Showing posts with label Star Tracker. Show all posts
Showing posts with label Star Tracker. Show all posts

Friday, July 31, 2020

#379 & #380 - Saturday & Sunday, July 18-19, 2020 - Family camping, auto-guiding the Star Adventurer, and my new trailer!!

In the midst of COVID, time off has been pretty limited, mainly because all of the places one can go on vacation to are shut down in one way or another.  All of the star parties I was planning on going to this summer were cancelled, with the main event I look forward to every year being the Texas Star Party.  After a shelter-in-place spring break, with everything closed or cancelled, I haven't had any vacation time.  So I decided to create some!  I drove home to Spokane, WA to visit my family for a little over a week.

Drive home


It's about a 15-hour drive if you don't include stops, so I took it over two days.  I spent the first night in a town called Redmond, OR, which is just north of Bend.  It's a nice little town with a lot of new construction.  As soon as I pulled in, I began scouting out possible locations at which to shoot Comet NEOWISE!  It didn't take me long to find a good spot: there was a walking trail along a canal that runs through town, and a couple hundred feet down the trail, I found a spot that peaked through the trees to the right altitude & azimuth that the comet would be at later that evening.  I mentally marked the spot, then got some dinner and hung out in the hotel room until dark.

About a half hour after sunset, I took my DSLR, a couple lenses, and my tripod across the street and down the trail to the spot I'd found earlier.  It was off the road, and I hoped the people in the houses along the trail wouldn't be too freaked out by a red-lamp-wearing shadowy stranger lurking on the trail, haha.  I had to scoot down the trail a bit further to avoid disturbing a particularly loud dog.


I wasn't sure how soon after sunset it would be visible, so I got comfy sitting on a rock and waited.  And waited.  And waited.  

Finally, at about 9:45 PM (so about an hour after sunset), I thought I spotted the comet out of the corner of my eye.  I put my 18-55mm lens on and took a shot -- and there it was!

Nikon D5300, 18-55mm lens @ 40mm, 3s, ISO-800, f/5

As the sky slowly darkened, I got the lens focused, and took a series of 6-second exposures at 55mm focal length that I would stack later on.  I took 62 of them, and then swapped out to my 70-300mm lens, set it at 70mm, and took another series of 5-second exposures (adjusted to minimize star trailing).  Next, I set it to 105mm and took a bunch of 5s exposures, although the stars trailed a tiny bit.  And finally, I did a nice zoomed-in 200mm series at 1.3 seconds.

Due to the high rate of field rotation that far north, the shorter-focal-length images had steady stars near the comet nucleus, but pretty streaked stars farther away, showing obvious rotation.  But the 200mm final image has nice, steady stars -- I didn't even have to process it twice to get steady-stars and steady-comet, since the comet was moving relatively slowly against the background of stars.

Date: 15 July 2020
Location: Redmond, OR
Object: Comet C/2020 F3 NEOWISE
Attempt: 2
Camera: Nikon D5300
Telescope: Nikon 70-300mm lens
Mount: Tripod
Exposure: 49x1.3s, f/4.8, ISO-5000

I finally called it quits at about 10:30 PM, since I'd been out there for quite a while already, and needed some good sleep to finish the drive the next day!

Highway 97 through Oregon is a pretty lonely highway, and I've never seen a cop on it, so I usually speed through Oregon at a good clip.  I managed to arrive home on Thursday afternoon just before my mom headed off to work.  My sister and her husband are currently living at home as well, with one out of work due to COVID, and the other working only part-time.  So I had somebody to hang out with while my parents were at work!  They were busy doing other things though, so I just took a seat in the swinging chair on my parent's amazing front porch with a glass of lemonade and enjoyed the great weather until my dad got home early.


Camping trip


My dad took an extended weekend off of work and the five of us, plus my grandparents, took our two trailers up north to my dad's boss's property for a camping weekend.  It was spitting distance from the Canadian border, and although I brought my passport in case we headed up that way, I'm pretty sure Americans aren't allowed into Canada right now!  Crazy to think.


