DSS Comet stacking help please

[thomasv]

Trying to stack some 46P captures in DSS, but it doesn't come out correct. 

I first register all light frames (I have no calibration frames), then going through each sub and manually marking the comet nucleus with the comet tool, then do a Kappa-Sigma stack. The comet still appears stretched in the stacked image while the stars are aligned. I've attached a crop of the first and last sub, the resulting stacked image, and a screengrab of dss.

Any suggestions appreciated, I haven't tried changing the parameters of the stacking, and subs are pretty wide-field, could that be an issue?

 

[emadmoussa]

Very nice!

[Pete Presland]

I have never seen that effect before, its odd the stars are not streaks as well, considering you are stacking on the comet only. Also not sure what the "green noise" is in the screen grab either.

[thomasv]

The green circles are stars marked after registration, don't know if it's normal. I should have said I'm using DSS 4.1.1 64bit version.

 

[Pete Presland]

I don't know whether its relevant or not, but when you register the images how many stars are selected? 

[thomasv]

Between around 20000-23000.

[happy-kat]

You should ensure one frame where the score is highest as your reference frame, right click on it.

I've found this time around best results are stack on both stars and comet.

[Pete Presland]

21 hours ago, thomasv said:

Between around 20000-23000.

That seems a huge amount of stars, not sure whether its relevant or not.

 

 

[thomasv]

Thanks, still no luck though, reduced the number of stars to about 1800 by moving the star detection treshold slider and selected a frame as reference frame, but wouldn't stack on the comet. I think I need a fresh start by re-installing DSS, try the 32bit version this time. Thanks for the suggestions.

[thomasv]

Right, getting there, de-installed the 64x version and freshly installed 4.1.1 32x version. Selected a few frames for a quick test and it seems to have worked. Just another one of those windows mysteries I guess. Now just need to do it for real.