APOD: The Unusual Tails of Comet... (2024 Nov 11)

[APOD Robot]

The Unusual Tails of Comet Tsuchinshan-Atlas

Explanation: What created an unusual dark streak in Comet Tsuchinshan-Atlas's tail? Some images of the bright comet during mid-October not only caught its impressively long tail and its thin anti-tail, but a rather unexpected feature: a dark streak in the long tail. The reason for the dark streak is currently unclear and a topic of some debate. Possible reasons include a plume of dark dust, different parts of the bright tail being unusually superposed, and a shadow of a dense part of the coma on smaller dust particles. The streak is visible in the featured <a hrf="https://www.instagram.com/p/DBJr0r3v4WI/" >image</a> taken on October 14 from Texas, USA. To help future analyses, if you have taken a good image of the comet that clearly shows this dark streak, please send it in to APOD. Comet Tsuchinshan–ATLAS has now faded considerably and is returning to the outer Solar System.

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[Christoph Gerber]

I simply thought that the dark streak was the projection of (the continuation of) the anti-tail against the tail, since the anti-tail lies between the tail and the observer. And near the (very) bright head of the comet it is almost missing because of the forward scattering of the anti-tail dust. Isn't it?

best regards, Christoph

[JohnD]

I agreed with Christoph, until I thought that this explanation depends on two things.
That the majority of the luminosity of the dust tail is reflected sunlight
And that anti-tails appear when the Earth passes through the orbital plane of the comet.

So wouldn't a dark streak/shadow on the dust tail appear whenever an anti-tail was visible?
How common is it for the Earth to pass through a comet's orbital plane?

John

[Astronymus]

Couldn't even see it because the skies were cloudy all the time.

[JohnD]

You will have had the same weather system as us, Astronymus! "Anticyclonic Gloom"!
Some parts of the UK have seen the Sun for less than an hour in the last month!

John

[kybik0606@gmail.com]

C/2023 A3 Tsuchinshan-Atlas
Copyright: Chernik Aliaksey

c2023_GraXpert.jpg

[kybik0606]

C/2023 A3 Tsuchinshan-Atlas with black streak
Instagram: Chernik Astronomer
Copyright: Chernik Aliaksey

Technical parameters of the photo:
Place - Zhodino, Belarus, 54N 28E
Date - 10/18/2024
Telescope - Sky-Watcher 130PDS
Astrocamera - ZWO 585 MC
Focal length - 650 mm
Integration time - 48.5 minutes (97 frames * 30 seconds)
Gain - 252
Image processing method:
1. Calibration of light frames using 20 darks and 30 biases
2. Removing stars from calibrated frames
3. Stacking calibrated frames separately with comet and stars in Siril
4. Alignment of the comet and the stars according to its original position in SIril
5. Background alignment in GraXpert
6. Photometric color correction in Siril
7. Histogram stretching

[JohnD]

Above taken a week earlier than the APoD. Earth not in plane?

[kybik0606]

As far as I know, APoD was received on October 14, a difference of 4 days. Sorry, I didn't understand your question.

[evankrall]

I took a sequence of images of Comet Tsuchinshan–ATLAS on the evening of Oct 17 from San Francisco, and after stacking them, the dark streak in the tail is fairly apparent.

Operations done in Siril to produce this composite image:

• Alignment, first with auto-alignment (which aligns the stars) then with Siril's comet/asteroid alignment mode.
• mean stacking without rejection, additive+scaling normalized input, unnormalized output, no image weighting, unequalized RGB
• Crop (x=70, y=83, w=1873, h=2376)
• Background extraction (Correction: Subtraction)
• Histogram Transf. (mid=0.004, lo=0.024, hi=1.000)
• Background neutralization
• Color Calibration

The subs were captured over about 40 minutes, with around 29 minutes of total integration time.

I also produced a video out of the same frames: https://www.dropbox.com/scl/fi/evb6sr67 ... mlwoa&dl=0 -- note that the Dropbox preview is heavily compressed so most of the detail gets lost into blocky noise. If you click the download link, you should get the original video (should be 407MB), which is much better.

