M62 is a magnitude +6.5 globular cluster in the constellation of Ophiuchus at the border with Scorpius. It's located close to the centre of the Milky Way which may be the reason why it's one of the most irregular shaped globulars known. At a distance of only 6,100 light years from the galactic centre, M62 is subject to large deforming tidal forces. From Earth, the globular is much further away at 22,200 light-years.
M62 is visible with binoculars as a faint small fuzzy ball of light. However, since it's located amongst the rich starfields of the Milky Way it can easily be missed. It's best seen from tropical and southern hemisphere latitudes during the months of May, June and July. For mid latitude northern hemisphere based observers M62 is a tricky object. With a declination of 30 degrees south it's doesn't rise particularly high above the southern horizon, therefore never well situated for observation.
The globular was discovered by Charles Messier on June 7, 1771. However, he didn't accurately measure its position until 1779 when it was added to his catalogue. William Herschel first resolved M62 into stars describing it as a miniature version of M3. Finding M62 can be challenging as there are no bright stars right next to it. It can be located by imagining a right angle triangle formed by connecting Antares (α Sco - mag. +1.0) with epsilon Sco (ε - mag. +2.3) and M62. Antares is 7.5 degrees northwest of M62 and ε Sco is 4.75 degrees southwest of M62.
Positioned 4.5 degrees north of M62 is slightly fainter but larger globular cluster M19 (mag. +7.2).
When viewed through a 80mm (3.1-inch) telescope, M62 appears as a diffuse ball of light with a bright core. On nights of good seeing and transparency a 200mm (8-inch) scope at medium to high magnifications will begin to resolve the outer edges. Averted vision helps significantly but larger size amateur scopes are required for better resolution to obtain a deeper view. Also noticeable is the oval shape of the cluster with the long axis orientated in the north-south direction. The center of the cluster appears condensed and it's a more compact globular than neighbour M19.
In total M62 covers 15 arc minutes of sky which corresponds to a spatial diameter 96 light-years. Visually it appears smaller, covering 8 to 10 arc minutes of apparent sky. The globular contains a high number of variable stars of which at least 89 are know, many of them RR Lyrae type. It's also likely that at some point in its history M62 has undergone a core collapse (like M15, M30 and M70).
M62 Data Table
|Object Type||Globular cluster|
|RA (J2000)||17h 01m 12.5s|
|DEC (J2000)||-30d 06m 44s|
|Apparent Size (arc mins)||15 x 15|
|Number of Stars||150,000|
|Notable Features||Very irregular in shape. Contains a high number of variable stars (at least 89)|