NGC 6025, mag. +5.1, is a naked eye open cluster located in the southern constellation of Triangulum Australe. It's essentially a southern-based object that's a nice target for binoculars and small scopes. From all locations below 30S, NGC 6025 is circumpolar and therefore never sets. The cluster can also be seen from northern locations, although from latitudes greater than 30N it never rises above the horizon.
NGC 6025 is 2,500 light-years distant and is best seen between the months of May and July. It was discovered by Abbe Lacaille during his 1751 / 1752 South African tour.
Once you've located the main triangular shape of Triangulum Australe, it's easy to find NGC 6025. The cluster straddles the Triangulum Australe / Norma constellation boundary and is positioned just over 3 degrees north-northeast of the northernmost star in triangle, Beta Trianguli Australis (β TrA - mag. +2.8). Located 10 degrees further west is Alpha Centauri, or as it's occasionally known, Rigil Kent.
NGC 6025 appears as an unresolved hazy patch of light to the naked eye. With binoculars the brightest few stars are resolvable, superimposed on a background mist that enhances the view. Although the cluster lies at the edge of the rich Milky Way, it's contains enough bright stars to stand out. Through a small 80mm (3.1-inch) scope it appears X shaped, with two notably bright stars of 7th and 8th magnitude and another dozen stars brighter than 10th magnitude visible. A 200mm (8-inch) scope shows roughly 40 stars spread across 12 arc minutes.
For owners of very large amateur scopes, there are a number of faint galaxies close to NGC 6025. None are above 15th magnitude, but the brightest of which can be glimpsed with scopes of the order of 350mm (14-inch) aperture.
NGC 6025 is number 95 in the Caldwell catalogue.
NGC 6025 Data Table
|Object Type||Open Cluster|
|RA (J2000)||16h 03m 17s|
|DEC (J2000)||-60d 25m 54s|
|Apparent Size (arc mins)||12|
|Age (years)||80 Million|
|Number of Stars||80|
|Other Names||Collinder 296, Melotte 139|