M81/M82 with IFN and a comet

Hello everyone.
Today I present my last picture of the sky. This is a combination of 4h in RGB ans 2h in Ha.
The pic depicts the galaxy couple M81/M82 within the IFN and a comet at the right bottom of the image.

Not easy to process, but I’m happy of the result. Even if chrominance noise is maybe too high.

Canon EOS 100D + Samyang 135mm
iOptron SkyTracker
4h de pose en RGB
2h de pose en Ha
Siril, GIMP, Darktable


Gorgeous image! (and I can see the frame for the weekend encounter)

I was trying something similar… well without the IFN stuff. Without the Halpha. With a shorter exposure. And without the wild field :smiley: :smiley:

45m min ISO1600 on Nikon 7000D with a 300mm f/5.6 lens. Only SiriL processing and I’m not yet happy with the color result (Photometric balance, but with a lot of light pollution form the city)

At 300mm the 45min results on a very trailed comet, so, I suspect that you have processed the comet independently and put it again in the picture. Isn’t it?


Thank you :).

In fact, Ha stuff does not bring a lot of information in this area… I was disappointed.

No. I was at 135mm. This comet is quite slow and the rejection algorithm did the job. So the trail is not very important. To be honest, I wasn’t aware the comet will be here, I did see it at the processing stage.

I love to see the IFN! Thanks for sharing it!

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Very nice! 4h really helps. I am getting IFN at f/6.3 with 1h and ISO1600, but it’s scarcely above noise level. I am sending my Star Adventurer back to the factory for repair/replacement. The 1 min time limit at 100mm is awful compared to other units of the same model.

Well, all depends on the focal length :slight_smile:. Yesterday was the closest approach and with a focal length of 600mm, 1h of exposure was too much for the comet

Any clue on how to process this frame?. I’ve tried to align on comet and the use this frame to subtract the comet from each frame, but SiliL doesn’t have the required tools. With PS I was unable to obtain better results.

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For my comet images I generally use a combination of GIMP and Siril (comet and star registration).

yes, I understand. But I was trying to using the comet registration image to remove the comet from the star registration individual frames. I assume that you simply extract the stars and remove all the blurred comet before reinserting the stacked one. Isn’t it?. One remaining issue is the color balance on the comet registration image I can’t use the photometric one

You can’t totally remove the comet. It is difficult. But you can remove stars by using high rejection.
Then you put the comet on the blurred one (by trying to removing the blurred with clone stamps for example).
Here an example I’ve done, some years ago.

About the color, this is not an issue as photometric color calibration is not the only tool available.

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