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NGC 2371-2 (Gemini Nebula)
Planetary Nebula
aka NGC 2371, PN G189.1+19.8, PK 189+19.1
RA: 07h25m34.7s, Dec: +29°29'26" (2000) in Gemini
Galactic lon: +189°09', Galactic lat: +19°51'
Magnitude: 13.00
Size: 44"
Magnitude of central star: 14.8
Distance: 4400 ly
Mean Surface Br. 21.0 Mag/arc-secē

Minimum requirements to detect: 6-inch telescope under dark skies


NGC 2371-2 is an amazing planetary nebula when viewed in a large aperture instrument.  This 13th magnitude object in Gemini appears as a pair of teardrop-shaped lobes that span 44".  Between the lobes lies a 14.8 magnitude star.  I've seen this relatively unknown jewel of a planetary referred to as both the Gemini and the Peanut.  Both names are descriptive.  I prefer the name Gemini because it is also in this constellation.  

The Gemini is easy to find to the southwest of Castor.  Start at Castor and use the two bright stars that form an equilateral triangle to the southwest as a guide to tell you which direction to sweep.  The nebula lies between the widest pair of three 7th magnitude stars that lie in a straight line.


The view in a six inch at 50x.  North is down and east is to the right.

Detecting this nebula is a challenge in a six inch.  Only a faint haze is visible under the darkest conditions.  The southwest lobe is the brighter of the two and the most likely to be visible in small scopes.

In large apertures the bipolar structure is seen clearly.   Use as much magnification as seeing will permit.  A challenge for large instruments is to detect the faint bridge of nebulosity that stretches between the lobes and a faint halo that surrounds the entire object.  For a real challenge, have a try at the faint patches that lie at right-angles to the lobes (see image below).  

This color DSS image shows a 5' field.  North is down, east is to the right.  Most observers will only see the bright lobes.

Millennium Star Atlas Vol I Chart 130
Sky Atlas 2000 Chart 5
Uranometria 2000 Vol I Chart 100
Uranometria 2nd Ed. Chart 75
Herald-Bobroff Astroatlas B-05 C-22