#457 - Monday, December 21, 2020 - Conjunction Junction

 It was one of the most-talked-about astronomical events of the year -- the Great Conjunction of Jupiter and Saturn!  The two heavenly bodies appear close to each other from our perspective about every 20 years, but are not usually close enough to be a big deal.  The last time, in May 2000, they were 68.9 acrmins apart, or a bit more than two full Moons side-by-side.  This year, however, they would draw as near as 6 arcminutes apart -- nearly on top of each other.  The last time they were this close was back in 1623, in the days of Galileo; however, the two planets were close to the Sun, so it is likely that nobody witnessed it.  Before that, there was the Great Conjunction of 1226, in the time of Genghis Khan, which was visible at night.  Luckily for us young folk, the next close pass of Jupiter and Saturn will occur in only 2080, which some of us may live to see.  (For more info, see this article in Scientific American).

I had put the event on my calendar some time ago, probably back in 2019, and set reminders for myself so I could prep.  Of course, with all the chatter on the Internet, how could I forget?  I started working up a plan back in the fall, and in the days leading up to closest approach, I did some test runs.

About a week before the actual night of closest approach, I saw on SkySafari that the two planets were close enough to catch in my refractor, and since it's positioned in such a way that I could see the two shortly after sunset before they disappeared behind the tree, I nabbed a video on my one-shot color ZWO ASI294MC Pro camera and produced an image.

Date: 15 December 2020

UTC: 16 December 2020 01:34

Location: East Bay area backyard, CA

Object: Jupiter & Saturn, near conjunction

Camera: ZWO ASI1294MC Pro

Telescope: Takahashi FSQ-106N

Accessories: ZWO EAF focuser, Astronomik CLS-CCD 1.25-inch filter

Mount: iOptron CEM40

Exposure: 15ms (Jupiter), 150ms (Saturn)

ISO/Gain: 120

Acquisition method: SharpCap Pro

Stacking program: PIPP

Processing program: Photoshop CC 2021

I couldn't get AutoStakkert to align the frames because of the two separated targets, so I just had PIPP (Planetary Image Pre-Processor) sort them by goodness and I pulled the best frame from each of the two videos (one for Jupiter and one for Saturn, because of the two different exposure times needed) and combined them in Photoshop.  So it's a little blurry, but still cool to see them so close!

Gear

Because they were only going to be six arcminutes apart, I was going to be able to throw a lot of magnification at them and get a nice shot.  I decided to use my Celestron 8-inch Schmidt-Cassegrain, which has excellent performance on planets.  It currently is seated on my Paramount MyT, and I've been using it for deep-sky imaging all year.  Unfortunately, the Paramount was on the wrong side of my backyard to be able to see the conjunction, which was low in the western sky -- my enormous lemon tree blocks the view.  So I went old-school and pulled my Celestron NexStar SE alt-az mount out of the garage, which I primarily use for outreach (back when we could do that in-person) and for planetary imaging that I can't reach from my backyard.  The nice thing with using an alt-az mount for this transient events is that I don't have to polar align it or even have a decent alignment model -- I can just plop it down, point it at a planet, and say "track this," and it does a decent-enough job for the short exposures of planetary imaging.  

For the camera, I decided to use my monochrome CMOS camera, my ZWO ASI1600MM Pro.  I always get better results on it, and I can get higher-resolution images from it because a) the pixels are smaller and b) every pixel is used instead of interpolating 2x2 quads of pixels to produce color images the way one-shot cameras do.  The downside is that I have to be quick on the draw, changing filters and nabbing frames as fast as possible to get all three colors before Jupiter rotates appreciably, which is a timespan of about 90 seconds.  Luckily, I'm quite practiced at it.  I used my Astronomik RGB filters in my ZWO electronic filter wheel, and I removed the focal reducer for maximum resolution and magnification.  

The laptop I typically use with my primary rig is an old Lenovo from 2012, named Feynman, that I refurbed with a solid-state hard drive.  It performs quite well, but only has USB 2.0, which limits my frame rate to about 1 fps full-frame.  My other data acquisition machine is my Microsoft Surface 3 tablet, named Messier, which is also getting on in years and has been slowing down significantly, even after an operating system clean re-install.  It has USB 3.0, but I knew I wouldn't be able to livestream from it, which I was planning to do with Explore Alliance.  So I decided to spin up my performance laptop, named Cherenkov, which is an MSI I bought myself for Christmas in 2018 for grad school use and star party on-site image processing use.  I moved my table over, and brought out a light so I could be seen on camera, as well as my webcam and mic (the built-in ones on this laptop are terrible).  I got SharpCap Pro and all my camera and filter wheel drivers installed.

Test Drive

I tested out the whole setup on December 18th.  After a couple of issues with not having all the drivers I needed installed, I got everything rolling, and got my Streamlabs OBS settings set up how I wanted.  Once it finally got dark enough to spot them, I got the mount aligned on them and started imaging.  Everything went pretty smoothly -- I have a lot of experience in getting set up now!  

