||M 30, NGC 7099, Bennett
||21 h 40 min -
23° 11' Capricornus (Cap)
||Discovered 1764 by Charles
Globular cluster Messier 30, at about 26,000 light years
distance and 90 light years across, appears to us under an angular
diameter of around 12.0 arc minutes. It is fairly dense (as its
concentration class V indicates), and a fine visual object in even small
telescopes. Its brightest red giant stars are of apparent visual
magnitude 12.1, its horizontal branch giants shine at magnitude 15.1.
The core of M 30 exhibits an extremely dense stellar population and has
undergone a collapse, similar to at least 20 other of the 150 globulars in
the Milky Way Galaxy, including M 15, M 70 and possibly M 62.
Consequently, M 30's core is very small in extension, only 7.2 arc
seconds, corresponding to a linear diameter of 0.9 light years and its
half-mass radius is 1.15 arc min (8.7 light years). Thus, half of
this cluster's mass is concentrated in a spherical volume of a radius
equal to the distance of Sirius from us, or 17.4 light years diameter.
Click here or on the image for a higher resolution
version. The field of view is 37 x 25 arcminutes with north
towards the upper left (300°).
||NRGB 50:25:25:25 min @ -20°C
; all exposures unbinned, no filter on luminance
||SBIG STL-11000 with Astronomik
Type 2 RGB filterset - selfguided
||RCOS 14.5" Ritchey-Chrétien
||MaxIm DL/CCD, Sigma Pre
Beta 11, Registar, Adobe
|Location - Date - Time
||San Esteban (Chile) - 20Aug2006 @
||Transparency 8-9/10, Seeing