world, including one owned by none other than Guylain Rochon, the man behind the BackyardNikon and BackyardEOS camera-control software that I use.  Since the shed automatically opened and closed at sundown and sunup, I'd be able to leave everything connected, and it would be kept safe from the heat and the dust during the day.


Alain ran back to his house and got the key for the little half-door, but couldn't get it to unlock.  After much effort, including attempting to remove the lock from the door (he just jumped over the half-wall to get to the inside), we finally just set up a chair on the inside and outside to use to help climb over the wall!  I got pretty good at it by the end of the night in the dark.

The Takahashi didn't have a guide scope attached, but Alain said it wouldn't need it, and I hoped he was right.  I had prepped the software on my computer for plugging the hand controller in via serial-to-USB cable and running it using the SynScan driver and app, but he didn't have that cable -- instead, the AZEQ6 had a direct USB cable, like the Celestron CGX-L mount, which I had no idea it had.  This required EQMOD to run.  Before it got properly dark, I went back to the wifi in the lodge to install EQMOD, but I couldn't get the driver to show up in ASCOM when I tried to connect to it in Cartes du Ciel.  So instead, since I wasn't guiding, I just used the hand controller and didn't bother with trying to control it from my computer.  I just hoped the gotos would be good enough to not need a finderscope, which it also didn't have.  I got my ZWO ASI1600MM Pro and Starlight Xpress 2-inch filter wheel attached without issue.  Alain had a Takahashi-to-T-thread adapter handy (although I had brought mine just in case). 

My ZWO ASI1600MM Pro camera and Starlight Xpress filter wheel attached to Alain Maury's Takahashi FSQ-85ED on a Sky-Watcher AZEQ6 mount.

Sunset was gorgeous, especially the way the Andes changed colors.  I have a timelapse video that I'll put together (eventually), which I'm really excited about.


Once it got darker, I needed to get the camera focused.  I had it slew to a bright star, but since I wasn't sure how well polar aligned it was at the moment, that star did not end up in the field of view of the camera.  I cranked up the screen stretch on the histogram in SharpCap, but still couldn't even see any giant blobs.  So instead, I slewed it myself over toward some patch of the Milky Way, where I knew there would be stars in the field no matter where I pointed.  After over-stretching the histogram, I saw some giant blobs, and was able to get the scope roughly focused for alignment.  I would like to take a moment to point out something amazing -- this is a one-second exposure.  There were so many stars!  It was so dark that many more stars than usual could stand out.


Wowee!!
Next, I ran the polar alignment process in SharpCap, which it was capable of doing in the southern hemisphere the same way it does in the northern -- by way of plate solving.  


It was during this process than I ran into my next stumbling block -- Alain had showed me where the RA and dec clutch knobs were, but I couldn't remember where the RA one was.  So I tried various things for about 15 minutes before I finally figured it out!  But I finally got the darn thing polar aligned.  I also balanced it before polar aligning, although I wasn't able to balance it in dec because I ran out of dovetail to move it any more forward to compensate for my camera gear on the back.

Next was alignment, which I did with the hand controller in a very similar process to Celestron.  The stars landed in the FOV for every star, which was very exciting and helpful.  Finally, after focusing on a bright star with the Bahtinov mask I'd brought with me, it was time to line up my first target.  I chose something easy -- compact and relatively bright -- for my first target: Centaurus A.  It's a large, oddly-shaped galaxy, somewhere between 10-16 million lightyears away, also sometimes called the Hamburger Galaxy. Viewing it visually makes that moniker choice obvious -- it was a bright upper and lower hemisphere, split by a thick dark band of dust, making it look very much like an enormous hamburger in the sky.  You can see it from the southern United States -- from the 29 degrees north latitude of the Texas Star Party, it crests at 12 degrees off the horizon or so, just high enough to let it peak for an hour or two above the hills.  But here at 22 degrees south, it was quite high in the sky, with much less atmosphere between me and it.  Thanks to the dark skies, it was very easy to see with 1-second exposures in SharpCap, so I centered it by hand, switched over to SequenceGenerator Pro, keyed up the sequence I wanted, and let it run.  The plan I had developed several months ago for which targets I was going to image when called for starting with RGB that night before changing targets for the second half of the night -- with RGB, I'd have a complete dataset, in case something broke later in the week and I didn't get to finish.  Having a luminance channel is great, but not required.  

I took a few test frames first to see how long it would track for, and I got as far as 5 minutes with just the tracking, and my stars were still mostly round!  I set the exposure time to 3 minutes so I could get more frames, and because that was long enough for the ZWO in these dark skies with this brighter target.  

Single 180s red channel frame, screen-stretched & zoomed in

The RGB frames looked a little out of focus, so partway through the night, I slewed over to a nearby bright star and checked the focus with a Bahtinov mask.  I tweaked it slightly, but it was very close.  I cinched down the focus lock a little tighter, slewed back to Centaurus A, and carried on.

