Messier 44 and some galaxies in the background
Messier 44 is a beautiful star cluster located 600 light years away in the constellation of Cancer, also known as "Beehive". Due to its brightness
of 3.1mag the star cluster is visible as a nebulous spot even with the naked eye. The apparent diameter is given with 95' - that means Messier 44
appears three times larger than the full moon. Because of the proximity to the ecliptic it happens from time to time that the moon or one of the
planets passes through the star cluster.
The age of the star cluster is estimated to be nearly 600 million years. Therefore the cluster is almost as old as the "Hyades" in the constellation
Taurus. It is assumed that both clusters formed at the same time in the same region of the Milky Way.
The brightest star in Messier 44 is "epsilon Cancri" with an apparent magnitude of 6.3mag. Converted this gives an absolute magnitude of
M=-0.1mag, which corresponds to a luminosity of 93 suns. A total of 300 stars have an apparent magnitude of 6 to 12mag, but up to 1,000
stars with a total mass of 500-600 solar masses belong to Messier 44. The most massive stars are located in the center of the cluster, the fainter
stars are rather found in the halo. Beside 5 giant stars also 11 white dwarfs were discovered. The core radius is given as 11.4 light-years, but
up to a distance of 40 light-years the stars are gravitationally bound to the cluster.
In 2012, 2 planets were found around the stars "Pr0201" and "Pr0211". The planets are "hot Jupiters" with an orbital period of 2 to 4 days.
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In my 20" telescope the star cluster appears way too large to see it in its entirety in the eyepiece. Only single sections can be observed. The field
of view is filled with many and partly very bright stars. You get a bit of an impression of what the starry sky might look like on one of the two
planets in Messier 44: probably extremely impressive. :))
Although the star cluster is of course very imposing, it is almost more fun to go hunting for galaxies that are located far behind Messier 44, spatially
speaking. A handful of galaxies can be easily observed with more than 16" aperture, and the brightest among them are accessible even with an 8"
telescope.
The easiest to observe are the two galaxies NGC 2624/25. They have a brightness of 14.5mag/15.1mag and are 195 respectively 208 million
lightyears away from Earth. At a magnification of 270x, both can be seen with indirect vision as roundish spots of light with brighter central areas.
A little more difficult is IC 2388, which is located directly in the center of Messier 44. This galaxy is only 15.7mag bright due to its great distance
of 450 million light years and requires a bit more patience.
