Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Fay on Mar 08, 2009, 08:49:41

Title: Comet Lulin
Post by: Fay on Mar 08, 2009, 08:49:41
This was taken with the Canon, ED80, cls filter, 17x120secs.
I am not too happy with this. I stacked it in DSS, which has a comet aligning facility, but it does not work too well, you get fuzzy trails on the stars, where the program has tried to freeze their position. I layered in PS but there is a lot of trailing to process out & I decided, it makes a dishonest image when too much has to be done.


(http://farm4.static.flickr.com/3354/3336826635_e427000cec_o.jpg)
Title: Re: Comet Lulin
Post by: Carole on Mar 08, 2009, 13:48:07
Well done Fay

Carole
Title: Re: Comet Lulin
Post by: RobertM on Mar 08, 2009, 17:43:25
Very nice image Fay.  How did you keep the comet still ?
Title: Re: Comet Lulin
Post by: Fay on Mar 08, 2009, 18:54:41
Well the nucleus was a bit elongated with movement. I stacked with DSS concentrating on the comet, & then  layered it with the original image.
Stacking in DSS, was supposed to freeze the stars but what it does is make a lot of dull trails below the stars, it is not a very good option. I did then stack, on the comet nucleus,  in Astroart, but the result was a very low luminance comet with stars that were streaked.

With a Maxim stack, the computer nearly ran out of memory & it was very slow & had to be aborted.

DSLR images are a lot different to ccd images, to do.   
Title: Re: Comet Lulin
Post by: JohnP on Mar 08, 2009, 19:19:33
Robert - DSS has a comet stack feature which does a two part stack.. It stacks on stars & then comet nucleus & then overlays... However, It's got problems & leaves streaks (you can see these in Fay's images)

John
Title: Re: Comet Lulin
Post by: RobertM on Mar 08, 2009, 21:22:41
Hi John,  Yes I tried to use DSS, the result was far from what I was expecting i.e. rubbish.  Can't complain thought as it is free...