Jupiter and Saturn were already close enough to image at prime focus, without the focal reducer!  I had some trouble processing the images though still.  I even used PIPP to do some pre-alignment, but still couldn't quite get it to go.  I hoped that it would be easier once they were closer together.

The Great Conjunction

The night finally arrived!  I had actually delayed by travel home for Christmas when I bought my plane ticket back in October so I could be at my house for the conjunction.  Dedication :D

There were some clouds in the west before sunset, and I was getting worried.  But they were kind of patchy, so I hoped to at least manage some shots through them.  Fortunately, they cleared out after sunset!  Then it was just a waiting game for Jupiter to become visible so I could align the mount.  I had moved it around since the test drive, so I had to re-align it.  

Since I had put the C8 back on my Paramount for deep-sky imaging, it was out of focus, which would make landing on the planets more difficult and waste precious time.  So I picked up an moved the mount so that I could see the Moon and use it for focusing.  Then I moved it back over to the spot for the conjunction.

Finally, after peeling my eyes, Jupiter finally appeared a half hour after sunset.  Showtime!  I got the scope pointed at it and aligned, got them on the screen, and did some fine focusing.  I immediately started taking videos as soon as everything was ready -- I wasn't going to have much time before they sank below the fence line.  I also streamed the camera's view live on the Explore Alliance show for the conjunction.  

I had to move the mount back a few times to keep the planets in the scope's view -- one downside of such a large aperture is that even though the finderscope was still well above the fence, half the telescope aperture was below it, and the planets were dimming significantly.  After getting a good round of RGB exposures, I took a luminance exposure to get Jupiter's moons, and then removed the camera.  I had promised myself that I would look at them visually, and I am so glad I did!  I threw on the star diagonal and 25mm Plossl eyepiece, and the two planets looked awesome side-by-side. It was super cool to see them so close together.

The Result

I finally managed to get AutoStakkert to play ball by having it only worry about the planet that had the right exposure (since I had to take two different exposure times for their large difference in brightness), and I got the red, green, and blue channels stacked for both Jupiter and Saturn.  I used RegiStax to apply the wavelet deconvolution to sharpen them up, and then I used PixInsight's FFTRegistration script to align each set of RGB frames and combine them into color images.  Then I brought them over to Photoshop to manually composite the Jupiter, Saturn, and Jupiter's moons exposures into a single image, and did some color correction and adjustments.  The final result came out quite nicely, despite how low they were in the sky!

Date: 21 December 2020

UTC: 22 December 2020 02:30

Location: East Bay area backyard, CA

Object: Jupiter-Saturn Great Conjunction

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: ZWO 2-inch 7-position EFW, Astronomik CLS-CCD & RGB Type 2c 2-inch filters

Mount: Celestron NexStar SE

Frames: Best 20% of 250 each

FPS: 15

Exposure: R: Jupiter: 75ms, Saturn: 150ms

  G: Jupiter: 75ms, Saturn: 150ms

  B: Jupiter: 125ms, Saturn: 300ms

  Moons: CLS-CCD filter, 100ms

ISO/Gain: 139

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax 6, PixInsight 1.8.8-7, Photoshop CC 2021

You can only see three of Jupiter's Galilean moons because Ganymede was in transit (but with our current angle to Jupiter, there was no shadow until after Jupiter was too low to see).  

My prep work and practice paid off!  I'm very pleased with the image I got, and I even got to livestream it.  What a night!

Other Fun

Not only was December 21st the night of the Great Conjunction, it was also the night of the first-quarter Moon, and only an hour or two after the conjunction, the Lunar X and Lunar V would both be visible!  The last time I shot the Lunar X was accidentally when I took my very first videos of the Moon using my DSLR on the very same C8 back in May 2016, and I had never imaged the Lunar V.  So I took advantage of not having the focal reducer in place and took some nice Moon shots.  I did move the telescope back over to the Paramount though, since it was going to be a clear night and I wanted to squeeze in another night of deep-sky imaging.  The seeing wasn't great, but they came out all right.

Date: 21 December 2020

UTC: 22 December 2020 02:18

Location: East Bay area backyard, CA

Object: Moon

Attempt: 67

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: ZWO 2-inch 7-position EFW, Astronomik R Type 2c 2-inch filter

Mount: Paramount MyT

Frames: Best 20% of 1,000

FPS: 33

Exposure: 20 ms

ISO/Gain: 0

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax 6, Photoshop CC 2021

I even nabbed RGB videos of Mars before I put the focal reducer, off-axis guider, and focuser back on, although I haven't gotten around to processing it yet.

What a fun-filled night!

#510 - Saturday, April 17, 2021 - New Off-Axis Guide Cam!

Previous post: #403 - Sunday, October 11, 2020 - Planet-a-palooza!

