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Finally, after many months of waiting for a new SBIG 16803 CCD camera for my RCOS telescope, figuring the back focus, waiting for a spacing adapter and dealing with guide camera focus issues, I think my astro-imaging system is back online. The April new Moon CAV astrosafari provided a great opportunity to test the new camera, guiding, focus and RCOS collimation. I chose M13 for first light LRGB image because those tiny yellow and blue dual population stars in the cluster are a true test of focus, guiding, color balance and collimation, not to mention a new camera! I never imagined other astronomers at CAV would be shooting this beautiful but pedestrian object (M13) with such fervor at this time!! Thanks to a makeshift adapter (de-lensed barlow) from Bill Conrad, I was able to focus my SBIG 402 guide camera and perform four 15-minute guided exposures Luminance, Red, Green and Blue all 1×1 (total – 1 hour) with the new camera operating flawlessly. From the attached results, it appears I put the filters in the correct order. The above image shows tiny focused stars edge-to-edge (click to zoom). I guess the back focus efforts of Barry Riu and Bill Conrad were accurate. My favorite Hubble image of a globular cluster is that taken with the Hubble Space Telescope of Serpens globular M5 showing a dual population of fainter bluish stars and brighter yellow stars (link below). That is what I strived to achieve on M13 (clusters have similar stellar populations). The above mosaic compares my 1 hour CAV RCOS exposure and the Hubble M5 masterpiece as relates to star colors and relative intensities. Faint galaxy IC 4617 can be seen at the lower left of M13 in the full frame shot. The above image of cluster nucleus invades the privacy of the M13 core! I guess I’d call this step one a success for the new camera. For whatever reason, this new camera records many cosmic ray events which my Apogee did not. Wondering if this SBIG is more sensitive than the Apogee with the same CCD chip?
https://www.adamblockphotos.com/m13.html – Mt Lemmon 32-inch RCOS M13 image by Adam Block – gorgeous (although black-clipped)
https://en.wikipedia.org/wiki/Globular_cluster#/media/File:Cosmic_fairy_lights.jpg — Globular Cluster M5 with Hubble Space Telescope
https://www.spacetelescope.org/images/opo0840a/ — Hubble M13 image