The family of my dad's boss have a whole house built up there in the woods along the Columbia River, as well as a giant shop.  The shop has some sleeping and living quarters, but everyone wanted to feel like we were camping, so my parents slept in their trailer, grandparents slept in their trailer, and my sister & bro-in-law slept in their tent.  My parents had told me not to bother bringing up my tent because of the sleeping area in the shop, but I didn't want to sleep there by myself!  So I cleared out the back of my grandparent's SUV, laid down the seats, and slept in there on my air mattress (which I did bring just in case).  It was a pretty tight squeeze, but I've been meaning to test out car-camping, so it was kind of fun!

We did some lounging around and some fishing in the evening, and while the fishing was going on, you can probably guess what I was doing -- setting up gear!  Since I drove up instead of flying, I could bring up whatever gear I wanted, but I decided not to bring a whole telescope rig because that far north, astronomical darkness only lasts for about three hours.  So instead, I brought my Sky-Watcher Star Adventurer, ZWO ASI294MC Pro, and 55-200mm camera lens that I had attached to my Celestron AVX mount in my backyard.  Since it was quite dark up there -- Bortle 2-ish -- I wanted to swap out the Orion SkyGlow filter for just a UV/IR cut filter.  The Orion SkyGlow filter is SCT-threaded, so I needed a different solution.  Working an M48-threaded filter into a camera lens setup is tricky, so I wound up putting my 1.25" Astronomik Luminance filter inside a manual filter wheel I haven't used in a white, which was nearly the same thickness as the SkyGlow filter for back-focus purposes.  While I did measure it with my calipers, I didn't get a chance to double-check that it would come to focus, so I brought along some extra spacers and adapters just in case.  (Different filters have different indices of refraction, which move the focal point around by a couple of millimetres).  

In addition to all this, I brought a couple extra things to do another experiment I've been wanting to do for quite some time, which was auto-guiding the Star Adventurer.  It has two camera connection points on it, and I finally had acquired all the adapters I needed to put my Orion 50mm mini-guider attached to a QHY5 guide camera on it.  The Star Adventurer uses ST-4 guiding, not USB, and only the RA axis is motorized, but my expectation was that it would at least help clean up the tracking enough to allow for longer exposures, especially if I was well-polar-aligned.  ST-4 guiding works by plugging the guide camera into your computer via USB, running PHD2, choosing "On-camera" for the mount, and then plugging the camera via ST-4 cable (the wider telephone-looking one) into the mount.  So PHD2 doesn't talk directly to the mount, but rather sends the command through the camera to go to the mount.  It's an older, and largely obsolete, method of autoguiding (pulse guiding is much better), but it still works for mounts that don't support USB guiding!  The major downside to ST-4 guiding is that because PHD isn't talking to the mount, it doesn't know what the telescope's declination is (which affects the calibration and the length of pulses it needs to send), so you have to tell it yourself, and re-calibrate every time you change targets (although I think Sequence Generator Pro can actually handle this).  But since the Star Adventurer isn't a goto mount, just a "dumb tracker," I'm only doing one target at a time anyway, so it's a non-issue.

There was power up there, but I forgot to bring the AC-DC adapter for the cooler on my ZWO camera, so I just ran that off the battery.

The back deck was pretty shaky, but there wasn't a good spot on the pavement to see the North Star from, and the sprinklers were running on the grass (yes, they had a lawn, and yes, it had sprinklers...sheesh!)  So I just told everyone to stay off the patio after dark.