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#403 - Sunday, October 11, 2020 - Planet-a-palooza!

 We haven't had a whole lot of clear nights here lately, so I have been trying to squeeze in some partial-nights of imaging when I can.  Unfortunately, the right ascension motor on my Celestron CGE Pro mount, the one I use for my science rig (for taking variable star and exoplanet transit data), has died.  So there will be a bit of a break in the science-data-taking while I get another rig set up.  After a talk I gave recently for the AAVSO 2020 webinar series, member Gary Walker, one of the leaders of the Instrumentation & Equipment section, offered to pass along to me a Celestron AVX mount as well as an older QSI 583 CCD camera.  I'm very excited to receive both!  The QSI camera should perform much better than the Orion Deep Space Monochrome Imager II I've been using on the science rig.  My Celestron AVX can't quite handle the 8" Newtonian I use on the science rig, but I think I got one that's on the lower end of their manufacturing tolerance -- I've seen people do better with their AVX's.  So I'm hoping perhaps his will perform better and I can use the Newt with it.  Regardless, it will be put to good use -- I've always got some kind of plan rolling around in my mind. :D

Meanwhile, the plethora of planets in the evening sky has been taunting me for weeks!  Normally I would set up my outreach rig and do some planetary imaging -- my 8" Celestron Schmidt-Cassegrain on my Celestron NexStar SE mount.  However, since I gave up on using my 11" SCT, I've been using the 8" all summer, and plan to keep it on my main imaging rig throughout the winter.  So I decided to spend a few evenings on the planets, and I swapped out my deep sky optics train for the planetary one.

For deep sky imaging, I use a 0.63x focal reducer/field flattener on the C8 to decrease the focal ratio from f/10 to f/6.3 (making the scope "faster") while widening the field of view.  The reducer puts me at an effective focal length of 1280mm, which gives me a large enough field of view to image most nebulae (except for the very largest ones), but not so large that I can't do galaxies and planetary nebulae.  However, for getting the best resolution on solar system objects, you want a looooooong focal length -- as much magnification as you can get away with given the aperture of your scope and the seeing conditions.  I previously used a Celestron 2x Barlow, but always got a bit of chromatic aberration from it, so I finally upgraded to a Baader Hyperion 2.25x earlier this year, and finally gave myself a chance to use it.  So I swapped out the focal reducer for the Barlow, and I also took off my PrimaLuce Esatto focuser because the last time I tried this, I had some trouble with it being too close to the scope and hitting the focuser knob.  

From the scope: SCT-thread to 2" adapter, 2" to 1.25" adapter, Baader Hyperion 2.25x Barlow, ZWO electronic filter wheel, ZWO ASI1600MM Pro

First up: Jupiter

After weeks of wildfire smoke, the air quality app on my phone reported an AQI (air quality index) of less than 10 -- a huge change from the 100-200 we've been having!  And on the few nights it hasn't been smoky, there's been clouds and haze.  But it was crystal clear, finally!  Now I just had to hope that the seeing was good.

The westernmost planet in the lineup is Jupiter, so I started there.  I got several videos on it using SharpCap and rotating through my red, green, and blue filters before it slipped behind my lemon tree, and the seeing was decent, and the image came out all right!  Bonus points: the Great Red Spot was prominently featured, and Europa was just to the side, about to pass behind the planet.

Date: 11 October 2020

UTC: 12 October 2020 02:14

Location: East Bay area backyard, CA

Object: Jupiter (and Europa)

Attempt: 26

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: Baader Hyperion 2.25x Barlow, ZWO 2-inch 7-position EFW, Astronomik RGB Type 2c 2-inch filters

Mount: Paramount MyT

Frames: Best 20% of 1-2,000

FPS: 13-16

Exposure: R: 60 ms

G: 60 ms

B: 75 ms

ISO/Gain: 200

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax 6, PixInsight 1.8.8-6

I am so happy that I took the time to swap out the focal reducer for the Barlow.  Having the extra magnification is making this awesome!  

One of 79 known Jovian moons, Europa was discovered in 1610 by Galileo and is one of the four moons easily visible with binoculars and small telescopes. It's a little smaller than our own Moon, but it has a water ice crust and thin oxygen atmosphere. Due to its very smooth surface, it is thought that a water ocean exists beneath the surface, which could harbor life. Future NASA missions are planned to explore that possibility.

We also have a nice view of the Great Read Spot here. The GRS is a massive storm that has existed for at least the past 360 years, when it was first observed. Within the cyclone, windspeeds can reach 268 miles per hour -- much higher than Earth's hurricanes. The storm is 1.3 times the diameter of the Earth!

Saturn

Saturn has got to be my favorite to observe visually.  In my C8, it comes in sharp and clear, and it really looks like someone is holding a picture up instead!  I've only come close to imaging it as well as I can see it visually once or twice.

