NGC 7662 is a planetary nebula located in Andromeda. It's also known as the Blue Snowball Nebula or Snowball Nebula and at apparent magnitude +8.6 is one of the brightest examples of its type and therefore a popular target for both amateur and professional astronomers. NGC 7662 is positioned 0.5 degrees southwest of star 13 And (mag. +5.7) and was discovered by William Herschel on October 6, 1784. It's best seen from Northern Hemisphere latitudes and appears high in the sky during the months of October, November and December.

NGC 7662 (credit:- Mike Landherr/NASA/ESA/ESO)

NGC 7662 is visible with binoculars appearing star-like. When viewed through an 80mm (3.1-inch) scope at high powers it appears slightly elliptical and greenish in colour. The non-stellar nature of the object is clearly visible. However, even on nights of good seeing it appears no more than an out of focus fuzzy green star. In total the planetary spans 32 x 28 arc seconds of apparent sky.

A 200mm (8-inch) size scope or greater at a magnification of at least 250x is recommended to show the dark centre of NGC 7662. The Blue Snowball Nebula is structurally complex and is actually a doubled ringed planetary which means it consists of a bright central ring of gas surrounded by a much larger, dimmer and hazier envelope. The other halo along with the dim central star (mag. +13) require large amateur telescopes to be seen.

Finder Chart for NGC 7662 (credit:- freestarcharts)

Finder Chart for NGC 7662 - pdf format (credit:- freestarcharts)

Like with many planetary nebulae it's difficult to accurately determine distance. NGC 7662 is estimated to be between 2,000 and 4,000 light-years away and therefore has a spatially diameter between 0.35 and 0.70 light-years. The object is number 22 in the Caldwell catalogue.

NGC 7662 Data Table

NGC7662
Caldwell22
NameBlue Snowball Nebula
Object TypePlanetary Nebula
ConstellationAndromeda
Distance (light-years)2,000 -> 4,000
Apparent Mag.8.6
RA (J2000)23h 25m 54s
DEC (J2000)42d 32m 06s
Apparent Size (arcsecs)32 x 28
Radius (light-years)0.175 -> 0.35
Other NameSnowball Nebula

Sky Highlights - July 2017

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for July

Meteor Shower
Southern Delta Aquariids (Aquarids) meteor shower peaks on July 29

Northern Hemisphere
Evening
West:- Mercury (mag. -0.5 to +0.3) (second half of month)
Southwest:- Jupiter (mag. -2.0)
South:- Saturn (mag. +0.2)
Midnight
West:- Jupiter
South:- Saturn
East:- Neptune (mag. +7.8)
Morning
Southwest:- Saturn
South:- Neptune
Southeast:- Uranus (mag. +5.8)
East:- Venus (mag. -4.1)

Southern Hemisphere
Evening
West:- Mercury (second half of month)
Northwest:- Jupiter
East:- Saturn
Midnight
West:- Jupiter
North:- Saturn
East:- Neptune
Morning
West:- Saturn
North:- Neptune
Northeast:- Venus, Uranus

Deep Sky

Small telescopes:-
Messier 13 - M13 - Great Hercules Globular Cluster
Messier 92 - M92 - Globular Cluster
Messier 11 - M11 - The Wild Duck Cluster (Open Cluster)
Messier 7 - M7 - The Ptolemy Cluster (Open Cluster)
Messier 6 - M6 - The Butterfly Cluster (Open Cluster)
Messier 4 - M4 - Globular Cluster
Messier 8 - M8 - Lagoon Nebula (Emission Nebula)
Messier 16 - M16 - Eagle Nebula (Emission Nebula with Open Cluster)
Messier 20 - M20 - Trifid Nebula (Emission and Reflection Nebula)

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