Planetary Nebula Of The Week - 10

THE 'BLUE SNOWBALL' NEBULA
**   NGC 7662  **

Constellation Of Andromeda ( Daughter of Cassiopeia)

The Blue Snowball From And Above The Pale Blue Dot

8/9/96 at the Orange County Astronomers (OCA) observatory near Anza, CA. 22" Ritchey-Chretien (F/5-ish) with CB245 camera.	Hubble Space Telescope image of NGC 7662 - Dr. Bruce Balick, (U. of Washington), STScI, NASA..

Location Finder Chart For NGC 7662 From Megastar, Version 4

Additional 'Factinos':

• Distance: Estimated to be 3,900 light years from our solar system.
• Radial Velocity: 13 km/sec, moving towards our solar system.
• Expansion Velocity: Approximately 26 km/sec.
• Discovered by Herschel, 1784
• Uranometria 2000.0 Chart No. 88
• NGC/IC description is "!!! O or ®, vB, pS, R, blue, variable Nucl" , which tranlates
  to 'a magnificent planetary nebula or annular / ring nebula, very Bright, pretty Small,
  Round, blue, variable nucleus'.

Observing Notes From (1) Steve Gottlieb, and (2) Lew Gramer
(1) NGC 7662 = PK 106-17 1 = Blue Snowball 23 25.9 +42 33
17.5": extremely bright, very high surface brightness, fairly small, easily takes very high power. At 410x, the planetary appears weakly annular with a slightly darker center. There is a second outer shell which exhibits
subtle structure due to an irregular surface structure, blue-green color is evident.
13": darker center, faint outer shell. 9/11/82
8": slightly darker center at 300-400x, irregular surface brightness. 9/25/81

(2)Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-07-31/08-01, 05:30 UT
Location: Savoy, MA, USA (42N, elev 700m)
Site classification: rural
Limiting magnitude: 7.2 (zenith)
Seeing: 7 of 10 - pretty good, with intermittent haze
Moon up: no
Instrument: 20" f/5 Tectron truss-tube dob Newtonian reflector
Magnification: 70x, 210x. 360x, 420x
Filters used: None, UHC, OIII
Object: ngc7662 (Blue Snowball planetary)
Category: Planetary nebula [4+3]
Constellation: And
Data: mag 9.2 size 32"x28" (halo 130")
RA/DE: 23h26m +42o32m
Description:
The sky haze played many contrast tricks on this object tonight, showing a disk at 210x and 360x which alternated between being distinctly annular and completely even in brightness! In times when annularity was most pronounced, the nebulosity in n7662's central area showed occasional striations to averted vision. The
bright area on the NE inner edge was continually very distinct, but seemed nearly stellar even at 360x! With the OIII at 420x, this NE brightening became clearly non-stellar, with irregular outlines merging into the surrounding ring. The central star was definitely visible to averted & concentrated vision at 420x, but only WITHOUT a filter. The outer disk of the Snowball seemed to be remarkably SYMMETRIC (non-elongated) this morning, although hints
of an outer halo to the NW and SE could be seen merging with the outer edges of the bright disk when an OIII was used. Lovely pn!

Thank You, Gentlemen!

Two Amateur's Diverse Methods of Capturing A Snowball

Larry McHenry is a great sketcher of astronomical objects. His web site has a great variety of detailed  NGC sketches.	Ed Grafton is a Texas amateur who is concentrating on CCD imaging and has some incredible images at his web site.

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Douglas Snyder    July 1998