From: "milton_aupperle" <milton@outcastsoft.com>

Date: October 7, 2010 1:32:44 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: NGC 6992 Veil East North part and reprocessed South Part

Hi Folks;

It was clear again last night, but turbulence was in the mediocre range (FWHM 6 to 6.9 Arc Seconds versus 4.4 to 4.9 arc seconds Sept 30 ). I managed to capture the North half of the East Veil nebula:

http://tech.groups.yahoo.com/group/Astro_IIDC/files/DSO/VeilEastNorth_20101006_MJA.jpg

This time I stacked the RGB color channels and used a 30% Gradient removal when stacking ("Apply XXXX gradient leveling to reduce uneven illumination." see Page 45 / 46 of the Astro IIDC manual).

I also reprocessed the NGC6995 / Veil East South RGB movies using the same gradient removal as I'm now sure that Red patch in the upper right corner is not real.

Here is the new version:

http://tech.groups.yahoo.com/group/Astro_IIDC/files/DSO/VeilEastSouthV2_20100930_MJA.jpg

and here is the old original red version:

http://tech.groups.yahoo.com/group/Astro_IIDC/files/DSO/NGC6995_LRGB_20100930_MJA.jpg

You can see the red patch is "gone" now and because it's gone, I can push the processing a bit further to bring out the nebula.

The issue is that I need to shoot drastically different RGB exposure times to balance the star colors with the Grasshopper EXHAD CCD and the LRGB AstroDon E Filters (7 minutes Red, 4 minutes Red, 3 minutes Blue Binned 2x2). Then add in light pollution which raises the background levels and you wind up with marked gradients across the image.

TTYL..

Milton Aupperle