For the video, I applied many of the same operations as above on the input frames, converted them to JPEG, and then produced a video from them with ffmpeg. I applied a moving average of a few frames to reduce the noise somewhat (the raw frames are quite noisy after background subtraction!)

[nlefaudeux]

the dark streak is a feature shared among a lot of great comets that are sufficiently dusty.

comet NEOWISE on July 7th 2020: (see the zoomed inset)
https://hdr-astrophotography.com/wp-con ... site-1.jpg

comet HaleBopp
http://www.bellatrixobservatory.org/hb271ls.jpg

Comet Donati


Comet Coggia

[mcrana]

C/2023 A3 on Oct 21, 2024
https://drive.google.com/file/d/10FjOEh ... sp=sharing

And on Oct 24, 2024
https://drive.google.com/file/d/1FbYg4t ... sp=sharing

[pavelc]

Here is my image of the C/2023 A3 captured on October 24th, 2024 with 30cm f/4 telescope. I believe a hint of the black streak in the tail is visible, but also the anti-tail is more blurred, compared to the APOD image.

Total exposure time 36 min, stack of 24 30 sec exposures of each R, G, and B channels

---

Full resolution image is here https://www.tcmt.org/download/C_2023_A3-TCMT.png

[OmerBaram]

APOD submission "C/2023 A3 (Tsuchinshan–ATLAS)" by Omer Baram

Discovered in early January 2023 by two observatories (one in South Africa and one in China), the comet has been closely monitored since. It originated in the Oort Cloud, a vast region of icy and rocky bodies surrounding our solar system.

I photographed the comet on October 21th from the Negev desert in southern Israel, the comet was approximately 4.55 in magnitude and in a distance of 0.66 AU from earth

For full resolution, visit:
https://astrob.in/full/yg179t/B/?real=

Full details:
Camera: ZWO ASI071MC Pro
Mount: Sky-watcher NEQ6 Pro belt mod
Telescope: TS Optics 80mm F/7
Filter: Optolong L-pro
Guide Scope: Svbony 60mm
Guide Camera: ZWO ASI120MC-S
Date: 21.10.24
Location: Negev Desert
Exposures: 60sX70

[johnnydeep]

To all those people posting their excellent photos of the comet and its dark streak, are you also sending them to APOD as requested in the text? Regardless though, they're nice to see here as well!

[OmerBaram]

To all those people posting their excellent photos of the comet and its dark streak, are you also sending them to APOD as requested in the text? Regardless though, they're nice to see here as well!

Yeah! I just sent mine today and Nemiroff replied and asked me to upload it to this topic as well

[morvek]

Attached is an image of the comet taken on October 14th from my home in southeast Arizona. The 60 second subframes were captured between 18:42 and 19:17 MST. The subframes were stacked using the comet alignment process in PixInsight. Below is a list of the equipment I used to capture the subframes:

Telescope: Sky-Watcher 100ED Esprit APO Triplet
Camera: ZWO ASI2600MC Pro
FOV: 2.4 by 1.6 degrees.

I originally posted the image to APOD. Robert Nemiroff asked me to post the image here.

Mark

[fun2mas@gmail.com]

I am sending images of the comet that were taken on 13/10/2024 using a ZWO ASI 533MM PRO camera and a Borg ED77 telescope with a 0.8x reducer. They capture a dark streak leading from the comet's nucleus. Images have been edited to increase contrast and band visibility.

55x1s


71x2s

Tomáš

[toniscarmato]

In that image you can see the dark line on two different days. I am analizing those structures in the inner coma to study the evolution.
Also, are visible the dust waves around the false nucleus.

Comet C/2023 A3 inner coma structures on 2024 October 13th and 14th.
Toni Scarmato's Observatory, San Costantino di Briatico, Calabria, Italy
MPC Code L92
Telescope 25-cm Newton f/4.8+CMOS ASI294MC PRO

Regards,
Toni Scarmato

[Tim Hunter]

Here are links for two images showing the dark streak in Comet Tsuchinshan-Atlas. They were taken on the night of October 14, 2024, at the Grasslands Observatory in Southeastern Arizona with a PlaneWave CDK24 24-inch f/6.5 telescope and a Finger Lakes Instrumentation Proline KAF9000 CCD. The color image is a combination of single 30-second exposures in Cousins-Johnson R, V, and B combined with a 30-second luminous exposure. The black and white image is the luminous 30-second exposure processed to show the dark streak.

