|Right Ascension||18 : 45.2 (h:m)
|Declination||-09 : 24 (deg:m)
|Visual Brightness||8.0 (mag)
|Apparent Dimension||15.0 (arc min)
Discovered by Charles Messier in 1764.
This cluster is not so impressive as its apparent neighbor, M11, and Messier even noted that it was "not distinguished in a 3.5 foot (FL) telescope and needed a better instrument".
Nevertheless, this is a tight, beautiful cluster with brightest stars of mag 11.9, spectral type B8. Burnham mentions about 25 stars visible in 6-8 inch scopes and about 70 fainter members, Mallas/Kreimer overall 90. Its diameter of 22 light-years appear as 15 arc minutes from the 5,000 light years distance. The Sky Catalogue 2000 gives a calculated age of 89 million years for this cluster.
As Kenneth Glyn Jones mentions, James Cuffey of the Kirkwood Observatory, Indiana University, reported that a striking feature of this cluster is a well-defined zone of low star density in a region of diameter 3'.1, immediately surrounding the nucleus. It is more probable that this region is obscured by dark interstellar matter than that it is a real "hole" in the stellar population.
M26 was classified as of Trumpler type II,2,r (Trumpler), I,1,m (Sky Catalog 2000), and II,3,m (Götz).
Last Modification: 9 Dec 1999, 22:58 MET