Abell 21, the Medusa Nebula in Gemini (Alan Dyer)

Celestial hemisphere: Northern · Constellation: Gemini (Gem) · Contains: NGC 2395

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Abell 21, the Medusa Nebula in Gemini

Link: https://www.amazingsky.com/Amazing-Sky-Images-2-Months/i-s6BsN3T

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Abell 21, the Medusa Nebula in Gemini

Link: https://www.amazingsky.com/Amazing-Sky-Images-2-Months/i-s6BsN3T

This is the faint but large planetary nebula known as the Medusa Nebula, but officially Abell 21 or PK 205+14.1 in Gemini. It was discovered in 1955 and was once classified as a supernova remnant. The very sparse open cluster NGC 2395 is at upper right from the nebula.

The nebula is thought to be 4 light-years across and 1500 light-years away.

This is a blend of filtered and unfiltered exposures: a stack of 4 unfiltered at ISO 1600 for 8 minutes each, and a stack of 8 filtered shots at 10 minutes each and ISO 3200, through the Optolong L-Enhance filter. All with the red-sensitive Canon EOS Ra camera through the SharpStar 100QII astrographic refractor at f/5.8, a quadruplet lens apo refractor. All stacked, aligned and blended in Photoshop.

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Abell 21, the Medusa Nebula in Gemini

Abell 21, the Medusa Nebula in Gemini

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Abell 21, the Medusa Nebula in Gemini

Abell 21, the Medusa Nebula in Gemini

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