M61, mag. +9.9, is a face-on barred spiral galaxy that belongs to the Virgo cluster of galaxies. It was discovered by Barnabus Oriani while comet chasing on May 5, 1779. Ironically, Charles Messier observed M61 on the same day but mistakenly though he had seen a comet! A few days later he realised his mistake.
M61 is reasonably large galaxy with a diameter of 100,000 light-years, similar to own Milky Way. It has an apparent size of 6.5 x 5.9 arc minutes and is located 52.5 million light-years distant. The galaxy appears visually compact and is one of the finest "small" barred spiral galaxies in the sky for large backyard scopes.
It's located 8 degrees northwest of binary star Porrima (γ Vir - mag. +2.7), 1.25 degrees north-northeast of 16 Vir (mag. +5.0) and best seen during the months of March, April and May.
On dark nights, M61 can be spotted with small scopes as a faint patch of light. Through a 200mm (8-inch) instrument, it appears small with a stellar like core surrounded by a faint halo. Larger scopes of the order of 300mm (12-inch) display the structure in intricate detail with delicate spiral arms visible, surrounding a bright well-defined nucleus.
M61 is classification as a starburst galaxy due to high rates of star formation across its disk. This may be due to interactions with nearby satellite galaxies NGC 4292 and NGC 4303B. It's also a good galaxy for supernovae hunters. To date, seven have been observed with the brightest reaching magnitude +12 in 1964.
M61 Data Table
|Object Type||Spiral galaxy|
|RA (J2000)||12h 21m 55s|
|DEC (J2000)||04d 28m 24s|
|Apparent Size (arc mins)||6.5 x 5.9|
|Number of Stars||>300 Billion|
|Notable Feature||Member of the Virgo cluster of galaxies|