Deep Sky Object in Winter
Medusa Nebula (PK205+14.1 in Gemini)
|Date & Time: ||Dec 20 2014, from 25:23 to 26:06 JST(+0900)
|Composed 8 shots with 6 minutes exposed|
|Optical: ||Meade 25cm(10") Schmidt-Cassegrain with a conversion lens (f=1600mm, F6.3)
|with BaaderPlanetarium Moon&Skyglow filter|
|Auto-guided with Meade LX200 Equatorial & Pictor 201XT
|Digital Camera: ||Canon EOS 600D (Remodeled)
|Location: ||Ooizumi, Hokuto city, Yamanashi pref.
|Camera Settings: ||Recording format...14bit CCD-RAW, converted to 16bit TIFF(5184×3456)|
This is a large planetary nebula lying around south of Gemini nearby Canis Minor.
You can estimate about 5 arc minutes in diameter from the image, it's one of the largest planetary nebulae in heavens.
But strange to say, the object is not very well known so doesn't be registered in NGC catalogue.
The code of this nebula "PLN" is a minor catalogue of "Strasbourg Catalogue of Planetary Nebulae" that contains 1445 planetary nebulae.
|PK205+14.1(Sh2-274) / Planetary Nebula|
|R.A.||07h 29m 0.3s (2000.0)|
|Dec.||+13° 14' 46" (2000.0)|
|Apparent Size||about 5'|
The nebula has an apparent shape of circle, but fairly bright in southeast part so this image shows like the crescent moon.
And the nebula is often called "Medusa Nebula".
Medusa is a name of monster exterminated by Perseus, but a reason why the nebula has such a nickname is not clear.