Single 180s blue channel frame

While the ZWO was running, I set up my Sky-Watcher Star Adventurer with my Nikon D5300 and 70-300mm lens attached again, which I found some space for in the shed as well. Polar aligning this one was going to be harder -- I had no SharpCap to help me.  (I am working on putting together a rig for one of my guidescopes that will attach to the second camera screw on the Star Adventurer, which I could use both for polar alignment and for auto-guiding.  Yes, the Star Adventurer has a ST-4 port!)  I used my cell phone to get it pointed due south and get the elevation close to correct, but I couldn't see the Octans trapezoid in the polar scope still.  So I pointed it to the eastern horizon and then to zenith to do some drift alignment, which helped a bit.  I pulled the zoom on the lens back to something around 135mm, focused it, and then turned it to the glorious Eta Carinae Nebula.  I was able to get about 90s exposure times with minimal streaking, so I set it there and let it run.

Later in the night, I had a brainwave -- the Takahashi clamshell ring had a 1/4-20 tripod screw on the top!  So I took one of my ball heads and attached it to the top, and grabbed my Nikon D3100 and my new 35mm f/1.8 Nikon lens and got everything attached.  I aimed it up somewhere in the middle of the Milky Way (yes, up, overhead!!), vaguely toward M8 & M20, and took a 30-second test exposure at f/2.  I went to check on my D5300, and caught a quick glimpse of the D3100 image once it had completed and flashed onto the screen, and I froze.  I stood there for a moment, dumbfounded.  Did I just see what I think I saw?  I fumbled for the Review button, and it re-appeared on the screen. Holy McShitNuggets (were the actual words that came out of my mouth), it was incredible!

30s exposure pointing up toward the Milky Way with my Nikon D3100 and 35mm f/1.8 lens at f/2.

So I just left the camera pointed there, set it to 60s exposures at ISO-800 and f/2, and let it roll!

After all this work, everything was clicking away happily, so I went back to the lodge to warm up, take a break, and have a snack.  After the break, John, Beth and I wandered over to a lone 24-inch Dob beside another one of the cabins, which was being used by part of a large French group that was also visiting the Atacama Lodge.  Between people, we snuck in to observe the massive globular cluster 47 Tucanae.  Located about 13,000 lightyears away, it has about 10,000 stars packed into a ball about 120 lightyears wide.  It's large and bright enough to be easily seen naked eye just off the edge of the Small Magellanic Cloud, and is second only to the Omega Centauri cluster.  47 Tuc may even have a black hole at its center.  It spans an area of the sky that is wider than the full Moon by almost twice!  It was so spectacular in the large telescope that it prompted me to shout "Holy mackerel!" (yes that is what I actually said), which garnered some chuckles from the French.  

We walked up to the main field to nab a scope up there to use for the night, but the French had commandeered all of them.  So I went back over to my cameras to check on things.  Eta Carinae had gotten too low to continue imaging, and it was time to change targets on the Takahashi as well, so I took the opportunity to swap lenses between the Nikon D3100 and D5300 so I could put the longer lens on the mount that was tracking more precisely.  However, this proved to be too heavy for the Sky-Watcher AZEQ6 mount, for which I already had the counterweight at the bottom of the rail, and gravity overcame the RA clutch knob and the scope slipped over!  I caught it, and it was not like it was totally loose or anything, but it did mean that I had to start over with alignment.  I tried to tighten down the RA axis some more, but I couldn't get it any tighter.  Alain had said he'd look for a second counterweight in the daylight.  So I took the camera off, re-aligned (gotos weren't as good this time, however), and pointed it to my second target for the night, a galaxy in the southern constellation Pavo called NGC 6744.  

I started with the L channel this time, but it looked out of focus.  So I checked focus again with a Bahtinov mask, but it was still perfect.  I thought that maybe it was evenly-sided periodic error or something.

180s luminance image of NGC 6744, zoomed in

I pressed on anyway, since I wasn't sure what else to do.  Then I went over to my Nikon D5300 and set it up on the Small Magellanic Cloud with the 35mm lens.

Around 3:30 AM, I was petering out.  The long day and high altitude were making me extra-tired.  So I shut down the power to everything like Alain had asked me to, and got into bed around 4:15 AM.

It was a great night!  I got my imaging rigs rolling, the sky was incredible, and the Milky Way was simply mind-blowing.  We couldn't quite see any color, but the transparency might not have been the clearest that night due to the earlier clouds.  There were also some clouds still down near the horizon.  But the Large and Small Magellanic Clouds that appeared later in the night were easy to spot, as well as a large number of deep sky objects with averted vision.  I couldn't wait for the rest of the week!  We had five full nights under these skies!

