Stacking 50mm comet shots in DSS

[Jannis]

So, i captured panstarrs this evening, and are currently registering ~700 frames that i managed to get without any ground showing up in the bottom of the frames.

Now, i'm just curious, as to how should i stack these? I use DSS, but i'm a little worried if it will let me select comet stacking or not as the comet have moved so little in my 4-5sec frames that it might noe detect it.

As far as i understood the DSS manual, the comet stacking option will only show up if DSS detects at least 2 frames with a comet in it.

Now, anyway, let's hope it Does detect it and let me stack. But then again, what settions shuold i use? For normal stacking of these short exposures and high ISO i use kappa sigma-clipping. But what options do one have with comet stacking?

From what i read one have only really 3 options - is that correct? And if so, i think going for the "Comet and stars stacking : "star freeze effect" shuold be a good start?

Obviously i could just try and see, but "try and see" with 700 frames is kind of going to take a while, so i ask first as it's still ~40min left of registering the frames...

[Jannis]

Oh my god, is this a joke? DSS doesn't give me any alternative to stack with comet options before i manually select the comet in teh frames.

Does this mean i will have to go through ALL my 700+ frames and select where the comet is in each and every oen of them before i can stack? Or do i just select a coupple of frames, and DSS will find teh comet in teh remaining frames?

[Jannis]

Halfway or so through selecting teh comet in the 706 frames...

*notes to myself - never take 700+ frames of a comet again* >_<

[Jannis]

Finally started stacking now, man that took time. Now i just hope i got long enough exposures to see anything in the final picture. Only 3-5 sec exposures at F/2.8 with ISO 1600 and 3200. Couldn't see much in the single frames, but hopefully a little more clear when my 700 frames have been stacked. Just hope DSS does a good job.

[Jannis]

Ok, now i've tried a ton of things, but i still end up with a very strange picture, and i can't figure out why...

I use comet and star freeze stacking mode, with kappa-sigma clipping. otehr then that, the recommended values.

603 frames, total exposure 1h24m21s. Mix of ISO 1600 and 3200. And mix of 4 and 5 sec subs to have similar exposure.

72 dark frames

30 flat frames

331 bias frames (200 at ISO1600 and 131 at ISO3200)

while stars look good, with both color and shape, why does M31 and the comet look like this? and why isn't the light pollution nice and smooth (have vertical lines, just liek a heavily compressed JPG)?

this image is untouched from DSS other then that i set the saturation to +20 in DSS (wich i've never had any problems with before, and the artifacts are there at the default 0% as well, just obviously with no colors)

i've allready tried comet stacking, and comed + star stacking. only thing i ahve left, wich is running right now, is "normal stacking" where it ignores the comets position.

Hope someone can help me out here.