ugly startrails in DSLR image

[drknoppi]

Hello, i found on my Canon 40 Da image with tripod after star alignement and after integration of 43 images  each 20 seconds
ugly star trails . With blink the movement direction is contrary to the normal rotation . ( no Darks, Flats,Bias, no Debayering)
Whats the problem ??

[astroedo]

Only an idea: you probably aligned on hot pixels that in short exposure could have more "signal" than stars.
Try to trim the noise parameters in star align.

But if you have RAW images you must debayer before aligning.

[Cosmick]

Hello, i found on my Canon 40 Da image with tripod after star alignement and after integration of 43 images  each 20 seconds
ugly star trails . With blink the movement direction is contrary to the normal rotation . ( no Darks, Flats,Bias, no Debayering)
Whats the problem ??

Looks like field rotation is overlaying the hot pixels into arcs on the aligned and stacked image.

[drknoppi]

Hello,
thanks for your ideas and hints,
but how can i fix this problem
Best regards Rainer

[Cosmick]

thanks for your ideas and hints,
but how can i fix this problem

Dark frames and/or Pixel Rejection during ImageIntegration.

[Andres.Pozo]

thanks for your ideas and hints,
but how can i fix this problem

Dark frames and/or Pixel Rejection during ImageIntegration.

If that doesn't work, you can use CosmeticCorrection to get rid of the hot pixels. It should be applied after calibration and before debayering.

[drknoppi]

Hello,
thanks looks much better with the defaults of Pixel rejection, special parameters to use  ?,  method ?
Best regards Rainer

[Cosmick]

thanks looks much better with the defaults of Pixel rejection, special parameters to use  ?,  method ?

The answer is almost always - it depends. 
If you hover your cursor over most tools in Pixinsight, up will pop the 'Tool Tips'. These will often supply the information you need to make an 'informed' choice about which options to try.

[drknoppi]

Hello all,
so i will do it thank you very much
Rainer

[drknoppi]

Hello again,
is not perfekt, but  better  , 44 x 20 seconds Cassiopeia widefiled Canon 40 Da with 800 ASA with simple tripod,
the main problem was the pixel rejection in imageintegration, thanks all for the good ideas.
Rainer 
b.t.w.
In the Future will follow a new image of cassiopeia if i understand TVGDenoise better