Messier 61 or M61 (also designated NGC 4303) is a spiral galaxy in the constellation Virgo. It has an apparent visual magnitude of 9.7 and its angular diameter is 6x5.5 arc-minutes. M61 lies at an estimated distance of 60 million light years. The Equinox 2000 coordinates are RA= 12h 21.9m, Dec= +04° 28´ which makes M61 best seen during the spring. The Messier Spring Star Chart shows the position of all Messier objects visible during that season.
The image above shows the uncropped view of M61 through the Takahashi E-180 Astrograph (North is up). A 3x enlargement of this image appears to the right.
In spite of its inclusion in the Messier Catalog, this large spiral galaxy was actually discovered by Oriani in 1779. M61 is located in the southern portion of the Virgo Cluster of Galaxies. According to Stoyan et al. (2010), the distance of M61 is 49.6 million light years and its diameter is 94,000 light years. Its estimated mass is 70 billion solar masses. Six supernovae have been observed in M61 between the years 1926 and 2008.
Messier's Description of M61
May 11, 1779
`Nebula, very faint and difficult to perceive. M. Messier mistook this nebula for the Comet of 1779, on the 5th, 6th and 11th of May; on the 11th he recognized that this was not the Comet, but a nebula which was located on its path and in the same point [place] of the sky.'
- Object: M61
- Other Names: NGC 4303
- Object Type: spiral galaxy
- Object Data: Apparent Magnitude = 9.7, Angular Size = 6x5.5 arc-minutes
- Object Position (Equinox 2000): RA= 12h 21.9m, Dec= +04° 28´, Constellation = Virgo
- Date/Time: 2011 Apr 23 at 04:00 UTC
- Location: Bifrost Astronomical Observatory, Portal, AZ
- Mount: Astro-Physics 1200GTO
- Telescope: Takahashi Epsilon 180 Hyperbolic Astrograph
- Camera: Canon EOS 550D (Rebel T2i) (modified with a Baader UV/IR filter)
- Field of View: 1.70° x 2.56° at 1.7 arc-sec/pixel (web version: 10.0 arc-sec/pixel)
- Exposure: 4 x 300s, f/2.8, ISO 800
- File Name: M61-01w.jpg
- Processing (Adobe Camera Raw): Graduated Filter, Vignetting Correction, Noise Reduction, White Balance, Curves
- Processing (Photoshop CS5): Average Images, Curves, Noise Reduction
- Original Image Size: 3454 × 5179 pixels (17.9 MP); 11.5" x 17.3" @ 300 dpi
- Rights: Copyright 2011 by Fred Espenak. All Rights Reserved. See: Image Licensing.