Setup actually went pretty smoothly: I used the Polar Alignment app on Android (there's something like it on iPhone too I think) to plant the North Star at the right place on the "clock" in the polarscope for the time and date; did some star-hopping in the red-dot finder I had for the ZWO camera to land approximately where I wanted to image (the Elephant Trunk nebula up in Cygnus; it was dark enough that I could hop to the Garnet Star at the edge of the nebula with ease, and then guesstimate from there where to center the camera); set up PHD2 to guide in just RA and got it calibrated on the first try, and then just let it run once I saw the first 3-minute frame come down looking pretty good (after sitting very still).  I couldn't check on progress remotely because there was no cell signal up there to create a wifi network to remote into my computer from, and I didn't want to rattle the deck by walking on it over to my computer, so I just let it be and crossed my fingers.  Most of the frames turned out pretty well actually, and I imaged the same spot the next night as well.

One of the benefits of camping so far north (48N latitude) was that Comet NEOWISE was quite high in the sky, sitting at 22 degrees high at 9:45 PM, and still 12 degrees high when it was nice and dark at 11:45 PM.  My grandparents were very excited to see it through a break in the trees; it was fairly obvious naked-eye still that night, and looked great in binoculars and in the camera.  I think the rest of my family got a kick out of seeing it as well.  And I got some nice shots!

Nikon D5300, Nikkor 35mm f/1.8G lens, 20s, ISO-6400, f/2.2
We had the lights from the town of Trail across the border to the north, but overall it was quite dark!

My dad and brother-in-law managed to catch only two walleye, but we prepared them and cooked them up over the campfire for some delicious fried dessert bites.  

My sister Mary's turn with the rod

Parents & grandparents at the fire pit

The weekend came to a close all too soon on Monday, and we packed up and headed back to Spokane.  It was a really nice, relaxing weekend!  And then I had the rest of the week to process my images, since I brought my laptop with me.

Imaging Results


The Elephant Trunk Nebula image came out pretty decently given that I just used a color camera and no narrowband!  I was a little bit off-target in my aiming, but actually quite close for doing it by hand!

Date: 18, 19 July 2020
Location: North of Northport, WA
Object: IC 1396 Elephant Trunk Nebula
Attempt: 4
Camera: ZWO ASI294MC Pro
Telescope: Nikon Nikkor 55-200mm f/4-5.6 @ 200mm, f-something (toothpicks)
Accessories: Astronomik L Type 2c 1.25" filter
Mount: Sky-Watcher Star Adventurer
Guide scope: Orion 50mm mini-guider (ST-4)
Guide camera: QHY5
Subframes: 18x180s (54m)
Gain/ISO: 120
Acquisition method: Sequence Generator Pro
Stacking program: PixInsight 1.8.8-5
Post-Processing program: PixInsight 1.8.8-5
Darks: 100
Biases: 0
Flats: 0
Temperature: -10C

Now, the actual Elephant Trunk is hard to see -- if you start at the Garnet Star (the bright yellowish one on the left), and scoot directly to the right, passing over the U-shaped dark nebula, you can just see the formation of the tip of the Elephant Trunk before you hit the next streak of dark nebula to its right.  (I recommend clicking the image to blow it up to see it).  I got some red nebulosity, nice dark nebula, and pretty good-looking stars for this camera lens!

I also ran around with my DSLR and 35mm f/1.8 lens to get some nice Milky Way shots!

Nikon D5300, Nikkor 35mm f/1.8G lens at f/2, 8s exposure, ISO-6400
That's Jupiter peaking its face up from behind the hills there!

I also attempted some panoramas, which I haven't processed yet.

At long last, the AstronoMolly-Mobile!


Back when I used to camp at my astronomy club's observatory grounds when I lived in the Midwest, I was usually one of the only tent campers -- most of the rest of the gang who came out had those fancy trailers.  My grandparents lived in an RV for about 20 years after my grandpa's retirement, and my parents started trailer-camping a couple of years ago, but I am still perfectly happy tent camping.  For regular camping trips, that is -- tent camping becomes more difficult when doing astronomy.  This is largely because of getting adequate sleep; it's hard to sleep in when it gets very bright and very hot early in the morning.  (Or very cold at night too, in some places!)  And while I've been camping more times than I can count throughout my life, 7 nights tent-camping at someplace like the Okie-Tex Star Party sounds kind of not-fun.  And now with bathrooms closed at campgrounds and other public places due to COVID, it's even harder.  It is finally time to make a purchase I've been planning for a couple of years now: a trailer!

