(click for larger image)

 

Catalogue and alternative designations UKS1 (UK Schmidt 1)

 

Type Globular cluster
Position 17 54 27.7, -24 08 44
Constellation Sagittarius
Camera and Telescope STL6303E and 31.75 cm Ritchey Chretien
Focal Ratio F9
Exposure Details LRGB = 70:60:70:70 All binned 1x1 with Astrodon NIR filters. Red is assigned to a band peaking at about 850nm, Green peaking at about 830nm and Blue at 750nm.  The luminance is "visible blocked" with zero response shorter than 700nm.
Description UKS1 was discovered on infrared plates taken by the 48" UK Schmidt telescope.  It has the incredible visual magnitude of 17.3 but still has been glimpsed in very large Dobsonians.  It has long been called the faintest globular in the milky way but recently discovered globulars in the 2MASS survey are even fainter.  The following description is from the 2MASS image caption.

This cluster, in the Galactic bulge and near the Galactic center (l=5.1, b=0.8), is quite reddened and in a very crowded stellar field. Ortolani, Bica, & Barbuy (1997, A&AS, 126, 319) present optical photometry of the cluster and find that the extinction is nearly 11 visual magnitudes, that the distance to the cluster is 7.4 kpc (24,124 light years), and that the cluster may be metal-rich. Near-infrared photometry was previously obtained for the stars in the cluster, along with those for 19 other bulge clusters, by Minniti, Olszewski, & Rieke (1995, AJ, 110, 1686).

For a comparison with a recent VISTA infrared image of this area showing the newly discovered globular cluster VVV GL001 click here