Daily Archives: March 2, 2015

SH2-274, Medusa Nebula


The Medusa Nebula is a large planetary nebula in the constellation of Gemini on the Canis Minor border. It also known as Abell 21 and Sharpless 274. It was originally discovered in 1955 by UCLA astronomer George O. Abell, who classified it as an old planetary nebula. The braided serpentine filaments of glowing gas suggests the serpent hair of Medusafound in ancient Greek mythology.

Imaging telescopes or lenses: Astro-Tech AT8IN
Imaging cameras: QHY CCD QHY8
Mounts: CGEM
Guiding telescopes or lenses: Astro-Tech AT8IN
Guiding cameras: QHY CCD QHY5L-II
Focal reducers: Baader Planetarium MPCC Mark III
Software: Photoshop CS6,  Main Sequence Software SequenceGeneratorPro,  Stark Labs Nebulosity 3.1.X,  ADGSoftware PHD2 (OpenPHD)
Filters: Baader SII 8nm,  Orion O-III 7nm,  Orion H‑Alpha 7nm
Accessories: Orion Thin Off-Axis Guider (TOAG),  Orion Filter Wheel 5-place 2″ filter wheel
Resolution: 3020×1937
Dates: Feb. 12, 2015,  Feb. 14, 2015,  Feb. 20, 2015
Baader SII 8nm: 6×2700″ -29C bin 1×1
Orion H‑Alpha 7nm: 8×2700″ -24C bin 1×1
Orion O-III 7nm: 8×2700″ -21C bin 1×1
Integration: 16.5 hours
Darks: ~5
Flats: ~11
Flat darks: ~11
Bias: ~100
Avg. Moon age: 15.72 days
Avg. Moon phase: 28.01%
Bortle Dark-Sky Scale: 5.00
RA center: 112.254 degrees
DEC center: 13.287 degrees
Pixel scale: 1.856 arcsec/pixel
Orientation: 177.233 degrees
Field radius: 0.925 degrees
Locations: Backyard, Gainesville, FL, United States
Author: Serge Caballero

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