DSS Comet stacking On stars AND Comet problem

[frewi808]

I use DSS for my comet stacking, 

I select stack on Comet AND stars what DSS is doing, BUT I still have traces of stars in my pictures, actually it is not trailing but I guess it has something to do with the setting. Can somebody help me to prevent this and how to select the proper setting for a nice clean final image ?

I'm kinda hopeless for now and don't know what to do !

When you look or blow up my pictures you will notice those streaks ..

Freddy Willems

[lensman57]

The traces of stars are caused by the sigma clipping algorithm that DSS uses in order to lock onto the comet for stacking and then transfer the stars. Try to increase the number of the subs or if possible alter the sigma clipping parameters if you know what you are doing. Unless you use a stacking software that allows you to remove the stars with manual control some degree of streaking will remain. You maybe able to clone these out postpones.

A.G

[skybadger]

I have the same problem. I think the answer is to create two images, stretchedd for the tail and one less stretched and then layer them using ps to keep the good stars and the good tail....

[lukebl]

I too would like to know the answer to this.

I see beautiful images of stationary comets with stationary stars, but mine always end up streaky like yours, even with 30+ subs. Someone must know how it's done.

[sharkmelley]

Rather than using a completely automated method (like DSS) a good description of one alternative possible technique is here:  http://www.astrophoton.com/tips/comet_images.pdf

However, in my experience, sigma stacking to remove the stars never works completely and there is always some remnant of trailing that  must be subsequently dealt with manually.  Part of the reason for this is that in light polluted areas the background brightness tends to vary from exposure to exposure and this upsets the sigma calculations.  Sigma stacking works best when the sky background is more or less black, or at least exactly the same brightness in each exposure.

Mark

[happy-kat]

Have you tried first, after registering all frames, marking the centre of the comet on each frame hold shift key as you pick then save then repeat for all lights. When you select stack pick the third option on the comet tab. This should create an image with neat stars and the comet with tail too if you captured it. Hopefully a nice looking image.

[frugal]

I too would like to know the answer to this.

I see beautiful images of stationary comets with stationary stars, but mine always end up streaky like yours, even with 30+ subs. Someone must know how it's done.

The only way I know is to stack everything twice, once stacking the comet (to give a nice image of the comet), and once on the background stars to give a strong background. Then use Photoshop or something similar to combine the two. I would even anticipate that the really nice shots take a series of shots of the area of the sky where the comet was a few days after it has moved on, to ensure that there is no evidence of comet in the background shot.

[Psychobilly]

I have 56x120s to try and stack .. and using comet + stars keeps hanging with <1s shown on time remianing...

Will try again tomorrow...

Peter...