M67

M67 is one of the oldest known open clusters, being about 3.2 billion years old. This is quite unusual because open clusters usually get destructed much faster. It has been calculated that M67 can expect to exist as a cluster even longer, perhaps for another few billion years. At this age, M67 contains a well-developed red giant branch, while its main sequence begins with some examples of the so-called Blue Stragglers, the brightest of which is of spectral class B8 or B9 and apparent mag 10, corresponding to a luminosity of 50 times that of the Sun at the distance of M67, which is approximately 2,700 light years. M67 contains at least 500 stars, and perhaps 200 of these are white dwarfs. Another 100 cluster members are in the mid-range of the main sequence and have been studied due to their similarity to our sun.

Image taken Feb. 6, 2013 with the D-90 and the 300mm F:4.5 Nikkor lens. Exposure was 15 seconds at ISO 3200.

Image data not saved but likely was the C-14 operating at F:3.5 with the 402 camera.