[ Update July 21, 2019 ] 

I processed this image last weekend, but now that I finally got this log entry written, here is the Eta Carinae Nebula!

Date: 6 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Eta Carinae Nebula
Attempt: 1
Camera: Nikon D5300
Telescope: Nikon 70-300mm lens @ 90mm, f/4.5
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Subframes: 54x90s (1h21m)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 0
Flats: 0
Temperature: 33-36F

The stars came out a little bloated, and it turns out I was closer to 90mm than the 135mm-ish I thought I set it to, but isn't it a gorgeous region??  

Featured here is the Eta Carinae Nebula, which is a massive stellar nursery located in the constellation Carina, or "keel of the ship."  It's about 8,500 lightyears from us, and is 460 lightyears across!  From our perspective here on Earth, it's four times larger and is brighter than the famous Orion Nebula!  Unfortunately, however, you can only see it from southern skies.

It has a multitude of interesting stellar objects contained within.  One such object is the star Eta Carinae itself, which is an extremely luminous hypergiant star, weighing in at 100-150 times the mass of our Sun, and outputting four million times more light.  Due to its large mass, it is likely to go supernova in the near future ("near" in astronomical terms, of course). 

Immediately surrounding the star Eta Carinae is the Homunculus Nebula (probably the coolest nebula name ever, meaning "Little Man" in Latin, which sounds much less cool), which is the result of a huge outburst from Eta Carinae seen on Earth in 1841, which for a short time made it one of the brightest stars in the sky.  It's a very oddly-shaped nebula, and there are some very cool pictures out there of it!  

Also pictured here are the Southern Pleiades to the left, and the tighter open cluster NGC 3532 (also called the Pincushion Cluster, Football Cluster, or Wishing Well Cluster) to the upper right, as well as several other clusters.  

Here's how I processed it in PixInsight:

- Since I don't have any 90s dark frames at those temperatures, I skipped right to SubframeSelector
- Image scale: 8.97 arcsec/px
- Gain: 0.115 e/ADU
- Highest scoring frame: DSC_0050 (88.648)
- Debayered
- Registered with StarAlignment, with DSC_0050 as reference
- Stacked with ImageIntegration, using Linear Fit Clipping for rejection
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Color corrected with PhotometricColorCalibration
- Tried Deconvolution, but didn't like how it made the stars look
- Denoised with MultiscaleLinearTransform
- Stretched with HistogramTransformation
- Applied HDRMultiscaleTransform, 7 iterations, with lum mask
- Touched up with CurvesTransformation and HistogramTransformation

I'll probably go back and re-process this one and try to get the stars to not dominate the image as much.  We just discussed this on The Astro Imaging Channel last week, so I'll have to go back and re-watch it.

[ More update July 21, 2019 ] 

After I posted some of the screenshots of the Centaurus A galaxy, I realized the data didn't look as bad as I thought.  So I spent the later part of the afternoon processing that data.

I realized when I was filling in my documentation text file that somehow the gain got set to only 10 for this dataset, for which I have no dark frames.  I tried processing with gain 0 frames, but the calibrated light frames came out pretty much nuked of light.  So I went ahead and processed without calibration frames, but they turned out not to be that necessary, since I had my sensor cooled to -30C.  I didn't take any luminance data, although in a future re-do of this dataset, I might crop and re-scale this color data and add it to the luminance data I took of Centaurus A at the Texas Star Party.  It may or may not help, since Centaurus A was much lower in the sky -- and thus in the thicker, nastier part of the atmosphere -- but it might be worth a shot.

Anyway, here it is!

Date: 6 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Centaurus A
Attempt: 2
Camera: ZWO ASI1600MM Pro
Telescope: Takahashi FSQ-85ED
Accessories: Starlight Xpress filter wheel, Astrononik LRGB Type 2c 2-inch filters
Mount: Sky-Watcher AZEQ6 (Alain Murray's)
Guide scope: N/A
Guide camera: N/A
Subframes: R: 28x180s
   G: 26x180s
   B: 10x180s
   Total: 64x180s (3h12m)
Gain/ISO: 10 (not sure how that happened)
Acquisition method: SequenceGenerator Pro
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 0
Flats: 0
Temperature: -30C (chip)

This might be only my 'official' second attempt, but I had tried to image it before but ran into other issues that led me to not keep that data.  So I'm happy to finally have an image of this cool galaxy!  It's not only cool to look at in its weirdness, but its weirdness has made it an interesting target of study.  Centaurus A is somewhere between 10-16 million lightyears away -- no one is quite sure.  It doesn't fit cleanly into any established galaxy category, and its odd shape is probably a result of a galaxy merger.  At the center of that galaxy is a 56-million-solar-mass black hole that is blasting out jets that move at half the speed of light and emit brightly in x-ray and radio.  They extend out to a million lightyears!  Very cool galaxy to look at.  It's also on the top-5 list of the brightest galaxies in the sky as seen from Earth, so it makes a good visual observing target.

