NGC 4449, also known as Caldwell 21, is an irregular galaxy located 12.5 million light-years away in the constellation Canes Venatici. It's part of the M94 Group (or Canes Venatici I Group), a galaxy group close to the Local Group. With an apparent magnitude of +9.4, it's within binocular range but challenging. The galaxy is much easier to spot with telescopes and a rewarding object due to its unusual appearance.

NGC 4449 is intrinsically similar in size and brightness to the Large Magellanic Cloud (LMC), but unlike the Large Magellanic Cloud, it's a starburst galaxy with a high rate of active star formation. It's believed that the current widespread starburst was triggered by interaction or merging of NGC 4449 with a smaller companion or companions. As a result, it contains numerous HII regions and several large star clusters, which contain thousands of young, hot blue stars.

William Herschel discovered the galaxy on April 27, 1788. It's best seen from Northern Hemisphere latitudes during the months of March, April and May.

NGC 4449 (credit:-  NASA, ESA, and The Hubble Heritage Team (STScI/AURA))

Finder Chart for NGC 4449 (credit:- freestarcharts)

Finder Chart for NGC 4449 - pdf format (credit:- freestarcharts)

NGC 4449 is located 3 degrees northwest of Chara (β CVn - mag. +4.2). It has a high surface brightness and therefore, under dark skies, can be spotted with 7x50 or 10x50 binoculars. With binoculars, averted vision is recommended, although at best the galaxy appears as only a tiny diffuse glow. Through a small 100mm (4-inch) telescope, an odd rectangle shape of light with a bright centre is revealed. A 250mm (10-inch) scope at high powers shows several foreground stars along the main axis of the galaxy, with knotty HII regions visible at the northern edge. In total, the galaxy spans 6.2 x 4.4 arc minutes of apparent sky, which corresponds to a spatial diameter of 20,000 light-years.

NGC 4449 provides a peculiar change from the many hundreds of spiral and elliptical galaxies visible to backyard astronomers. It's a remarkable galaxy that's well worth a look.

NGC 4449 Data Table

NGC4449
Caldwell21
Object TypeIrregular Galaxy
ConstellationCanes Venatici
Distance (light-years)12.5 Million
Apparent Mag.+9.4
RA (J2000)12h 28m 11s
DEC (J2000)+44d 05m 36s
Apparent Size (arc mins)6.2 x 4.4
Radius (light-years)10,000
Number of Stars15 Billion
Notable FeatureMember of the M94 Group

Sky Highlights - June 2017

Saturn
Saturn reaches opposition on June 15

The Planets
This Month's Guide

Algol Minima
Algol eclipse dates and times for June

Northern Hemisphere
Evening
Southwest:- Jupiter (mag. -2.2)
Southeast:- Saturn (mag. 0.0)
Midnight
West:- Jupiter
South:- Saturn
Morning
Southwest:- Saturn
Southeast:- Neptune (mag. +7.9)
East:- Venus (mag. -4.3), Uranus (mag. +5.9)

Southern Hemisphere
Evening
North:- Jupiter
East:- Saturn
Midnight
West:- Jupiter
North:- Saturn
Morning
West:- Saturn
Northeast:- Neptune
East:- Venus, Uranus, Mercury (first half of month (mag. -0.4 to -1.2)

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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