NGC 7006 is a distant globular cluster, 135000 light-years away, in the constellation of Delphinus. The globular resides in the galactic halo region of the Milky Way, an area of space that contains relatively few clusters. Its actual size is slightly smaller than M13 - the best globular in the northern section of sky - but since it's 5 times further out, it shines at only mag. +10.6 and spans less than 3 arc minutes of apparent sky. The cluster is one of the most distant Milky Way globulars observable with backyard telescopes.
NGC 7006 was discovered by William Herschel on August 21, 1784 and is best seen during the months of July, August and September. It has a spatial diameter of 110 light-years and is estimated to contain 250,000 stars. It's listed as number 42 in the Caldwell catalogue.
Delphinus is one of the smallest constellations in the sky. It's not particularly bright but its main quadrangle shape is easy to recognise. To locate NGC 7006, imagine a line connecting stars Sualocin (α Del - mag. +3.8) and gamma Del (γ Del - mag. +3.9) and then extend it eastwards for another 3.5 degrees.
The cluster is a challenging object for small telescopes owners. Through an 80mm (3.1-inch) refractor it appears faint and almost star light with a weak nucleus and an even weaker halo. A 250mm (10-inch) scope reveals a bright compact core surrounded by hazy fuzz that's clearly non-stellar in nature. Very large scopes at high magnifications will resolve a few of the brightest individual member stars.
In literature, NGC 7006 is mentioned by inhabitants of a distance planet in the science fiction novel "Beyond the Farthest Star" by Edgar Rice Burroughs.
NGC 7006 Data Table
|Object Type||Globular Cluster|
|RA (J2000)||21h 01m 29s|
|DEC (J2000)||16d 11m 16s|
|Apparent Size (arc mins)||2.8|
|Number of Stars||250,000|