Tag Archives: C2023A3

Post-Solar-Swing Comet C/2023 A3 Tsuchinshan ATLAS 

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Comet C/2023 Tsuchinshan ATLAS looped around the sun on September 27, 2024 and started on its path back towards the outer solar system.  For a few days, it was not visible because it was too close to the sun.  But it was predicted to become visible again around October 11, and it would be the closest to the Earth on October 12, 2024. 

We were in Dell City at the time and staked out a sunset viewing spot with a long view to the west. 

We made our first attempt to see the comet on October 10, 2024.  The comet should have been barely above the horizon at sunset, and unless it was truly extraordinary, we were unlikely to be able to see it.  We were treated to a lovely sunset, but we could not spot the comet.  I had told myself this was a dry run, so I wasn’t too disappointed.  And, when we returned back to our B&B, we were treated to a rare viewing of the northern lights from Texas.

We made a second attempt to see the comet on October 11, 2024.  The comet was supposed to be higher above the horizon at sunset than the day before.  There were low clouds in the sky.  We saw a lot of “fake comets” – bright airplane contrails.  Eventually my husband found the comet with his binoculars – success!  I started taking pictures, but I hadn’t used the right settings, and when I discovered that later, I suspected that the data would not be usable.  I was right – I can see a moving smudge in the images, but it’s not good enough for PixInsight to comet align the images (and there aren’t enough stars in the images for it to star align them).

We made a third attempt – third time is the charm! – on October 12, 2024.  The comet was supposed to be more than 10 degrees above the horizon at sunset, and it had been the closest it would be to the Earth, 0.47239 AU or 70668538.14 km, just nine hours earlier.  This time there weren’t any clouds.  And this time we could easily find the comet and see that it had a huge tail!  Given my experience the night before, I made sure I was using good camera settings, and I could see the comet and its tail in single images.

I used PixInsight to stack 50 images (8.3 minutes of data) to make this final image – my first post-solar-swing image of C2023 A3.  Isn’t it beautiful?

Today, on this day of Thanksgiving, I am most thankful for my family and friends, near and far.  But I’m also thankful for all the wonder to be found in this universe we live in, and particularly for this comet.  Happy Thanksgiving!

Camera geek info:

  • Canon EOS 60D in manual mode, 4 second exposures, ISO 800
  • Canon EF 85 mm f/1.8 lens at f/11 manual focus at infinity
  • Intervalometer
  • Tripod
  • Dell City, Texas Bortle 2-3 dark skies

Frames:

  • October 12, 2024 
    • 50 10 second lights 
    • 31 0.01 second flats
    • 31 0.01 second flat darks
    • 30 10 second darks

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXterminator
  • NormalizedScaleGradient

Comet Hunting Tailgate Party: C/2023 A3 Tsuchinshan ATLAS from Dell City, Texas

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Our last visit to Dell City, Texas ended with a fun event: going comet hunting with new friends. 

I knew from comet hunting with my husband the previous evening that C/2023 A3 Tsuchinshan-ATLAS would be visible in the early evening sky.  But this time, I wanted to image it over the Cornudas Mountains to the west of town.  I also wanted to have a view over the flat fields to the mountains and the sky above – which I could find by driving just a few blocks north of the center of town.

I invited some new local friends to join us, and they came in a pickup truck loaded with lawn chairs.  It was a comet tailgate party!

We had a great time visiting while we watched the sky as Venus appeared, followed by some bright stars, followed by the comet.  We could see it naked eye!  We could even see the comet’s tail naked eye!  It was pretty impressive.

It’s taken me over a month to learn how to and successfully process these pictures.  Each picture used one set of images for the comet, stars, sky, and foreground/mountains, but each part was processed separately.  The earlier pink picture where the comet is higher in the sky was made from 120 4 second shots (8 minutes of data).  The later orange picture where the comet is lower in the sky was made from 75 10 second shots (12.5 minutes of data).

One of the things I tried to do while processing was to make sure that all the fuzz around the comet and the anti-tail were real and not processing artifacts.  You can use the sliders below to compare the final images with the comet-only portion to see that, if anything, the final images show less fuzz than what was in the data.  (The comet-only data was calibrated, blur exterminated, star exterminated, comet-aligned, stacked, dynamic background extracted, and stretched.)

Comet C/2023 A3 4 second Comet Only and Final images
Comet C/2023 A3 10 second Comet Only and Final images

This event is high on my list of “coolest astro things I’ve seen.”  And I’m glad I had such a great group of folks to share it with.

What cool things have you shared with friends recently?

Camera geek info:

  • Canon EOS 60D in manual mode, 4 second and 10 second exposures, ISO 800
  • Canon EF 85 mm f/1.8 lens at f/8, manual focus at infinity
  • Intervalometer
  • Tripod
  • Dell City, Texas Bortle 2-3 dark skies

Frames:

  • October 13, 2024 
    • 120 4 second lights for pink image with higher comet
    • 75 10 second lights for orange image with lower comet
    • 30 0.01 second flats
    • 30 0.01 second flat darks
    • 30 4 second darks
    • 30 10 second darks

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXterminator
  • NormalizedScaleGradient

Comet C/2023 A3 Tsuchinshan ATLAS with M5

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Comet C/2023 A3 Tsuchinshan ATLAS put on quite a show after it rounded the sun and passed by the Earth on its way likely out of our solar system.  With an orbital eccentricity greater than 1, its orbit appears to be hyperbolic, meaning it’s not coming back unless something perturbs its orbit.

