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Re: Help with IC 4812 and surrounding goodies

Posted: Tue Jun 16, 2015 6:02 am
by admin
Hi,

Loading up the data, it appears it has already been stretched. Any idea what may have caused that?

It's pretty challenging data indeed with some very strong undulating gradients going on. Did you take flats?

Re: Help with IC 4812 and surrounding goodies

Posted: Tue Jun 16, 2015 12:29 pm
by chrischarlesjax
No idea why it appears stretched. The original autosave file wouldn't open in StarTools (I think the default save is as a 32 bit TIFF), so I saved over it as a 16 bit TIFF, but did not make any changes to the image. I used a Celestron Nightscape OSC with a KAI-10100 chip. The autosave file in the dropbox was unstretched. I took flats, but they made things worse so this stack was without. I may go in and re-stack it with flats again with some different settings I typically use median kappa sigma clipping in DSS, but I wonder if it was set to median this time...hmm When I try to remove hot pixels set to 1 pixel and 50%, stars get removed in the process from the stacked image...or rather, the center of stars.

Re: Help with IC 4812 and surrounding goodies

Posted: Tue Jun 16, 2015 12:43 pm
by chrischarlesjax
As a point of reference, here is what I came up with, but clearly it's a fairly noisy image especially towards the bottom of the frame.
IC 4812.jpg
IC 4812.jpg (243.76 KiB) Viewed 2919 times

Re: Help with IC 4812 and surrounding goodies

Posted: Tue Jun 16, 2015 1:35 pm
by Cheman
The file that I got from Chris and put in dropbox, when checking properties, says " Picture saved with settings applied." from DSS. Could this be the reason the image appears to have been stretched?
Che

Re: Help with IC 4812 and surrounding goodies

Posted: Tue Jun 16, 2015 2:53 pm
by chrischarlesjax
I always select the apply adjustments setting rather than the embed setting, so that could be it is being read as stretched when it actually wasn't.

Re: Help with IC 4812 and surrounding goodies

Posted: Thu Jun 18, 2015 1:57 am
by admin
Cheman wrote:The file that I got from Chris and put in dropbox, when checking properties, says " Picture saved with settings applied." from DSS. Could this be the reason the image appears to have been stretched?
Che
Could well be! (I opened the .FTS)