So I drive a 2017 Ford Escape, the 4-cylinder 2.0 L Ecoboost variety, which is in the compact SUV class.  Most compact SUVs can only tow 1-2,000 lbs, but the Escape was built on a truck chassis, and paired with the Ecoboost turbo, it's rated to tow 3,500 lbs.  Now, since it is only a 4-cylinder, I was pretty sure that 3,500 lbs was not going to do very well, so my plan was to stick somewhere sub-2200 lbs dry.  There are lots of soft-sided campers that fit the bill, but I didn't want soft-sided (both for protection from wildlife and holding in heat/cool).  I also wanted a toilet of some kind, and there were some hard-sided A-frame-type campers I was looking at as well that had cassette toilets and pop-up wetbath walls.  There are also plenty of small trailers out there, but most are 2500+ lbs, with probably too much frontal area to tow comfortably in my Escape (the manual says to keep it below 30 square feet).  

In my internet searches, particularly when I was looking for user experiences in towing with my car type, a brand I hadn't come across previously was mentioned quite a lot: Nucamp T@bs.  They're little trailers, but not pop-up campers that I had been looking at before.  After seeing what was available at the local RV dealerships, my parents and I went to RnR RV, which had a couple small trailers at their Liberty Lake location, and a couple more at their North Spokane location.  We went to Liberty Lake, since it was a faster drive, and my grandparents had bought from them before.

On the showroom floor was a T@b 320 S, which was little but packed with features, and only weighed 1900 lbs!  It was perfect.  The dealer took me out to the lot to look at a used version and another light trailer, but when we came back in, that T@b had been sold out from under me!!  The used one was only one model year old, 2019, and was nearly the same price as the new one (they hold their value pretty well, like Subarus).  So the dealer looked up what was available at their other location, and lo and behold, there was another T@b 320 S.  But, even better -- it was this incredible white and red color!  Super cute :D And astronomy-red!  It was pricier than the more boringly-colored one there because it had the Boondock package, but we convinced him to lower the price to nearly-match the one there.  It was terrifying and exciting, but it ticked nearly all of the boxes of both what I needed and what I wanted, so I bought it! :D  They pulled it down to the Liberty Lake location, and I came back later in the week to pick it up, do the walkthrough, and have my car modified (replaced the 4-pin electrical connector with a 7-pin and added the electronic braking system control unit).  It is perfection :D



It took me several attempts to get it backed mostly-straight into my driveway, but I did it!

The table is fully-articulating -- it moves in a circle, can be pushed and pulled to one side or another, and raises and lowers.  It also can be removed and re-attached outside on the side of the trailer.
The back of the couch-seat there folds down into a space where, if I set up slightly diagonally, I can set up a place to sleep without having to take the table out, and there's still room to sit on either side of the table!

That's a little TV there on the left, with air conditioning and heat/electricity/hot water controls above it.
The kitchenette includes a sink, two-burner gas stove, and 3-way fridge (AC, DC, and gas).
There are four windows that all open outward, and each has both a draw-down screen and draw-up privacy shade.  The door also has a little porthole window that has its own privacy screen.

Yes, it has a toilet and a shower!!  I can't quite stand in the shower, so it'll be a seated shower whenever I do take one in there.

I've already had a bunch of my neighbors come by to admire it!  It's just so darn cute!
As far as other stats go, it has a single propane tank and battery on the front, a reversible, multi-speed (and honestly pretty quiet) fan on the roof, a tankless water heater, no outside storage (but I'll be strapping a bin to the front to hold my hoses and electrical cables), a 10-gallon freshwater tank, 10-gallon graywater tank, and 5-gallon blackwater tank, AC power connection (30 amp), solar power connection (to trickle-charge the battery), racks on the back for other outdoor gear, and LED lights on the front and back for illuminating your site.  Also, the cabinets are actual wood, made by the Amish.  (The trailer included a picture and signed card from the crew that made them!).  The outside is fiberglass.  