In this picture, you can see the comet’s bright nucleus and coma, its long dust tail, and its anti-tail, but not a separate ion tail.

When comets travel close to the sun, solar radiation heats up the comet nucleus, and it outgasses. Outgassing delivers both gas and dust to the region around the nucleus, forming a coma, a (temporary) atmosphere around the comet.  The solar radiation and solar wind act on this coma to push the gas and dust away from the sun to form a tail.  Three separate tails can be visible: the ion tail, the dust tail, and the anti-tail. The ion tail, also called the gas tail or type I tail, is the tail formed by the ionized gasses pushed away from the comet, and it points away from the sun.  The dust tail, also called the type II tail, is the tail formed by the dust pushed away from the comet, and it stays more in the comet’s orbit and appears to curve away from the gas tail.  The anti-tail consists of the larger dust particles that were not pushed as much and remained in the comet’s orbit.  The anti-tail appears to point towards the sun, and it is only visible when the Earth passes through the comet’s orbital plane near the time when the comet passed by the sun.  Because of these special conditions to see the anti-tail, it is not observed with most comets.

Another item visible in the image is M5, a globular cluster in our galaxy.  It is the large bright “star” to the right of the comet nucleus.  Because this image was taken with an 85 mm lens, and M5 was sorted to the “stars” image in my processing, it just appears to be a large bright star.  I suspect with some additional processing, I could have made it look fuzzier, though there aren’t a lot of pixels at this scale.  The Messier objects are “fuzzy” objects that comet-hunter Charles Messier made a list of because they weren’t comets – so it’s fun to see one next to a comet.  M5 is 24,500 light years away from Earth and has an angular size of 23 arc-minutes, making it about 165 light years across.  It’s thought to be one of our galaxy’s older globular clusters, at 13 billion years old.

Processing this image was tricky for several reasons: 1) it was made from images taken with a camera on a tripod, so the sky was moving in each frame, 2) the comet was moving relative to the sky, and 3) the images were taken at dusk, when the sky gradient is also changing in every image.  I benefited greatly from following the methods and advice in Adam Block’s Comet Academy.  One additional trick I used was to run BlurXterminator in correction only mode on all the registered images as my first step since the 4 second tripod images had visible star trails. 

Getting to this image has taken almost a month of watching videos, learning new tools, and trying various tool combinations and settings.  Some of these steps had to be run on each individual image – all 233 of them – meaning some processing steps took many hours.  After all that work, I am happy with the results.

I started with this image because I thought it would be the easiest of my set of C2023A3 comet images to process … the other images are from darker skies in terms of light pollution but closer to dusk and include a foreground.  But the comet was brighter!  I’m really looking forward to processing them and sharing the result!  Hopefully they won’t take a month each to process!

Camera geek info:

  • Canon EOS 60D in manual mode, 4 second exposures, ISO 1600
  • Canon EF 85 mm f/1.8 lens, manual focus at infinity
  • Intervalometer
  • Tripod
  • Pearland, Texas Bortle 7-8 dark skies

Frames:

  • October 15, 2024
    • 233 4 second lights
    • 30 0.0025 second flats
    • 30 0.0025 second darks

Processing geek info:

  • PixInsight
  • BlurXterminator
  • NoiseXterminator
  • StarXterminator
  • StarNet2
  • NormalizedScaleGradient

Comet vs Clouds: A Glimpse of Comet Tsuchinshan-ATLAS C/2023 A3

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On Sunday morning, we got up at 4:00 AM to drive to a spot with a long view to the East to go comet hunting.  I successfully got the telescope set up prior to the time when Comet Tsuchinshan-ATLAS C/2023 A3 was supposed to rise.  However, when the comet did rise, the ASIAIR could find stars, but couldn’t plate solve to figure out if it was pointing exactly right.  So I ended up starting imaging without having successfully scanned to the predicted comet location.  Since I could see a tiny comet in the first shot, I let the system take an automated sequence of shots.  60 second shots were too bright, so I started with 10 second shots, and when they became too bright, I switched to 1 second shots.

I also tried taking pictures with an 85 mm lens on my Canon EOS 60D, but that didn’t pick up the comet at all.  What it did pick up was the reason I didn’t get very many good comet images … clouds!  Of course, clouds are terrible for astrophotography, but they do lead to nice sunrise pictures.

We stayed for the sunrise, went out to breakfast, and then headed home.

Astrophotography is really two hobbies: capturing the images and processing them.

When we got home, I worked on processing the images I’d gotten.  I could see the comet in the 10 second images and in the 1 second images, but the 1 second image ones were generally partially through the clouds.  So I ended up using only the 10 second images.  Because there weren’t any stars captured in these short images, I only needed to process for the comet and use Comet Alignment to align the frames.

I’m hoping that I’ll get some better images later this fall.  Are you making plans to try to see this one?

Camera geek info:

  • Williams Optics Zenith Star 73 III APO telescope
  • Williams Optics Flat 73A
  • ZWO 2” Electronic Filter Wheel
  • Antila RGB filters
  • ZWO ASI183MM-Pro-Mono camera
  • ZWO ASiair Plus
  • iOptron CEM40
  • Bacliff, Texas Bortle 6 suburban skies

Frames:

  • 4 10 second red lights
  • 7 10 second green lights
  • 5 10 second blue lights
  • 30 0.02 second flats for green and blue
  • 30 0.05 second flats for red
  • 30 0.02 second flat darks for green and blue
  • 30 0.05 second flats darks for red
  • 1 second dark from library 

Processing geek info:

  • PixInsight
  • Generalized Hyperbolic Stretch
  • NoiseXterminator