Unfortunately, I spent too long on Jupiter, and Saturn didn't stick around long enough for me to get all three color channels on it, unfortunately.  However, I originally set the scope up for planetary imaging on Friday night, although I only got Saturn before clouds rolled in.  So here's the one from Friday:

Date: 9 October 2020

UTC: 10 October 2020 03:51

Location: Easy Bay area backyard, CA

Object: Saturn

Attempt: 27

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: Baader Hyperion 2.25x Barlow, ZWO 2-inch 7-position EFW, Astronomik RGB Type 2c 2-inch filters

Mount: Paramount MyT

Frames: R: Best 20% of 2,002 frames

G: Best 20% of 2,002 frames

B: Best 20% of 1,848 frames

FPS: 13

Exposure: R: 75 ms

  G: 75 ms

  B: 120 ms

ISO/Gain: 300

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax 6, PixInsight 1.8.8-6

I'm always happy when I get the Cassini division and some detail in the cloud bands.  And I love being able to see the shadow cast by the planet on the rings.  

Neptune

While I was waiting for Mars to peek out from behind my neighbor's garage, I went and nabbed a more difficult target: Neptune.  I've only imaged it a few times in the past, but it's a lot easier to get into my camera's crosshairs on the Paramount MyT than on my Celestron NexStar SE.  However, I need to make a better pointing model for the MyT; its slews are off by a decent bit, and I wound up having to sync on a nearby star to get Neptune in the image, which required me to go outside and actually look through my red-dot finder because the field-of-view was so small with the Barlow attached (only 13x10 arcsec).  But I finally did get it in my sights.

Date: 11 October 2020

UTC: 12 October 2020 06:22

Location: Easy Bay area backyard, CA

Object: Neptune

Attempt: 4

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: Baader Hyperion 2.25x Barlow, ZWO 2-inch 7-position EFW, Astronomik RGB Type 2c 2-inch filters

Mount: Paramount MyT

Frames: R: Best 20% of 100 frames

G: Best 20% of 100 frames

B: Best 20% of 100 frames

FPS: 

Exposure: R: 3.5s

  G: 3.5s

  B: 3.5s

ISO/Gain: 300

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax 6, PixInsight 1.8.8-6

No gas cloud details for me -- it's just too small!  At only 2.3 arcsec across, that's only 13 pixels wide at my pixel scale.  But still, it's a bluish-green disk, woot!  (Actually the camera didn't capture the color that well for this one -- I think it was too small to do the color calibration correctly.  So I took a guess based on what I've seen in the eyepiece.  It's not really right at all).

Mighty Mars

Mars reaches opposition in October 13th, which is why it is so big and bright in the sky!  Now is the best time to image it.  Luckily for us this year, it's reaching opposition at a time of the year and time of the night when the ecliptic is also quite high in the sky -- it culminates at nearly 58 degrees high for me right now!  Higher altitude = better atmosphere, since you're looking through less of it.

I spent a good chunk of time on Mars, and waited around for times of better seeing.  Of the 5 datasets I collected, #3 came out the best for me.

Date: 11 October 2020

UTC: 12 October 2020 05:22

Location: East Bay area backyard, CA

Object: Mars

Attempt: 19

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: Baader Hyperion 2.25x Barlow, ZWO 2-inch 7-position EFW, Astronomik RGB Type 2c 2-inch filters

Mount: Paramount MyT

Frames: R: 50 ms

G: 50 ms

B: 80 ms

FPS: 20

Exposure: R: Best 20% of 2,004

  G: Best 20% of 2,001

  B: Best 20% of 2,001

ISO/Gain: 139

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax, PixInsight 1.8.8-6

The reddish hue of Mars' surface is a result of the iron oxide that resides in the dust on the surface. Mars has a thin atmosphere, which you can see at the edges of the planet as we look through it edge-wise. It is believed to have had a much more substantial atmosphere, but since the planet lost its protective magnetosphere 4 billion years ago, the solar wind has been stripping it away. The pressure on the surface is about the same as being at 22 miles above the Earth's surface, and it contains only traces of oxygen. 

Visible at the bottom of the planet is the southern polar ice cap, which is a combination of carbon dioxide ice and water ice. The darker areas have less of the red dust, which is why they appear darker.

I managed to get a fair amount of detail -- not the most I've seen from other imagers, but still cool!  I'll need to keep an eye on the seeing forecasts and give it another go here in the near future.

And finally, Uranus

Wrapping up our solar system tour for the evening (very late evening) is Uranus.  By the time I finished Mars, I figured I'd take one dataset on Uranus, and then finally get to bed.  I've also only imaged Uranus twice.