Driving it home from Washington back to California went pretty well, actually.  I had little trouble getting it on my hitch and all hooked up by myself the morning I left (thanks largely to my backup camera!).  I don't really feel the trailer on city streets, and didn't start to feel it on the highway until about 60 mph, when the drag became great enough to feel.  (The super-off-road tires I'm sure don't help with that situation!).  Downhills were no sweat with the electronic braking system, but uphills made the motor work a little harder.  I eventually had to just go 50-55 on uphills to keep the motor below the 4-5,000 rpm range.  Engine temperature never left normal, but my gas mileage sure did suffer!  I averaged about 12.5 mpg coming over the Sierras and then through the vineyards and desert-y parts of CA on the way back to the bay on I-5.  So it took a little longer to get back, but really not too bad.  (Although I definitely won't be going 80 mph on that interstate through Texas to the Texas Star Party next year though!).  It only fishtailed a bit once when the road was a little rough and a gust of wind caught me by surprise, but it was easy enough to regain control by just letting my foot off the gas and not moving the steering wheel.  I did a little reading, and it sounds like I can also tap the braking system control to apply the trailer brakes a bit to bring it back under control.  

All in all, it's the perfect trailer for singular me and the many astro-camping trips and star parties in my future!

The new AstronoMolly Mobile Observatory!




Table of Contents

Thursday, August 8, 2019

#198 - Wednesday, July 10, 2019 - Last Dark Night of the Atacama

This morning, I was only able to sleep in until 10:30 -- it was too warm inside, and I became worried about whether the cameras I had left running on my Sky-Watcher Star Adventurer would have moved far enough to hit the mount or something.  So I got up and went to check -- all was well.  I shut off the power, put the batteries on their chargers, and grabbed my Nikon D5300 off of the mount for use later in the day on our adventures.

We tried again to visit the Valle de la Luna, this time arriving before 1 PM.  It was a beautiful park for not having a single living plant!



The moon over the Valley of the Moon!

One of the stops along the way was to a hiking trail that went up to the top of some part-sand dune, part-rock hilltops, as high as 8400 feet above sea level!  By the time we got to the top (after several stops to rest), it felt like I had just run a 5k!  But the view was incredible, and standing on a particularly tall rock made me feel like I was standing on top of the world.


We hit a few more stops along the way, including some old salt mines.


All of the white stuff in the rocks is salt.

At the end of the road was the Tres Marias rock monument, which was really cool looking.  I had to wonder how it was formed!


The miners would pray here for safety.

On the way back to the Atacama Lodge, we stopped for gas in San Pedro de Atacama, at their one Copec gas station that was in a really weird and rather hard-to-find spot.  It also had a long line.  We decided to wander around town for a bit and hit up some ice cream and pick up some gifts.  We also walked through a really old church that was built sometime before 1557!  The ceiling was made of dried cactus, which was really cool.


We drove back to the Atacama Lodge and watched the sun set. I set up my Nikon D3100 to do a day-to-night timelapse, and I got the cameras booted up on my Sky-Watcher Star Adventurer.  I pointed the Sony a7s with the Rokinon 135mm f/2 lens I was borrowing from the owner of the Atacama Lodge, Alain, over to the Rho Ophiuchi complex, which I've tried to image several times from various locations with varying levels of success.  I had to position the camera carefully so that I wouldn't pick up Jupiter's camera-saturating glow.  

Also attached to the Star Adveturer was my Nikon D5300 with my 70-300mm lens, and I was going to do M16 & M17 up in Sagittarius.  However, it was too close to where the Sony was pointed, and the cameras were hitting each other.  So I just picked a spot further south in the Milky Way and figured I'd see at least something interesting there.  

