CometAlignment - SubtractImage bug ?

[Walcho]

Hi everybody,

I made some pictures of the comet 21p Giacobini Zinner.
I used the "CometAlignment" process and made an integration in LinearFit to eliminate the stars and get a comet without stars.

To get an a star field without comet, I use again the "CometAlignment" process with the "Subtract Image" function, in order to subtract my comet intergration from each target image.

Unfortunately, in the final images the comet is still visible, no operation has been performed.

Can you confirm that it is a bug?
Is there another way to proceed? Pixelmath?

Thanks in advance for your support.

[astroedo]

Hi, I successfully subtracted the comet image.
Try to DISABLE normalization and Weighting in ImageIntegration when you perform the integration of the "starless" comet.

Then activate "Normalize" and deactivate Linearfit in CometAlignement when you perform the subtraction.

I've published a Video tutorial on this, unfortunatey it's only in Italian, but I hope that you can follow the video.

https://www.youtube.com/watch?v=RmgjvC8c_yc

[Walcho]

Hello Edoardo,

Thank you for your answer, meanwhile I proceeded another way but I will have a look at your tutorial. I do not speak Italian, although I love this language, but it will not be the first tutorial in Italian that I look at.