M22 - Sagittarius Cluster (Globular Cluster)M22 is a magnificent
globular cluster located in the
constellation of Sagittarius and one of the best objects of its type in the night sky. With a
magnitude of +5.1, the cluster is visible to the naked eye under dark skies and also the brightest globular in the
Messier catalogue. Only the two great southern globulars,
Omega Centauri (NGC 5139) and
47 Tucanae (NGC 104) are more brilliant. Both of these are positioned far too south in the sky to have been seen by Messier. With an apparent diameter extending 32
arc minutes, M22 covers more sky than the Full Moon.The main reason why M22 appears so large and bright is because it's close at only 10,400
light-years. It was probably the first globular to have been discovered - by Abraham Ihle in 1665 - although it has been suggested that Hevelius may have seen it earlier. M22 was included in Edmund Halley's list of 6 objects published in 1715 and then catalogued by Charles Messier on June 5, 1764.
Credit Information: Home Free Star Charts
Telescope: Meade 6000 80mm APO Refractor f/6.0
Mount IOptron CEM40
Camera ZWO183MC
70 X 120 Second Exposures W/Optolong L-Pro Filter Gain 120 Offset 20
Acquisition with SharpCap
Stacked with Deep Sky Stacker
Guiding PHD2
Processed with Astra Image
Photo taken from Seven Lakes, NC Bortle 4.5 7/19/2019
Comments