Once that was all set up, I went back to the cabin to have some dinner (leftovers we were trying to finish off), and I got my stuff most of the way packed up for departing Chile the next day.  :(  I went to bed at 9:45, and the plan was to sleep till 2, get up and do some observing, and hit the road by about 4:45 to drive to Calama to catch our flight out.

At 2 AM, I dragged myself out of bed, got dressed, and finished packing.  I went up to the rolloff shed and packed up my cameras and Star Adventurer as well, and then went and joined my travel companions John and Beth at the telescopes.  Alain was just putting the finishing touches on a behemoth 45-inch Dobsonian he'd spent the last few years building, and we were hoping to get first light through it!  We helped him collimate it, although we couldn't quite reach collimation -- he would need to move the focuser hole inward a bit toward the primary (a task he'd set about doing soon).  But it was close enough for first light.  We brought the tall ladder over, and with each of us taking turns holding up the scope since the counterweights weren't quite right yet, we turned it to the obvious choice of first-light targets: the incredible Tarantula Nebula, in the Large Magellanic Cloud.  The stars weren't quite pinpoint because of being not quite in collimation, but what a view!  


Now we can say that we got to experience first light on the largest telescope in South America for use by amateurs!  :D  We also took a look at 47 Tucanae, the giant globular cluster.  I wish we could have seen that with this thing collimated!  Oh well, next time :)

We got the car loaded up, bid farewell to Alain, and drove an hour up to Calama, where we would fly out to Santiago.  Then my flight back to the states was later that night, at 8 PM.  The plan was to run around Santiago for a few hours, and then I would head to the airport to catch my flight home.  Due to a miscommunication, John and Beth's flight was the next day, but I was glad to be leaving earlier.  I was ready to head home!

All in all, Chile was an incredible adventure, and I had a great time.  The solar eclipse and the incredible dark, clear skies at the Atacama Lodge were obviously the highlights of the trip!  I had 21 deep sky datasets to process when I got home, plus numerous timelapse videos and single-frame nightscapes.  Not to mention all of the awesome daytime photos of all of our other adventures!  I also got to do a ton of visual observing, which was really rewarding, especially because things weren't just dim fuzzies, but really exciting to look at under those skies!  

I'll definitely have to go back!

[ Update August 5, 2019 ] 

Rho Ophiuchi Complex

I got the Rho Ophiuchi image processed, and HOLY COW did it come out well!

Date: 10 July 2019
Location: Atacama Lodge, San Pedro de Atacama, Chile
Object: Rho Ophiuchi region
Attempt: 7
Camera: Sony a7s, astro-modified (Alain Maury's)
Telescope: Rokinon 135mm f/2.8
Accessories: N/A
Mount: Sky-Watcher Star Adventurer
Guide scope: N/A
Guide camera: N/A
Subframes: 1: 324x30s (2h42m)
2: 58x30s (29m)
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: 35-45F

Yes, that is only a half-hour of data! :O This image was really exciting to process. I literally got tears in my eyes a bit when it emerged from DynamicBackgroundExtraction. Here's why...


I wasn't sure how much of the nebula was really there with those short exposures, but the Sony a7s is so dang sensitive that I couldn't go much longer without saturating. It turned out to be just right! And I finally got some of that brown color in the dark nebula that I've seen others get but hadn't been able to achieve myself.

The first version of this one didn't come out quite as nice.


The stars got fatter, and the nebula regions weren't as well-defined. The main reason for this was that the focus slipped on the lens not very far into the run, but I tried stacking them all anyway for the sake of SNR. With all of the frames, I had 324x30s, or 2h42m of data. But then I decided to see how it would look with the much smaller number of in-focus frames -- only 58. The result was much better, and the SNR didn't seem to suffer (the lack of light pollution helped, and the apparently low noise of the Sony camera).

