The Needle Galaxy is a barred spiral galaxy located approximately 30 – 50 million light-years away in the constellation Coma Berenices. It is one of the best-known edge-on spiral galaxies in the night sky. The galaxy is catalogued as NGC 4565 in the New General Catalogue and Caldwell 38 in the Caldwell catalogue of deep sky objects visible in amateur telescopes.
The Needle Galaxy has an apparent magnitude of 10.42 and an apparent size of 15.9 by 1.85 arcminutes. It was named for its narrow appearance. The galaxy appears almost exactly edge-on when seen from Earth. It lies in the same region of the sky as the Coma Star Cluster, not far from the North Galactic Pole. It is one of the brightest members of the Coma I Group of galaxies.
The giant spiral galaxy has a bright yellowish central bulge glowing behind prominent dust lanes that cut across the galactic core. The presence of the central bar was confirmed by observations with the Spitzer Space Telescope, which also revealed the existence of a pseudobulge within the box-shaped bulge. The Milky Way would appear similar if it were seen from the same angle.
NGC 4565 is the brightest and finest edge-on spiral galaxy in the sky. It is more luminous than the Andromeda Galaxy (Messier 31), but similar in size. It contains about 240 globular clusters, more than our own Milky Way galaxy. These clusters stand out in images because the galaxy appears edge-on.
The Needle Galaxy is the second-brightest galaxy in the Coma I Group. The galaxy group appears in the same region of the sky as the Coma Star Cluster (Melotte 111), a nearby open cluster that dominates the western portion of Coma Berenices.
The center of the Coma I Group lies approximately 47.3 light-years from the solar system. The group contains mostly spiral galaxies, with few lenticular and elliptical members. The brightest galaxy in the group, the intermediate barred spiral galaxy NGC 4725, has an apparent magnitude of 10.1. It appears east of the Needle Galaxy.
The Coma I Group lies within the Virgo Supercluster. It is currently infalling into the Virgo Cluster and will eventually merge with it.
The Needle Galaxy was discovered by the German-born British astronomer Sir William Herschel on April 6, 1785. Herschel discovered the brighter NGC 4725 on the same day.
NGC 4565 has at least two smaller satellite galaxies and is interacting with one of them. The galaxy has a slightly warped and extended disk, likely a result of the interaction with the smaller galaxies and other members of the Coma I Group.
The Needle Galaxy was imaged with the NASA and ESA Hubble Space Telescope as part of Hubble’s Caldwell Catalog series.
The Needle Galaxy appears in the same line of sight as the Coma Berenices Cluster, an open cluster that stretches across 7.5 degrees of the sky and occupies a good portion of Coma Berenices. The galaxy lies 3 degrees southeast of Gamma Comae Berenices, the brightest star in the constellation, and about 3 degrees from the North Galactic Pole. The orange giant is the brightest star in the region between Cor Caroli in Canes Venatici and Denebola in Leo.
The best time of the year to observe the Needle Galaxy and other galaxies in Coma Berenices is during the month of May, when the constellation is high above the horizon in the evening.
The Needle Galaxy can be spotted in small telescopes. It appears as a very narrow streak of light contrasted against the dark sky at the eastern edge of the Coma Berenices Cluster. The central bulge may be seen in 4-inch telescopes in good conditions but is better viewed in larger instruments. An 8-inch telescope will reveal the bright nucleus and hints of the dark dust lane. The details in the dark lane can be observed in larger telescopes. A 14-inch telescope may reveal a satellite galaxy, NGC 4562, about a quarter of a degree west-southwest of NGC 4565.
Needle Galaxy – NGC 4565
|Right ascension||12h 36m 20.8s|
|Declination||+25° 59′ 16″|
|Apparent size||15′.90 × 1′.85|
|Distance||42.7 ± 12 million light-years (13.1 ± 3.7 megaparsecs) or 53 ± 4 Mly (16.2 ± 1.3 Mpc)|
|Helio radial velocity||1,230 ± 5 km/s|
|Names and designations||Needle Galaxy, NGC 4565, Caldwell 38, PGC 42038, UGC 7772|