NGC 4559 is a spiral galaxy located in the constellation Coma Berenices. At mag. +10.0 it can be spotted with binoculars, but is challenging, requiring dark skies and patience. However, its high surface brightness does somewhat help. The galaxy is a nice telescope target that offers something for all sizes of backyard instruments.

NGC 4559 was discovered by William Herschel on April 11, 1785 and is estimated to be 30 million light-years distant. It's best seen from northern locations during the months of March, April and May.

NGC 4559 (credit:- NASA, ESA, and The Hubble Heritage Team (STScI/AURA))

Finder Chart for NGC 4559 (credit:- freestarcharts)

Finder Chart for NGC 4559 - pdf format (credit:- freestarcharts)

NGC 4559 is located at the northeastern edge of the large naked eye Coma Star Cluster, which contains approx. 50 members including 12,13,14,16 and 21 Comae Berenices. Positioned a couple of degrees to the west is Gamma Comae Berenices (γ Com - mag. +4.4). The superb Needle Galaxy (NGC 4565) is located 2 degrees south of NGC 4559.

Through a 100mm (4-inch) scope at low magnifications, NGC 4559 is obviously oval shaped, spanning 10 x 4 arc minutes. The nucleus appears condensed, bright and surrounded by a hazy stream of soft light. Larger backyard scopes show significant mottling within the halo, which corresponds to the numerous dust lanes and bright nebulae located within the galaxy's arms. There are three 13th magnitude stars visible that curve in shape at the southeastern edge of the galaxy.

In 1941, a mag. +13.2 supernova (SN 1941a) was seen in NGC 4559. The galaxy is number 36 in the Caldwell catalogue.

NGC 4559 Data Table

Object TypeSpiral Galaxy
ClassificationSAB(rs) cd
ConstellationComa Berenices
Distance (light-years)30 Million
Apparent Mag.+10.0
RA (J2000)12h 35m 57s
DEC (J2000)+27d 57m 35s
Apparent Size (arc mins)10.7 x 4.4
Radius (light-years)45,000
Number of Stars250 Billion

Sky Highlights - September 2017

Neptune reaches opposition on September 5th

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for September

Northern Hemisphere
West:- Jupiter (mag. -1.7)
Southwest:- Saturn (mag. +0.5)
East:- Neptune (mag. +7.8)
South:- Neptune
East:- Uranus (mag. +5.7)
West:- Neptune
South:- Uranus
East:- Venus (mag. -3.9), Mars (mag. +1.8) (from second week), Mercury (mag. +0.5 to -1.3) (from second week)

Southern Hemisphere
West:- Jupiter
Northwest:- Saturn
East:- Neptune
West:- Saturn
North:- Neptune
Northeast:- Uranus
West:- Neptune
Northwest:- Uranus
Northeast:- Venus
East:- Mars (end of month)

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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