star alignement

[wbernhardt]

When trying to align my debayered images the program comes back with registered successful, but the images are not in-line. I used frames with NGC 3718 and a C11, so the stars are "bigger" than with a refractor, and there are only some dozens stars, but I have tried several things, ie changed almost all parameters (one at a time, before making combinations), and it also faisl when using the batch preprocessing program.
What can I do? (BTW: everything works fine with DSS).
Many thanks in advance,
Wolfgang

[pfile]

could be that SA has found hot pixels instead of stars. did you try increasing the Noise Scales in the Star Detection portion of StarAlignment?

rob

[TobiasLindemann]

Wolfgang,
with long focal lengths I had the same problem. What helped is, to increase the detection scales, or what Rob said "increase the noise scales". If you really have much hotpixels, the "Cosmetic Correction" before debayering would help too. If you still have problems, please post two images, if you can upload it anywhere (Raws preferred).   

Tobias

[wbernhardt]

Dear both,
thank you very much, this was it!! I increased noise scales from 1 to 3 and hot pixel removal from 1 to 2 and it worked perfectly!
Best regards,
Wolfgang

[pfile]

excellent - SA has a mode called "detected stars" which will simply generate an image showing where it thinks the stars are. if you generate one of these and zoom in it will be obvious that it has latched on to hot pixels.

rob

[TobiasLindemann]

Rob,
wow, I had not looked at the modes before, thanks   

Tobias