Saturday, July 05, 2008

Dumbbell 4th July 2007

Here's another M27 taken on 4th July, (Happy Birthday Leanne).
This is a DSS combination of the previous set of images taken on the 01/07/08 and a set of 28 x 2minute 1600ISO images taken on the 4th. I polar aligned the scope before taking the images, and therefore I didn't use DEC control in PHD. But there was a very small amount of trailing that I could detect, which had to be removed in PS using layering. Because of this the results are not quite as good as I hoped (the stars look like squashed eggs).
Still you live and learn.
The two set of images were quite a bit out of registration, but DSS matched them up perfectly.

Removing star trails:-
Using PS in layers duplicate the image (called a background copy), next change the background copies blending mode to darken,
with background copy highlighted, select the offset tool in filters
(zoom in 500% on the image "Ctrl +") and adjust the horizontal/vertical pixels
(undefined areas set to wrap around).
For the full size picture I used Horizontal of "1" and Vertical of "2"...this will vary depending on the size of the trails and what direction they are heading....i.e. up and down...on a 45....sideways.... etc. with the two settings until the trails are diminished or can use negative numbers.
Once you have the star shape where you want it, zoom back out, then flatten the image and save.
If the filter takes it a tad too far, go to the ..... Edit>Fade filter function and this will decrease the amount. (this must be done before you flattern) with it a couple of times.