|Right Ascension||00 : 44.5 (h:m)
|Declination||+85 : 20 (deg:m)
|Visual Brightness||8.1 (mag)
|Apparent Dimension||14 (arc min)|
Discovered by John Herschel between 1825 and 1833.
Perhaps the oldest known open star cluster in our Galaxy, with a calculated age of over 5 billion years (Alan Sandage's first estimate was even an age as high as 24 billion years, while Burnham claims 10-12 billion). It consists of about 120 stars, the hottest main sequence star of spectral type F2, the 10 brightest stars being yellow giants of spectral types G8 to K4 and luminosity class III, apparent magnitudes of about 12-14, corresponding to absolute magnitudes of 0 to +2.
The image in this page was obtained by Martin C. Germano.
Caldwell 1 in Patrick Moore's list, which is sorted by declination. As its Caldwell number indicates, NGC 188 is situated very close to the North celestial pole.
Last Modification: 29 Mar 1998, 13:15 MET