Unknown (to me) object in M44

9 replies349 views
Alex Penzias avatar

Hello there!

since I have quite a few reflections in my mono imaging train, I have optimised everything over the past few weeks, i.e. dissassembling the optical train, painting internal shiny stuff black, increasing the dithering amount, repositioning the OAG prism, and optimizing flats. Yesterday I tested my setup on M44 and took 60×60s L and 20×60s RGB images. After having finished post processing and checked if any reflections were still visible, I found this weird colored streak in my image. After blinking through the raw data I saw a small object which looked like a faint star and which moved from right to left in the image. The weird coloring makes sense now since I shot in the order of LRGB with my filter, therefore the streak starts out in grey from the right and then goes through RGB in the same order to the left. The length of the colors of the streak also corresponds to the imaging time with each filter.

📷 M44_uo.pngM44_uo.pngOut of curiosity I would like to see if I can identify this object, but as I have never done something like this I don’t know on which website/database to look. I’d assume it’s not a satellite, but what could it be? I’ve only checked Stellarium so far and during the imaging time I did not see any object passing through this region. Could anyone be so kind as to point me in a direction or tell me what this object could be?

Thanks and clear skies!

Alex

Well written Helpful Respectful Concise Engaging
Quinn Groessl avatar

It’s some sort of artifact. Usually it repeats as it does in your image. In the extreme bottom left it’s a bit less prominent, but it’s there as well. I don’t know what causes it, but I see it in images occasionally.

Alex Penzias avatar

Hi Quinn,

thanks for your reply! Is it really an artifact? When I blink through the raw data, I see a small round object moving from right to left. Since it is a small dot moving from right to left this would also explain it looking like a streak in the stacked image above.

I did not notice a similar streak on the lower left at the edge of the image as well. Just checked it in Blink and this, too, is a very faint dot that moves from right to left.

Clear skies,

Alex

Well written Respectful Concise Engaging Supportive
Tony Gondola avatar

It’s probably an asteroid. If you get a copy of SAS pro (it’s free) you can use the “supernova and asteroid hunter” script along with your data to find out which one it is:

https://www.youtube.com/watch?v=cgq8J6wsEOs&t=1s

Well written Helpful Concise Engaging Supportive
Alex Penzias avatar

Thank you @Tony Gondola for the help. I shall try and use the script from Setiastro.

Clear Skies,

Alex

Respectful
Brian Puhl avatar

100% an asteroid, this is what they look like with mono imaging.

You can plate solve with asteroids in your image in pixinsight, or plug in your date/time/location into stellarium after downloading asteroids via plug in.

Helpful Engaging Supportive
Beverly Bambury avatar

I am really glad you posted this because I had no idea what to look for in this case. Really appreciate the comments. Thank you!

Respectful Supportive
Armin Lukas avatar

Something similar happened to me as well:

https://www.astrobin.com/pnhrnw/

With pixinsight I found out it was the Psyche asteroid

Jan Erik Vallestad avatar

As already pointed out those R/G/B streaks are always very telling, and they are moving objects. I had a really prominent one in one of my images this season that turned out to be a minor planet casually orbiting through the FOV. I did a write up as to how I went by to identify the object here: https://app.astrobin.com/u/JanvalFoto

MPChecker might be a good place to start. Happy hunting!

Helpful Concise Engaging Supportive
Alex Penzias avatar

Thank you all for your tips, insights, and confirmation! I will see if I can make something out of this once I am done with my current actual project, but this was something I had not yet seen before since I have just started mono imaging.

Thanks Jan for the link! I will make myself familiar with this site 🙂! And you are most welcome Beverly! Since I wasn’t sure how to properly describe this in my image, I thought a picture might say more 😉. In case you have this issue as well, now you know!

Clear Skies to all of you and thank you again!

Well written Respectful Supportive
Related discussions
First image with new Edge 9.25 scope reveals possible discovery.... Can i get peoples opinions please
Hi guys, i’ve just processed my first image using my new edge 9.25 hd scope. Given that it is not a very eye catching image i don’t think many people are going to view it, but i would really like some input/opinions on my possible discovery. It is no...
Troubleshooting optical issues with new scope setup and image quality.
Jan 14, 2026
Star shape issues after putting in main mirror mask
Astrobiners, I have a CarbonStar200 to which I added a primary mirror mask. Having added the mask, my star shapes aren’t what I would expect and I’m soliciting thoughts on possible root causes. Attached are two images - these are staged and simply sc...
Star shape problems may relate to optical train artifacts and reflections.
Dec 27, 2025