Messier 71 or M71 (also designated NGC 6838) is a globular cluster in the constellation Sagitta. It has an apparent visual magnitude of 8.2 and its angular diameter is 7.2 arc-minutes. M71 lies at an estimated distance of 12,700 light years. The Equinox 2000 coordinates are RA= 19h 53.8m, Dec= +18° 47´ which makes M71 best seen during the summer. The Messier Summer Star Chart shows the position of all Messier objects visible during that season.

The image above shows the uncropped view of M71 through the Takahashi E-180 Astrograph (North is to right). A 3x enlargement of this image appears to the right.

This very loose globular cluster was discovered by J-P. de Chéseaux in 1746. According to Recio-Blanco et al.(2005), the distance of M71 is 18,330 light years and its diameter is 40 light years. Its estimated mass is 40,000 solar masses and it contains 23 variable stars.

For more information, see the Messier Catalog as well as specific entries for M71 in Wikipedia and SEDS.

Messier's Description of M71

October 4, 1780
`Nebula discovered by M. Méchain on June 28, 1780, between the stars Gamma and Delta Sagittae. On October 4 following, M. Messier looked for it: its light is very faint and it contains no star; the least light makes it disappear. It is situated about 4 degrees below [south of] that which M. Messier discovered in Vulpecula. See No. 27. He reported it on the Chart of the Comet of 1779.' (diam 3.5')

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