by Ray Gralak
About a week and a half ago I had my first opportunity to visit Michelle Stone's wonderful dark site, Plettstone. I didn't bring a telescope though. I intended to bring my 18" dob but it never made it into my Expedition since I was so late packing up. I knew there would be others with big scopes from which I could mouch photons. :-)
Instead I just loaded up my Astrophysics 1200 GTO mount, Dell notebook computer, and my SBIG ST-8E CCD camera. I planned to bring at least this equipment because John Gleason was bringing his Astro-Physics 7.1" F7 refractor to try some test images on my mount with my camera.
The skies did not prove at all promising at first. However, we did get some amusement by locating objects *through* the clouds with the GTO feature of the AP mount! ;-)
After a wonderful time talking with others outdoors and inside of Michelle's cabin (boy that fire from the fireplace felt good!) the skies cleared up!
John and I scrambled to get the CCD camera on and focused. We did a pretty good job (but it wasn't perfect as I would find out the next day). We shot a few M42 shots just for kicks then went to the Cone nebula region in Monoceros, where we shot an LRGB image of the area.
For those unaware of the term "LRGB", it stands for Luminance-Red-Green-Blue. The idea is to take a high quality, high resolution luminance shot (black and white exposure) and lower quality, lower resolution color frames. The result is that it takes less time than doing a true RGB shot because each color in the RGB would require much more time to get the same signal/noise as the luminance (which is shot with no filters).
Anyway, for our Cone shot, the luminance was only 33.75 minutes (27x75 seconds) and the RGB was 12 minutes each (4x3 minutes). We would have exposed longer but clouds threatened and we had to cut our session short.
The image was bias and dark frame subtracted but not flat fielded. I used a combination of MaximDL 2.05, MIRA AP 6, and Photoshop 5.5 for image acquisition, registration, and processing. The resultant image was reduced to 66.7% of its original size and can be seen here:
http://www.gralak.com/Astro/CONE-LRGB.jpg
Thanks again Michelle and John!