Date: 11 October 2020

UTC: 12 October 2020 06:53

Location: Easy Bay area backyard, CA

Object: Uranus

Attempt: 3

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: Baader Hyperion 2.25x Barlow, ZWO 2-inch 7-position EFW, Astronomik RGB Type 2c 2-inch filters

Mount: Paramount MyT

Frames: R: Best 20% of 100 frames

G: Best 20% of 100 frames

B: Best 20% of 100 frames

FPS: 

Exposure: R: 1s

  G: 1.5s

  B: 1.5s

ISO/Gain: R: 300

      G, B: 250

Acquisition method: SharpCap Pro

Stacking program: AutoStakkert 3.0.14

Processing program: RegiStax 6, PixInsight 1.8.8-6

Similar story here -- it came out quite gray, so I fuddled with the colors.  But with both Uranus and Neptune, they're definitely disks, not stars!  You can see this visually at the eyepiece really well, which is super cool :D

Processing

I need to update my planetary processing tutorial with my new methods, but until I finally have time to do that, here's the rundown.

• Open the video for each filter in AutoStakkert; auto-place appropriately-sized APs, and then stack the best 20% of frames.  (I have RGB Align ticked so that it aligns the next video to the last.)
• Open the stacked images in RegiStax and adjust the wavelets.  I prefer to do that in Linear mode -- I've gotten much better results with it.
• Bring the wavelet-deconvolved images into PixInsight, convert to grayscale (RegiStax likes to save TIFs in RGB), and apply LinearFit to bring each color channel to about the same level (picking one of the filters as the reference).
• Combine the three color channels using ChannelCombination
• Correct the color using ColorCalibration, with the whole image used as white reference and a preview box of the background as the background reference.  (I have found this works very well for Mars, Jupiter, and Saturn.)
• Tweak saturation and the brightness curve with CurveTransformation
• Use MultiscaleLinearTransform to do a little more shaprening
• Use MultiscaleLinearTransform again to blur the 1-pixel level, since some weird pixelated hatching tends to result from RegiStax's wavelet deconvolution that looks like debayering when it's not
• Bring finished image into Photoshop to resize (I shoot my videos cropped to a small window size, usually 640x480, to speed up acquisition & processing and reduce file size).  I usually change the DPI from 72 to 300, and then drop the auto-upscaled size from 450% to like 200-300%, and then do some denoising in Camera Raw Filter as needed.  (This is mainly so that my watermark doesn't look super pixlated when the image gets blown up online).

Planetary processing is much quicker than deep sky.  I can crank through a dataset in about 10 minutes, including the documentation.  There are probably some more techniques I need to learn to get the most out of the wavelet deconvolution, though.

Planets are a fun diversion from deep-sky imaging, and they provide some quick satisfaction!

Next post: #457 - Monday, December 21, 2020 - Conjunction Junction

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

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#252 - Monday, November 11, 2019 - The Transit of Mercury

Occurring only 13 or 14 times per century, Mercury transits are relatively rare, but definitely catchable a few times in ones' lifetime.  I missed the more-rare transit of Venus in 2012, since it was a few years before I got into observational astronomy.  But I had marked my calendar well in advance of the Mercury transit!

Mercury and Venus transits occur more rarely than once per year because of the inclination, or tilt, of the planetary orbits.  Not only does Mercury need to cross between us and the sun (which happens far more often, given Mercury's 88-day orbit and Earth's 365-day orbit in the same direction), but both our own planet and Mercury need to be at the same orbital "level" when they do meet.

Credit: European Southern Observatory

Because of the orientation of the orbital planes, Mercury transits can only happen in May or November!  Crazy stuff.  Also, the transits are not evenly-spaced -- the last one took place in 2016 (I missed it because I had just started a new job, and couldn't exactly just be gone half a day so soon!), but the next one won't be until 2032.

Here in California, we didn't get to see the whole transit, since it started before sunrise in Pacific time -- we only got about half of it.  But they are quite long, and even from here, we saw it for about 4 hours.  But that was plenty -- really, Mercury is just a tiny black speck as it crosses the Sun's surface, not even visible with just solar eclipse glasses; you needed a telescope to see it.

Last night, I staged all my gear in the living room: 

- Celestron NexStar SE mount and tripod

- Celestron 8-inch Schmidt-Cassegrain

- ZWO ASI1600 MM Pro monochrome camera

- Home-built solar filter cell

- Eyepiece case

- Tool & spare parts box (you never know when you -- or someone else -- will need something!)

- Folding table

- Folding chair

- Celestron Power Tank battery

- Microsoft Surface 3 tablet

- Solar eclipse glasses (for use with the (non-magnifying) finerscope)

- USB and power cables

- Brand-new folding wagon I just got to haul all of it!

I brought the NexStar mount because, being an alt-az mount, it does not require polar alignment, and is thus much easier to set up during daylight.  I just have to point it at the Sun, say "hey mount, it's the sun," and it tracks it pretty decently.  I used the C8 telescope because of its long focal length.  I went with the monochrome camera because with Mercury being so small, I was going to need all the real resolution I could get, which is higher with monochrome cameras (and this monochrome camera also happens to have smaller pixels, by 0.5 micron, than my color camera).  

