M3, aka NGC 5272 is one of the most beautiful globular clusters in the northern hemisphere and it islocated in the constellation Canes Venatices. Superbly dark skies granted, it can be spotted with bare eye, as it shines at a 6m2. The apparent size is about 18.6 arc minutes. Discovered by Charles Messier on the 3rd of May 1746, M3 comprises more than 500.000 stars. the core region is enormously dense, making the object a serious test for both, visual and photographic observation. In a 5" apochromatic refractor the center is split in terms of resolution, whereas a usual mirror-telescope would have to be at least 10" in diameter to catch up...in visual observation.

M3 holds more than 200 variable stars (RR Lyrae type) which makes this cluster special. The very dense core measures only 1 arc minute and this is the reason why the cluster appears very bright, even though it is further away than the center of our galaxy. It takes the light 33.900 years to travell to earth.

Another very special feature on M3 was discoverd in 1953, when Mr. Alan Sandage operated the 200" Mount Palomar scope, the largest telescope in that time, and found very hot and therefor blue stars, which appear to have a special development, other than the typical main-sequence stars. These so called "Blue stragglers" can be seen in the image.

Besides the mesmerizing beauty of that cluster, you most likely have already taken note of the sheer contless little background galaxies. These are very far in the cosmological background, having nothing to do with the cluster of course, which is a memeber of our own milky way., These galaxies you see are about 1 Bio LY away and unvisible for visual observation. Only by means of a most sensitive CCD these can be detected.