There are two images of the cluster below. The first is a a color image covering only the inner part of the cluster taken with our 20-inch telescope. The second is a wide field black & white image taken thru our 80mm VERNONscope refractor.
A CCD image taken with an STL-1301E CCD camera thru our 20-inch F/8.1 telescope working at F/5. The field of view is about 20x20 arc minutes. This image only shows the inner portion of the cluster. M-4 was only 19 degrees above the horizon when this image was taken.
A CCD image taken with an Starlight Xpress MX-716 CCD camera thru our VERNONscope 80mm refractor working at F/6.25. The field of view is about 60 x 45 arc minutes.
''Cluster of very small stars: with an inferior telescope it appears more like a nebula; this cluster is situated near Antares and on the same parallel. Observed by M. de la Caille and reported in his catalogue. Reviewed 30th Jan. and Mar. 22nd 1781. Diam. 2.5 arc min.'
This cluster was discovered in 1746 by de Cheseaux. Current estimates place M-4 at a distance of 10,000 light years, with an age of 14 billion years. (But Click here for the latest news on Globular Star Cluster distances and ages!!).
George Normandin, KAS
August 19thst, 2006