I got up at 4:30 AM, got ready, and got the car loaded.  I took off about 5:45 AM, but I had to stop for gas on my way out, since I forgot to do it yesterday.  Then I had to stop at another gas station because I forgot to grab water and snacks.  *sigh* I finally made it to the Pleasant Oaks Park in Pleasant Hill by 6:45.  The Mount Diablo Astronomical Society invited the Eastbay Astronomical Society (of which I am now a member) to view the transit with them from there.  It wouldn't really happen from the west side of the hills closer to the bay where we live, since of course the sun rises in the east, and the hills would block it! Sunrise was 6:45, but it wouldn't be cresting the hills on the other side of the town until after 7.  Everyone else was already there and set up, so I moved as quickly as possible!  Luckily, thanks to the new folding wagon and the roller case my astro-buddy John gave me that neatly fits my mount and telescope, I was able to get all my gear across the street and onto the baseball field in one trip.  The sky was brightening, but the sun hadn't shown up yet.

I was set up and ready to align on the sun as soon as it crested the hill.  It was a little chilly, but just fine with my lightweight jacket, fleece hat, and coffee mug.  We saw the sun break over the hill, and I was already almost right on top of it, and wow did it look incredible in the camera!  I also happened to be very close to focus, so I quickly started taking a video as the sun rose.  I'm so glad I did -- I got my favorite shot of the whole day right then!

Power lines, hilltop, and radio/TV tower, with the speck of Mercury just below the power lines.  Colorized in Photoshop.

I got the brightness settings adjusted, and let the video roll for about 2,000 frames.  Mercury was bigger than I thought it would be!  It was so exciting to see it.  Then I took another 1,000 frame video, aaaaaand my hard drive was full!  (The tablet has a little 128 GB solid-state hard drive).  Not to worry, I'd brought a USB 3.0 external hard drive just for the occasion.  Unfortunately, my USB hub couldn't power my power-hungry spinning external drive, so I gave up on that and used the new USB 3.0 flash drive I had just gotten,  Unfortunately again, even though it was advertised as 3.0, I was not getting 3.0 speeds.  Usually, monolithic files like videos copy the fastest, but this was still chugging along at something like 25 MB/s.  It wound up taking an hour to copy just those two videos over.  Eventually, I just unplugged the camera and plugged in my external hard drive directly to get it all off so I could start recording again.

During all of this, my tablet crashed three times as well.  The first time was a heat shut-down (just like what happened during the 2017 solar eclipse), so I used my eyepiece case to create some shade.  The second two were from my ZWO camera draining the battery on my tablet.  I had it plugged into the 5V, 1.5A USB port on my Celestron Power Tank, but the tablet really needs the full 2.4A it can take to not die while running the camera.  Luckily, my new-ish external cell phone battery than I got for playing Ingress, Pokemon Go, and Harry Potter Wizards Unite had a 2.4A port, so I ran it off of there instead.  Then it finally stayed alive.

While I was waiting for files to copy, I hopped around to a couple other telescopes to take a peek through some eyepieces.

Some members of the public showed up as well, which turned this already-fun event into an even-more fun outreach event!  I also had quite a few club members come by my rig to check out how I was doing the imaging.  Most people there were doing visual observing.  

At last, in the last 45 minutes or so of the transit, the videos finally finished copying to my hard drive (as well as a few more I had taken before detaching the camera), and I could take a couple more videos at the very end.

The white tape I added to the front of my solar filter really helped a lot to keep the heat down.  The first time I tested it out in my yard with black tape, the air between the filter and the objective had become quite hot, but this time everything stayed cool!  So that worked out nicely.

I had a difficult time processing the videos, since RegiStax balked at the large file sizes and AutoStakkert was giving me tons of weird artifacts, but I got a few processed.  I didn't do the rest because the seeing wasn't great, and there were some thin hazy clouds, so to be honest, the images are quite boring.  Which is why the radio tower image is my favorite!  I did grab a video of it leaving the Sun, so I'll probably turn that into a sped-up video at some point because it will look cool.  

What a neat event with fun people!  I had a great time.  And I didn't even have to miss class since it was Veteran's Day.  I wonder what kind of gear I will have and where I will be for the next one in 2032!

Next post: 2019 Advanced Imaging Conference

Previous post: #251 - Sunday, November 10, 2019 - California Dreamin'

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#201 - Saturday, August 3, 2019 - Final Members Night

With the movers coming on Monday to pack up my house for my move to California to start my PhD at UC Berkeley, I attended my last member's night with my astronomy club.  There was a pretty good turnout of about 20 people, along with a few who were camping on that nice weekend in trailers.  The forecast was iffy on the cloud situation, meaning that there would probably be some high-altitude scuzzy stuff.  Sounded like a perfect night to test out a new camera!

At least the clouds were pretty!