[ Update August 8, 2019 ] 

Still plowing through Chile datasets -- here's the Magellanic Cloud!  It turned out to be just a hair out of focus, so the quality isn't that great, but here it is anyway.

Date: 6 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Small Magellanic Cloud
Attempt: 1
Camera: Nikon D5300
Telescope: Nikon 35mm f/1.8G @ f/2
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 28x90s (42m)
Gain/ISO: ISO-1600
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 20 (28F)
Flats: 0
Temperature: 32-35F

I did try to apply some deconvolution to see what sharpening could be done on the SMC, and with a small number of iterations, it helped a tiny bit.  I did try MaskedStretch for stretching the image, but it blew out the small pink and blue halos around the stars, which I didn't like.  So I re-stretched it myself with HistogramTransformation instead.

Here's the whole process:
- No darks, calibrated lights with pre-made superbias using ImageCalibration
- SubframeSelector:
- Scale: 23.07 arcsec/px
- Gain: 0.115 e/ADU
- Highest-scoring frame: DSC_0162 (85.313)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear Fit Clipping
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Denoised with MultiscaleLinearTransform
- Color corrected with PhotometricColorCalibration
- Applied Deconvolution using DynamicPSF, range_mask-star_mask, 10 iterations
- Tried MaskedStretch, but stars got pink and blue halos, so I stretched it myself
with HistogramTransformation
- Tweaked with CurvesTransformation
- Applied HDRMultiscaleTransform, 9 iterations

[ Update August 15, 2019 ] 

Still chugging through Chile data!  Being in the middle of a move makes finding time and energy to do this difficult!  But I finally had some chill time to work on it.  

I processed the stack of the Milky Way I took with the 35mm lens piggybacked on the Sky-Watcher AZEQ6 mount -- the "Holy McShitNuggets" dataset -- and the result was truly excellent!  There was also almost zero drift across the whole time of the stack, which was awesome and gave me nice round stars.

Date: 6 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Milky Way
Attempt: 9
Camera: Nikon D3100
Telescope: Nikon 35mm f/1.8G @ f/2
Accessories: N/A
Mount: Piggyback on Takahashi FSQ85ED, on Sky-Watcher AZEQ6
Guide scope: N/A
Guide camera: N/A
Subframes: 39x60s (39m total)
Gain/ISO: ISO-800
Acquisition method: Intervalometer
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 0
Biases: 0
Flats: 0
Temperature: 31-35F

I just can't get enough of that Milky Way!!  There are several interesting things here.
- The super bright thing on the right is Jupiter
- In the lower right is the Rho Ophiuchi complex, which I've recently shared closer-up images of. The brighter yellow-orange star is Antares.
- The dark upside-down-U-shaped nebula to the left of Jupiter is the Pipe Bowl Nebula, a giant molecular cloud
- The two fuzzy red regions in the center of the image are two emission nebulae - NGC 6357 on top, and the Cat's Paw Nebula on bottom
- Up above NGC 6357 is open cluster M7, Ptolemy's Cluster
- In the lower left of the image, the other red nebula region is emission nebula IC 4628, surrounded by stars that are part of the Trumpler 24 open cluster

...and much more, of course!

This one was a pretty quick job.  Being one-shot color and not having issues or light pollution helped!
Here's the PixInsight processing:
- No darks or biases b/c I don't have a library for my D3100
- SubframeSelector:
- Scale: 25.9 arcsec/px
- Gain: 0.115 e/ADU (not actually measured, just borrowed from D5300)
- Debayered
- Registered with StarAlignment, using highest-scoring frame was reference
- Stacked with ImageIntegration
- Combination: Average
- Normalization: Additive
- Pixel rejection: Linear fit clipping
- Tried skipping DynamicBackgroundExtraction and did PhotometricColorCalibration instead, since there's pretty much no light pollution and most of the image is Milky Way anyway
- Denoised with MultiscaleLinearTransform, with luminance mask
- Stretched with MaskedStretch
- Tried with target background 0.15, interesting result, but not a huge fan
- Tried again with target background 0.10
- Tried again with 0.05, but too low, so did 0.08 - let me try some curves on that
- Adjusted with CurvesTransformation
- Applied the DarkStructureEnhance script

I wanted to have nice contrast between the bright and dark areas, and show just the insane number of stars in the bulge.  I also wanted the dark nebulae to stand out nicely.  But I didn't want it to look too hard or electronic either -- kind of softer, like how it might appear to our eyes if they were more sensitive.  As with many of my images, I'll probably mess around with it more in the future.  But I am quite pleased with this one!