Images that won't get registered by APP (any version)

My question was serious. Is there a way or could there be an additional mode for images with a small amount of big stars?

Walter (@walsc)

I think APP probably can register this sort of image, but may require some parameters to be tweaked. You may have already tried all of these suggestions, in which case - no harm done.

In 3) Analyse Stars you will want to minimise the chance that APP will misidentify noise or other defects as stars. Turn on the cosmic ray reducer and possibly a slight increase to the lower limit area size. Also I think you should decrease the automatic stars target significantly. I would start with 100, if that doesn't work maybe try 50, maybe even lower.

In 4) Register I would force the simplest pattern recognition system by choosing triangles. Probably unnecessary but play it safe.

If none of this works I do have one other idea, but its a last resort, act of desperation sort of thing. You could try registering and saving the frames using DeepSkyStacker. When I was first starting in astrophotography I (unwisely) started with a Schmidt-Cassegrain telescope and used DSS for stacking. It managed to register some truly terrible images that I captured. I suspect that DSS has moved on from the early version I was using, but if you can use it to register and save your frames, then they could be brought back to APP (with registration disabled) so you can use the other APP goodies.

JC

@connor231 Thank you, I will try your suggestions. I also had this idea with DSS, but DSS does not support FITS. I now played around with Astroart 9, this is more likely designed for astronomers, not very comfortable to use, but I managed to get useful results out of it.

I tried again with APP, nothing seems to work. I even tried comet-registration. 

I may be misremembering it, but I'm reasonably sure I used to load fits files to DSS.

JC

You're right, I got something mixed up. DSS can of course handle FITS files.
I tried it yesterday with DSS, and the result surprised me extremely positively. Not only does it work with these images, but the results are really very clean and high-quality.

Glad you got a good result.

JC

Hi Walter @walsc,

Thank you very much for sharing this issue.

Yesterday, I release APP 2.0.0-beta45 with many fixes and improvements for 4) Register, so please try your data in the new version and let me know the results.

I see from the image that indeed it would be a challenge with so little stars. Like John indicates, it should help to turn on noise reduction in 3) analyse stars.

In 4) Register, the comet-one star mode should be tried as a last resort. But I read already that it didn't seem to work?

Can you upload this data so I can work and test with it? I have several data sets with little stars and long focal lengths and they all work now, your data apparently is even more difficult. Maybe the stars are so little that even triangle descriptors are not an option and I need to implement a different way to make that work.

https://upload.astropixelprocessor.com/

username: uploadData

password: uploadTestData

Please make a folder with your name and issue like : Walter-littleStars-issue

and let me know once uploaded.

Thanks,

Mabula

Hi Mabula, thank you for your support. Upload is pending, I have tried now Beta 45 with default settings, it registers significantly more frames, but by far not all. Will try to tweak the parameters.
Edit: upload done.

Thanks Walter @walsc, great that beta45 already is showing improvement on this issue as well. I will test the data that you uploaded. Thanks a lot !

Mabula