Another thing I tried was a new PixInsight process for me -- MaskedStretch. I went looking through Warren Keller's book Inside PixInsight for a section on processing dark nebulae that someone mentioned to me was in there, but wasn't able to find it (at least, not with a couple of quick looks). So I just looked through the section on stretching, and decided to give it a try. It performs a series of stretches, and the end result has the peak of the histogram exactly between the black point and the gray point. Since none of the peak was pushed past these two points, the image was still somewhat dim, so I brought it into CurvesTransformation and brightened it up from there. Then I did a few more steps, and got an end result I was very pleased with!

Here's the steps for the shorter-stack, in-focus version:
- Started with SubframeSelector because no darks/biases:
     - Scale: 12.82 arcsec/px
     - Gain: 0.316 e/ADU
     - Highest-scoring frame: DSC00227 (92.349)
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
     - Combination: Average
     - Normalization: Additive
     - Rejection: Linear Fit clipping
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Corrected color with PhotometricColorCalibration
- Stretched with MaskedStretch
- Stretched the rest of the way with CurvesTransformation
- Adjusted curves some more
- Denoised with MultiscaleLinearTransform
- Applied DarkStructureEnhance
- Applied SCNR to help kill leftover green tint
- WoWeEEE

So happy with this one! And a great example of what powerful post-processing does for you.

Milky Way

My random positioning of my 70-300mm lens at 70mm pulled in a nice area of the Milky Way! Included in the scene are M8 Lagoon Nebula and M20 Trifid Nebula, M6 Butterfly Cluster, M7 Ptolemy's Cluster, the Pipe Bowl dark nebula, and more. Also, in one of the frames, I caught a nice meteor! So after processing the image the first time, I took the stacked image, added the single frame with the meteor to it using PixelMath (I'm sure there's a more elegant way to do this), and then applied the same processing steps (mostly). It came out nice! Even though there was a lot of moon in the background in the subframes.
Date: 10 July 2019 
Location: Atacama Lodge, San Pedro de Atacama, Chile 
Object: Milky Way 
Attempt: 12 
Camera: Nikon D5300 
Telescope: Nikon 70-300mm f/4-5.6G @ 70mm, f/4 
Accessories: N/A 
Mount: Sky-Watcher Star Adventurer 
Guide scope: N/A 
Guide camera: N/A 
Subframes: 54x120s 
Gain/ISO: ISO-1600 
Acquisition method: Intervalometer 
Stacking program: PixInsight 1.8.6 
Post-Processing program: PixInsight 1.8.6 
Darks: 58 (44F) 
Biases: 21 (44F) 
Flats: 0 
Temperature: 38-46F (mostly low-mid 40s) 

I tried MaskedStretch on this one too, but it blew out the blue halos around the stars from the slight chromatic aberration of the lens, so I did the stretch myself in HistogramTransformation instead. I still got some blue halos, but not as bad. Then I took it over into Photoshop and used one of Noel Carboni's Astronomy Tools for Photoshop to reduce the blue halos.

Here are all the steps I did:
- Created master bias with ImageIntegration, then Superbias
- Calibrated darks with superbias using ImageCalibration
- Created master dark with ImageIntegration
- Calibrated lights with master dark & superbias using ImageCalibration
- SubframeSelector:
     - Scale: 11.54 arcsec/px
     - Gain: 0.115 e/ADU
- Debayered
- Registered with StarAlignment
- Stacked with ImageIntegration
     - Combination: Average
     - Normalization: Additive
     - Pixel rejection: Linear Fit Clipping
- Added meteor frame to stacked image with PixelMath
     - Tried averaging the two, but it cut the meteor brightness in half (of course)
- Cropped with DynamicCrop
- Applied DynamicBackgroundExtraction
- Denoised with MultiscaleLinearTransform, with luminance mask
- Color corrected with PhotometricColorCalibration
- Tried MaskedStretch, but blue star halos got pretty bad
- Stretched with HistogramTransformation
- Tweaked with CurvesTransformation
- Sharpened with MultiscaleLinearTransform
- Adjusted some more with CurvesTransformation
- Reduce Blue Halos in Photoshop

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.