Tim Hunter
Black and White Image: https://www.3towers.com/LatestNews.html#
Color Image: https://www.3towers.com/Grasslands_Cont ... Page2.html#

[Tim Huinter]

Here are the correct links for the images on my last post.

Tim Hunter


https://www.3towers.com/Grasslands_Imag ... etails.jpg

https://www.3towers.com/Grasslands_Imag ... c_LRGB.jpg

[FDolphin]

Hello APOD and fellow astronomy enthusiasts,

I'm excited to share an image I captured of Comet Tsuchinshan–ATLAS, where a double streak is visible in the comet’s tail. This stack was created from exposures taken on the night of October 23, 2024, between 20:01 and 21:56 local time, from Salles Courbatiès (GPS coordinates: 44.6° N, 2.0° E).

My article on website : https://planetediy.fr/comete-c-2023-a3- ... han-atlas/


Youtube video of the night:

Click to play embedded YouTube video.

https://planetediy.fr/wp-content/upload ... _Calib.jpg

Equipment Used
Telescope : TS-ONTC HYPERGRAPH 10″ (254/1000, F/D 4)
Reducer Corrector : 0.85×3″ , giving an effective focal length of 863mm (F/D 3.4)
Mount : EQ8R-Pro on DIY steel pillar
Camera : ZWO ASI2600MC DUO
Filters :
Optolong Clear 2″
Focusing : ZWO EAF (Electronic Automatic Focuser)
Filter wheel : ZWO EFW (5 positions, 2″)
Shooting Data
Total integration time : 1 hour and 37 minutes
Clear : 194 exposures of 30 seconds, Gain = 100 (-15°C)
Data Processing
Software :
PixInsight
NINA

While I also captured images on October 21 and October 29, these are still in the processing phase, and I hope to share them soon if they reveal additional details.

Thank you for this opportunity to contribute. I look forward to any insights and discussions that might arise from this observation!

Clear skies,

[johnnydeep]

Hello APOD and fellow astronomy enthusiasts,

I'm excited to share an image I captured of Comet Tsuchinshan–ATLAS, where a double streak is visible in the comet’s tail. This stack was created from exposures taken on the night of October 23, 2024, between 20:01 and 21:56 local time, from Salles Courbatiès (GPS coordinates: 44.6° N, 2.0° E).

My article on website : https://planetediy.fr/comete-c-2023-a3- ... han-atlas/


Youtube video of the night:

Click to play embedded YouTube video.

https://planetediy.fr/wp-content/upload ... _Calib.jpg

Equipment Used
Telescope : TS-ONTC HYPERGRAPH 10″ (254/1000, F/D 4)
Reducer Corrector : 0.85×3″ , giving an effective focal length of 863mm (F/D 3.4)
Mount : EQ8R-Pro on DIY steel pillar
Camera : ZWO ASI2600MC DUO
Filters :
Optolong Clear 2″
Focusing : ZWO EAF (Electronic Automatic Focuser)
Filter wheel : ZWO EFW (5 positions, 2″)
Shooting Data
Total integration time : 1 hour and 37 minutes
Clear : 194 exposures of 30 seconds, Gain = 100 (-15°C)
Data Processing
Software :
PixInsight
NINA

While I also captured images on October 21 and October 29, these are still in the processing phase, and I hope to share them soon if they reveal additional details.

Thank you for this opportunity to contribute. I look forward to any insights and discussions that might arise from this observation!

Clear skies,

Very nice image!

[Astronymus]

You will have had the same weather system as us, Astronymus! "Anticyclonic Gloom"!
Some parts of the UK have seen the Sun for less than an hour in the last month!

John

Not that. Here the mountains are the problem.
1. You don't have a horizon at the bottom of the valleys for obvious reasons.
2. The mountains either accumulate clouds or produce them depending on the wind direction. Most of the time it was föhn weather. That means stationary clouds on the leeside of the mountains. I miss living in the flatlands.