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Abell 21 - The Medusa Nebula - Planetary Nebula in Gemini
by Bob and Janice Fera
Officina
Stellare RC-360AST 14" f/8 Ritchey Chretien Cassegrain
with two-element field flattener
Apogee Alta U16M CCD Camera
Astrodon Filters
Ha-OIII-RGB Composite - 390:450:40:40:40 minutes
Sub Exposures: Ha:13x30m OIII:15x30m RGB:8x5m
Image acquired with CCDAutopilot
Processed in CCDstack and Adobe Photoshop
Taken December 31, 2013, January 1-3, 5, 2014 from Eagle Ridge Observatory, Foresthill, CA
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