Telescope: Astro-Tech 8” f/8 Ritchey-Cretien, Orion Atlas EQ-G
Camera: Full Spectrum Modified Nikon D5300
Filter: Orion Imaging Skyglow Filter
Guide scope: Astro-Tech 60mm, Meade DSI Pro II, PHD
Exposure: 13x180sec, ISO 200, saved as RAW
Darks: Internal (Long Exposure Noise Reduction On)
Flats: 32x2sec, Tee shirt flats taken at dawn
Average Light Pollution: Red zone, Bortle 8, poor transparency, bright moonlight
Lensed Sky Quality Meter: 18.2 mag/arc-sec^2
Stacking: Mean with a 2-sigma clip.
White Balance: Nebulosity Automatic
Software: Backyard Nikon, Deep Sky Stacker, Nebulosity, Photoshop
This was the 2nd of 5 first-light images taken with my new to me Astro-Tech 8” f/8 Ritchey-Cretien. The sky conditions were pretty rough with haze and bright moonlight, but I was still able to conduct some basic tests with this new system. This was my first test of the RC8’s narrow-field capability and I cropped the source image to zoom in a bit closer on the nebula to highlight some of the fine detail. Narrow-field imaging of deepsky object can be influenced by the seeing conditions and this limits the usefulness of using larger telescopes for this purpose. The RC8 at f/8 seems to be well suited for my typical sky conditions providing a nice balance of speed and field of view. Also, this was my first opportunity to test the performance of my Nikon 5300a on a warm, muggy summer evening and it performed flawlessly. My cooled ZWO ASI071MC Pro is off being repaired (faulty temperature sensor on the TEC), but so far I’m not missing it (much).
Visually, The Ring appears as a ghostly smoke ring about the size of Jupiter. The nebula itself is not actually a ring, but more likely a torus or a short hour-glass, we just happen to the looking down the long axis, giving the nebula its characteristic shape.