NGC 663, mag. +7.1, is a young open cluster that's one of a number of bright clusters that can be seen with binoculars in the constellation of Cassiopeia. It contains at least 80 stars visible in amateur telescopes spread over a diameter of 16 arc minutes. A 100mm (4-inch) scope reveals a bright rich grouping immersed in a hazy glow with many stars resolvable. NGC 663 is striking in larger scopes appearing reasonably concentrated towards the centre with dozens of stars spread across the cluster face. Double star Struve 152 is a cluster member.

NGC 663 (credit - Hunter Wilson)

NGC 663 is located 3 degrees northeast of Ruchbah (δ Cas - mag. +2.7) and 3 degrees southwest of epsilon Cas (ε Cas - mag. +3.4). Positioned just north of the cluster is NGC 654 (mag. +6.5) with NGC 659 (mag. +7.9) to the south. Also located nearby next to Ruchbah is M103 (mag. +7.4). All of these open clusters are visible in binoculars.

From most northern temperate latitudes NGC 663 is circumpolar and therefore visible all year round; it appears highest in the sky during October, November and December. From Southern Hemisphere latitudes the cluster appears at best low above the northern horizon and from some more southerly locations it never even rises at all.

NGC 663 is located 7,000 light-years distant. It's estimated to be 20 Million years old and is number 10 in the Caldwell catalogue. The cluster was discovered by William Herschel on November 3, 1787. It's believed to form part of the stellar association Cassiopeia OB8, which also contains M103, NGC 654, NGC 659 and some supergiant stars scattered between them. NGC 663 is interesting to professional astronomers as it also contains a high number of Be stars and some blue stragglers.

NGC 663 Finder Chart - (credit - freestarcharts)

NGC 663 Finder Chart - pdf format (credit - freestarcharts)

NGC 663 Data Table

Object TypeOpen Cluster
Distance (light-years)7,000
Apparent Mag.7.1
RA (J2000)01h 46m 16s
DEC (J2000)61d 13m 06s
Apparent Size (arc mins)16 x 16
Radius (light-years)16.5
Age (years)20 Million
Number of Stars>80
Other NameCollinder 20

Sky Highlights - March 2017

Comet 41P/Tuttle-Giacobini-Kresak now visible with binoculars as it heads towards perihelion

Mercury heading towards greatest elongation east

Minor Planet
Vesta now visible with binoculars and small telescopes.

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for March 2017

Northern Hemisphere
West:- Venus (mag. -4.8 to -4.1 - first half of month), Mars (mag. +1.3 to +1.5), Uranus (mag. +5.9), Mercury (mag. -1.5 to -0.4 - second half of month)
Southeast:- Jupiter (mag. -2.3 to -2.5)
Southwest:- Jupiter
Southeast:- Saturn (mag. +0.5)

Southern Hemisphere
West:- Venus (first half of month), Mars, Uranus
North:- Jupiter
East:- Saturn
West:- Jupiter
Northeast:- Saturn
East:- Neptune (mag. +8.0 - second half of month)

Deep Sky
Naked eye / binoculars:-
Melotte 111 - Mel 111 - The Coma Star Cluster (Open Cluster)
Messier 44 - M44 - The Praesepe (Open Cluster)

Messier 67 - M67 - Open Cluster
Messier 51 - M51 - The Whirlpool Galaxy (Spiral Galaxy)
Messier 97 - M97 - The Owl Nebula (Planetary Nebula)
Messier 101 - M101 - The Pinwheel Galaxy (Spiral Galaxy)
Messier 65 – M65 – Spiral Galaxy
Messier 66 - M66 - Intermediate Spiral Galaxy
Messier 95 - M95 - Barred Spiral Galaxy
Messier 96 - M96 - Intermediate Spiral Galaxy
NGC 4244 - Spiral Galaxy
NGC 4565 - Needle Galaxy - Spiral Galaxy

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