I didn't feel like bringing all of my gear, especially for an iffy forecast, so I planned on using one of the club's telescopes: an 8-inch Celestron Schmidt-Cassegrain on a Celestron CG-5 mount.  The new camera was one that my astro-friend John had very generously given to me recently: a ZWO ASI294MC Pro. It's the successor to my ASI1600MM Pro, but the color version. I had planned on buying the color version of my monochrome camera at some point for outreach events, transient phenomena (comets, Jupiter shadow transits, etc), and short nights, but now I have one much sooner! It would be a good night to test it anyway since I didn't have a way to mount my guidescope on the C8, so I'd just do short exposures until the cloud situation became unfavorable.

After some potluck dinner (theme: "Pies & Pints," for which I brought an apple pie), the thin crescent moon was setting in the west, and I grabbed some video on it before it dipped below the trees.  As I was prepping to move to Jupiter, someone spotted a weather balloon, and I just caught a glimpse of it in our 16-inch Dob!  But it had dropped its payload, separated, and deflated before I got my telescope over in its direction.  Darn, so close!  (And a perfect application for a one-shot color camera!)

I also enjoyed some yummy cake that some of my astro-friends got for me!

Having missed the weather balloon, but it not being quite dark yet, I imaged Jupiter and Saturn.  The atmosphere wasn't that great, however, so I'll have to see how those come out.

I didn't end up doing any deep sky imaging, but I did observe a dim M22 globular cluster, as well as M13, through the Dob.  I hung around until 11:15 PM, and then packed up and bid farewell to many of my astro-buddies.  It was a bittersweet goodbye, but we will be sure to stay in touch on social media.  I will miss them all dearly!

It has seriously been one heck of a ride so far.  After going it on my own for about 6 months after I got my first telescope in July 2015, a friend in the local astronomy club convinced me to check it out, so I went to a members night with him in February 2016, and joined the club shortly thereafter.  It was at that members night that my uncle messaged me asking if I would be interested in his Celestron computerized German equatorial mount and 11-inch Schmidt-Cassegrain, which really upped my game in astrophotography, especially once I figured out how to guide.  I also got to use a lot of astronomy club equipment, in addition to the awesome observatory facility we have (and really under-use!).  Many of my favorite images were taken on club equipment! Many club members gave me advice, tips, and even equipment, and even more gave me encouragement and friendship.  I cannot thank enough the many people in that club who have helped me along the way!

Clear skies, and I hope to catch you at the next star party!  (And don't worry, I've already found the astronomy club of the East Bay area!)

[ Update September 1, 2019 ] 

I said up above that I didn't do any deep sky imaging, but when I was working on my tablet yesterday, I found a folder of images of M20 Trifid Nebula that I had taken that night and forgot about!  I had to delete quite a few due to periodic tracking error and clouds, but I still managed to get a reasonable image out of the frames I did have.

Date: 3 August 2019

Object: M20 Trifid Nebula

Attempt: 7

Camera: ZWO ASI294MC Pro

Telescope: Celestron C8 (club's)

Accessories: N/A

Mount: Celestron CG-5 (club's)

Guide scope: N/A

Guide camera: N/A

Subframes: 34x20s (10m10s)

Gain/ISO: 139

Acquisition method: SequenceGenerator Pro

Stacking program: PixInsight 1.8.6

Post-Processing program: PixInsight 1.8.6

Darks: 0

Biases: 0

Flats: 0

Temperature: -20C

See on AstroBin

So when I went to process this, I ran into a problem pretty early on while trying to debayer.  The Bayer matrix pattern was not written into the FITS header, so PixInsight couldn't figure it out automatically.  The internet said it was RGGB, but when I tried that, I got a bright blue mess!

Now, I am pretty used to having weird color casts over images from one-shot color cameras, but they're usually green, and usually you can still see the object.  I thought that maybe RGGB was actually wrong then, so I tried every other option.  Some gave a green cast and looked almost normal, but when I zoomed in, I could see the pixel pattern, which told me it wasn't right.  Finally, I decided just to see what happened when I used RGGB and then ran PhotometricColorCalibration.  This yielded a correct-looking result after all.  I then discovered after doing some forum searching that sometimes you have to unlink the RGB channels in the auto-stretch process ScreenTransferFunction, and when I did that, then the colors appeared normal.  Very strange!  The rest of the processing went smoothly.

Since I don't have any calibration frames for this camera yet, and I didn't have a large number of exposures, the image turned out quite noisy.  I had to run MultiscaleLinearTransform twice and ACDNR once to get the noise down, but they did a pretty good job.

