M71

Messier 71 (also designated NGC 6838) is an 8.2 mag globular cluster in the constellation Sagitta, which covers an area of 6,1' x 6,1'. The classification of M71 as globular cluster has been disputed for a long time, since its condensation is rather low for its class, it might also have been a dense open star cluster. Additionally, the cluster's color-magnitude diagram indicates a relatively young age, and high metallicity, both are unusual for a globular cluster of the Milky Way. However, newer investigations of the cluster's core density suggest a categorization as a young and loose globular. Its distance has been measured to 13,000 light years.

M71 was discovered by De Chéseaux. Charles Messier cataloged it based on his observations of October 4, 1780, as a nebula without stars. It was first resolved into stars by William Herschel in 1783.

Vulpecula and Sagitta, zoom lens photograph.

Exposure Data

Instrument: Intes Micro 8" f/6 Maksutov-Newton
F/stop: 6.0
Exposure: R: 18 x 30 sec, G: 18 x 30 sec, B: 15 x 60sec
CCD: ST-402
Date: July 19, 2006 / July 21, 2006
Exposure start: 23:26 MESZ / 0:18 MESZ
Location: O2O Observatory, Mistelbach, Lower Austria
Conditions: Visual limiting magnitude 5.3 mag / 5.2 mag
Autoguider: ST-7E
Enhancement: Dark reduced, aligned and median stacked, RGB combined, contrast enhancement, color correction/enhancement, noise reduction, vignetting correction - by Howdii

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