Ptolemy's Cluster

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Obj Type
Date Taken:
Messier 7
Star cluster
CTIO, Chile

This test image represents another SSRO test image with SKYNET using one of their PROMPT 16"  f/12 RCOS telescopes located at CTIO (Cerro Tololo Inter-American Observatory) in Chile.

M7 is a large and brilliant group, easily detected with the naked eye. As Burnham describes it, "the cluster is seen projected on a background of numerous faint and distant Milky Way stars."

This splendid cluster was known to Ptolemy, who mentioned it about 130 AD and described it as the "nebula following the sting of Scorpius." The description may also include M6, but this is uncertain. Because of this presumable discovery, the present author [hf] has proposed the name "Ptolemy's Cluster" for M7 some years ago, a proposition which has found some acceptance meanwhile.

Processed by Rick Gilbert and Jack Harvey 

Technical Details
Exposure Time:
RGB (15 x 5 seconds for each color)
Apogee Alta U47
RCOS Carbon Truss 16 inch f/11.3 Ritchey-Chretien
Software Bisque Paramount ME
© 2019 Harvey
Used with permission, No reproduction of these images are permitted without written approval from Harvey.