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The Blue Snowball (NGC 7662)

Planetary Nebula
aka NGC 7662, PN G106.5-17.6, PK 106-17.1, ARO 20
Integrated Visual Magnitude: 8.6
Apparent Diameter: 17"

Mean Surface Brightness: 14.5 mag/arc-sec2
Distance: 4600 ly


Minimum requirements to view: any telescope under any sky


The Blue Snowball is one of the brightest and most fascinating planetary nebulae in the sky.  This planetary has an integrated magnitude of 8.6 packed into a very round ball 17" in diameter.

The non-stellar nature of this object is apparent even  in smaller scopes at low power.  At higher magnifications it appears as a very bright, round ball.  Many observers report a distinct blue-green hue.  In a 6-inch I felt that there was, "some hint of the edges being brighter."  Look for a faint star just to the east of the nebula.


Above: the view in a 6" at 50x. North is down, east is right.  Note how small it is.

My observing notes using my 18-inch:

I had never before observed this planetary nebula in a large instrument. It was a real treat! Even at 82X it was large, bright and obvious.  My notes for 166X simply say "wonderful" and "amazing!" But it was at 333X times that this planetary really shined, despite the poor seeing.  It is nearly round and has a high surface brightness. The edges are not distinct -- they appear lumpy, almost like looking at a barely-resolved ball of yarn.  It has sort of "ropey" edges.  I was surprised that with averted vision I could plainly see a small, dark,  round core (making up perhaps 10% of the object). Another surprise was an apparent bright area just to the south of the dark center.

The image above is taken from the DSS using SkyView. It shows a 1/2o field with the same orientation as above. Note that even thought it is small the nebula (center) has a non-stellar appearance.


This HST image reveals the fine structure inside of the nebula.

Millennium Star Atlas Vol III Chart 1120
Sky Atlas 2000 Chart 9
Uranometria 2000 Vol I Chart 88

Herald-Bobroff Astroatlas B-05 C-21