Hemisphere:  Northern  ·  Constellation: Gemini (Gem)
PK205, medusa nebula, 


PK205, medusa nebula
Powered byPixInsight

PK205, medusa nebula

Technical card

Imaging cameras: Atik 314L+

Mounts: Sky-Watcher EQ6 Syntreck

Focal reducers: FS78-f6

Software: PixInsight  ·  PHD guiding  ·  DeepSkyStacker  ·  Starry Night Pro 6  ·  Maxim DL

Filters: Baader Planetarium H-Alpha Filter

Accessory: Lunatico Astronomia Guidescope

Dates:Feb. 1, 2012

Frames: 44x900" (11h)

Integration: 11h

Avg. Moon age: 8.56 days

Avg. Moon phase: 62.36%

Basic astrometry details

Astrometry.net job: 123986

RA center: 07h28m54s.7

DEC center: +13°1727

Pixel scale: 2.933 arcsec/pixel

Orientation: 139.972 degrees

Field radius: 0.609 degrees

Resolution: 620x453


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.[4] The braided serpentine filaments of glowing gas suggests the serpent hair of Medusa found in ancient Greek mythology.

Until the early 1970s, the Medusa was thought to be a supernova remnant. With the computation of expansion velocities and the thermal character of the radio emission, Soviet astronomers in 1971 concluded that it was most likely a planetary nebula.[4]

As the nebula is so big, its surface brightness is very low, with surface magnitudes of between +15.99 and +25 reported. Because of this most websites recommend at least an 8-inch (200 mm) telescope with an [O III] filter to find this object although probably possible to image with smaller apertures.


Sky plot

Sky plot


PK205, medusa nebula,