Problem with ImageRegistartion.

[gianpri]

I have a big I have a big problem with ImageRegistartion. I used BatchPreProcessing and this is the result:
Despite StarAlignment: 20 succeeded, 0 failed, 0 Skipped, the stars are not aligned. I also tried with ImageRegistration but I got the same result. is the first time that happens to me. I enclose a single image. The same problem also occurs with another shot of the same evening Eskimo nebula (see individual photo). I tried to draw pictures taken previously and everything works fine. Why is this happening? Thanks
Giovanni

[Alejandro Tombolini]

Hi Giovanni,

I would first check the _c (calibrated images) from BPP and see if they were correctly calibrated. Check if hot pixels were removed from the individual frames. 

Saludos, Alejandro.

[msmythers]

Giovanni,

It looks like the images are being registered to Hot Pixels. I would check the images generated before registration but after calibration for Hot Pixels. You might need to retake Darks. You might also need to use Cosmetic Correction. The BatchPreProcessing script is limited in parameters adjustments. In the StarAlignment tool you might be able tweak the parameters in the Star Detection and Star Matching sections to overcome the issue.


Mike

[gianpri]

Thanks, Mike and Alejandro. The individual images attached are after calibration but before alignment. I believe that not all the hot pixels have been removed. I took the dark as I always have ever had without ever recording problems. I also tried to change the parameters of detection of the stars in StarAlignment unsuccessfully. Try CosmeticCorrection before alignment. I hope to solve.
Giovanni

[TobiasLindemann]

Hi Giovanni,

I have sometimes the same problem, when working with high focal lengthes and as a result big stars. In StarAlignment you can choose "detected stars" as a working mode. So it is easy to check what is detected as a star (real stars, or hot pixels). Try to increase the "detection scales" and "hot pixel removal". After debayering the hot pixels are a little bit blurred and not longer one pixel in size.

Tobias

[gianpri]

Hello Tobias. I tried "detected stars" and also by varying the values of "detection scales" and "hot pixel removal" are recognized both the stars that the hot pixels. I think the only solution is to use CosmeticCorrection to remove the hot pixels. Thanks for the reply

[gianpri]

I finally solved: I deleted the pixels hot / cold with CosmeticCorrection; StarAlignment now works perfectly.
Thanks for the help.

Giovanni

[msmythers]

Giovanni

Great to hear you found a solution.


Mike