M91
NGC 4548
天体データ
- カタログ符号
- M91
- タイプ
- Galaxy
- 星座
- Coma Berenices
- 等級
- 10.2
- 赤経
- 12h 35m 26.4s
- 赤緯
- +14° 29' 47.0"
- 距離
- 63,000,000 光年
- 角度サイズ
- 5.4
サーベイ画像
サーベイ画像を読み込み中…
M91について
説明
M91 is a barred spiral galaxy in Coma Berenices, about 63 million light-years from Earth. It has a prominent central bar and well-defined spiral arms, making it one of the brighter barred spirals in the Virgo Cluster. The galaxy spans about 100,000 light-years. M91 was a 'lost' Messier object for nearly two centuries due to a position error.
観測のコツ
Located about 1 degree south-southeast of M88 in the Virgo Cluster. In a telescope it appears as a moderately bright, oval glow with a bar-shaped central region visible in 8-inch or larger telescopes. The spiral arms are faint and require excellent conditions. It can be confused with nearby galaxies without careful chart comparison. Best observed from March through June.
歴史
Cataloged by Charles Messier on March 18, 1781, but with incorrect coordinates that pointed to empty sky. M91 was 'lost' until William C. Williams identified it in 1969 as NGC 4548 by correcting Messier's position error. Some historians had previously speculated it was a comet or even a duplicate observation of M58.
豆知識
M91 was the last 'lost' Messier object to be identified. Messier apparently made a reference frame error, recording the position relative to M89 instead of M58. When the correction is applied, the position matches NGC 4548 perfectly. M91 has the lowest surface brightness of any galaxy in the Messier catalog.
コミュニティ写真 (1)
Credit: NASA, ESA, and J. Lee (California Institute of Technology). License: CC BY-SA 4.0. (Wikimedia Commons)
Skybred Feb 28, 2026