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

Date: April 24, 2011 8:27:45 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: M13 First LRGB Light with AT8RC

Hi Folks;

After almost a 5 month drought, I finally got to do some DSO imaging last night. This is also my first LRGB Color image taken with the Astro-Tech Ritchey-Chrétien 8" Astrograph.

http://groups.yahoo.com/group/Astro_IIDC/files/DSO/M13_20110424_MJA.jpg 

It was shot at 1560 mm focal length, so it's 0.75 arc seconds per pixel. Measured FWHM is 3 arc seconds. Due to some thin clouds, I had to use 2 second exposures with a Mag 8.5 guide star, which is 2x as long as normal and affected guiding somewhat. Seing was good.

The big difference between my Celestron 8" and the AT8RC  it is the lack of color aberration on the edges and it's ability to stay in focus when you slew across the sky (fixed Mirror in RC scope). I started by focussing on Regulus at 10 pm and the stars were still still sharp after slewing back and forth to 5 am.

I had a 2 hour delay starting up due to some really horrible operational issues (loose dec axis, then deck backlash,  polar alignment was off due to ground settling throwing my GOTO accuracy off, bad guide cable, snagged cables, operator error etc.).

TTYL..

Milton Aupperle