2 replies to this topic

[bosastroguy]

I am trying to stack about 30 dark sky images in DSS, with calibration frames.  The subs were 9 seconds and were obtained over about 5 minutes.  The sky appears to stack without a problem, but the foreground is blurry.  These images were done without tracking.  The tripod was stable, no wind, and the tripod was not moved or bumped during imaging.  I have stacked sky/foreground subs like this before but I dont know why the foreground is blurry this time.  This is a JPG of the TIFF that came out of DSS, no post processing done and a JPG of one of the original RAW subs. Any feedback is appreciated.  

 

  

 

 

Edited by bosastroguy, 26 May 2023 - 04:36 PM.

[t-ara-fan]

Do you know what DSS stacking is? It first aligns all the images based on the star positions.  Then it adds / averages / medians / Winsorizes  / whatevers all those aligned images to give a low noise final result.

 

The stars moved, the tree didn't move.  So the tree is moving relative to the stars.  Ergo - blur.

 

That pic has a nice composition. Photoshop challenge to get a sharp tree.

 

What I would do:

1) shoot a bunch of images of the tree. 

2) move 10m to your left, and shoot the sky.

3) stack "1" in Photoshop, or just take one image

4) stack "2" like you did with DSS

5) stretch and process the stars only pic from "4".

5) cut the tree out of "3" and paste it into "5".

Edited by t-ara-fan, 26 May 2023 - 05:19 PM.

[bosastroguy]

Ok, makes sense.  I have been doing stacking, mostly targets without a foreground, first in Sequator, now in DSS, for the last year or so.  I guess I got lucky stacking to get this image of the Milky Way.  The trees remained sharp on this shot, maybe because the stars in the pond provided another reference for alignment for the software?  Regardless, I have a lot to learn about post processing, but thanks for the explanation.