Here's the process:

- No darks/biases yet, so just stacking lights (short exposure anyway)

- SubframeSelector

- Scale: 0.47 arcsec/px

- Gain: 0.115 (not measured yet; borrowed value for unity on ASI1600MM Pro)

- Highest-scoring frame: frame45 (82.104)

- Debayered

- Registered with StarAlignment

- Stacked with ImageIntegration

- Combination: Average

- Normalization: Additive

- Pixel rejection: Linear fit clipping

- Had to unlink the RGB channels in ScreenTransferFunction to actually see the image properly

- Applied DynamicBackgroundExtraction

- Denoised with MultiscaleLinearTransform, with lum mask

- Corrected color with PhotometricColorCalibration

- Ran Deconvolution with a range_mask-star_mask, PSF from DynamicPSF, 20 iterations

- Stretched with MaskedStretch

- Further stretched and adjusted with CurvesTransformation

- More denoising with ACDNR

- Increased contrast with HDRMultiscaleTransform, 8 iterations

- Applied DarkStructureEnhance script

- More denoising with MultiscaleLinearTransform

I'm liking this camera!

Next post: #202 - Saturday, August 31, 2019 - New Digs!

Previous post: #200 - Friday, August 2, 2019 - Outdoor Outreach

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#200 - Friday, August 2, 2019 - Outdoor Outreach

For the last three years, I have averaged 50 nights of outreach per year.  I almost made the mark again in my fourth year -- hit my 200th astronomy night just two weeks after my fourth anniversary of amateur astronomy!  Still going strong :D  Of course, many clear nights at the Texas Star Party and in Chile helped.  We had a lot of clouds this past year in my Midwestern home location.

For my 200th astronomy night, I did an outreach event at a county park about a half hour from my house, where I've done a few other outreach events and talks.  The movers were coming on Monday to pack up my stuff for my move to California (I'm starting my PhD at UC Berkeley!), and they offered to come Friday, but I said come Monday and Tuesday instead! This let me still have the mount on my outreach telescope, my Celestron NexStar 8SE.  (My plan was to take the telescopes with me in my car, and let the movers take all my mounts).

I was really glad I had my outreach scope because there were a ton of people there!  It was largely an event for kids, and there were about 30 people or so there total.  We had two other astronomy club members present with telescopes as well, but we each still had lines to look through them.  Several other club members came out without telescopes to support.

First, I pointed my scope to the thin crescent moon that was sinking into the west, which was quite beautiful both with and without the telescope.  We got a little bit of earthshine on the darkened portion before it set.  I didn't have my DSLR, or else I would have grabbed some shots!  Next, I pointed it to Jupiter, which had the Great Red Spot for about twenty minutes before it slid around the  back of the planet, and then I moved over to the crowd-pleaser and personal favorite: Saturn.  It's always an absolute delight in my 8-inch, and despite some waviness from the primary mirror still cooling off, it did not disappoint!

At one point, a young girl (maybe about 9 or 10?) was over at my compatriot Phil's scope, and he was telling her about how the computer-driven mount worked.  She said she wanted to be an astronomer, which of course was very exciting.  When Phil gave a command for the scope to slew somewhere, her jaw positively dropped!  It was a lot of fun.  I let her control my scope later, and answered some questions about black holes and other space things.  I told her about the Event Horizon Telescope after I showed her the recent radio-wavelength image of the black hole at the center of galaxy M87, and about the incredible resolution of the effectively-Earth-sized telescope (achieved through advanced interferometric processing algorithms).  The resolution of this telescope collaboration would be equivalent to imaging an apple on the Moon, or reading a paper in New York from a cafe in Paris!

I missed the moment of maximum jaw droppage, but she was very impressed!

After the last few people left around 10:30 PM, I set up my ZWO ASI1600MM Pro with my electronic filter wheel onto my 8-inch, including the IR photometric filter I had recently added to the previously empty slot.  The seeing turned out better that night than expected, and I got some very nice results of Jupiter and Saturn!  I've only processed Saturn so far,  but I'll put up Jupiter when I get to it.

UTC: 3 August 2019, 03:51:09

Object: Saturn

Attempt: 20

Camera: ZWO ASI1600MM Pro

Telescope: Celestron C8

Accessories: Astronomik RGB Type 2c 2-inch filters, Schuler IR Johnson-Cousins photometric filter, 

Starlight Xpress filter wheel

Mount: Celestron NexStar SE

Frames: IR: 345/1000

R: 713/1001

G: 537/1000

B: 413/1000

Exposure: IR: 250 ms

R: 120 ms

G: 120 ms

B: 200 ms

ISO/Gain: 300

Stacking program: RegiStax 6

Processing program: PixInsight 1.8.6

It's quite small in the field-of-view of my camera, so this is cropped quite heavily, so I don't have great resolution (pixels) on it.  But when I eventually live somewhere where the seeing conditions are good enough to support using a Barlow or eyepiece projection, I definitely will do that!

I love outreach events!  They give me so much energy and joy :D

Next post: #201 - Saturday, August 3, 2019 - Final Members Night

Previous post: #199 - Tuesday, July 23, 2019 - New Scope!

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#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

See on AstroBin

😁😁😁😁😁😁😁😁😁😁😁😁

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

See on AstroBin

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.

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

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

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