M30 in Capricornus
Imager Temp -20C
M30 (NGC 7099) is a globular cluster in the Capricornus constellation. It was discovered by Charles Messier in 1764. M30 is at a distance of about 26,000 light-years away from Earth and is about 90 light years across.
Half of this cluster's mass is concentrated in a spherical volume of a radius equal to the distance of Sirius from us, or 17.4 light years diameter. On the other hand, its tidal radius is large: 18.34 arc minutes, corresponding to a linear radius of 139 light years.
M30 is less loved by Messier Marathoners, as it is often the last missed object of an almost-complete Messier Marathon, a tour for viewing all Messier objects in one night (which is possible near the end of March in moonless nights).
M30 is a minor Messier object and one of those that lie very low on my horizon. Not a great image, it is included for completeness.
September 18, 2009