Kochab Observatory
Globular Clusters

M5
Constellation -
Serpens
Mag - 7.0
25,000 LY Distance
Est. to be 13 Billion
Years Old
Imaged 6/20/2005

Discovered 1702 by Gottfried Kirch.
Its diameter is about 165 light years,
making it one of the larger globular
clusters. At its distance of 24,500 light
years, this diameter is about 23 minutes
of arc.

Discovered by Jean-Dominique Maraldi in
1746.
At a distance of about 33,600 light years,
its diameter of 18.0 arc min corresponds
to a linear extension of about 175 light
years, and its total visual brightness of
6.2 magnitudes corresponds to an
absolute magnitude of -9.17, or roughly
360,000 times that of our sun.

M15
Constellation -
Pegasus
Mag - 7.0
33,000 LY Distance
Imaged 6/19/2005

M10
Constellation -
Ophiuchus
Mag - 7.5
14,000 LY Distance
Imaged 7/1/2005

Discovered 1764 by Charles Messier.
At its distance of 14,300 light years,
this corresponds to a linear diameter of
83 light years. Its brighter core which
can be seen visually is only less than
half as large, about 35 light-years. It is
receding from us at 69 km/sec.

M53
Constellation -
Coma Berenices
Mag - 8.5
60,000 LY Distance
Imaged 6/20/2005

Discovered 1775 by Johann Elert Bode.

Globular star cluster M53 is one of the
more outlying globulars, being about
60,000 light years away from the
Galactic center, and almost the same
distance (about 58,000 light years)
from out Solar system.

Discovered by Philippe Loys de Chéseaux in 1746.
M4 is one of the nearest globular clusters in the
sky; according to newer results (here adopted
from W.E. Harris' database), its distance is
perhaps only about 7,200 light years, which may
be the smallest for a globular; the only serious
competitor is NGC 6397 in the southern
constellation Ara, yet this one seems to be very
slightly more remote now (7,500 light years). M4
can be detected by the naked eye under very
dark skies (1.3 degrees west of Antares), and is
prominent with the slightest optical aid.

M4
Constellation -
Scorpius
Mag - 5.6
7,500 LY Distance
Imaged 5/12/2006

Discovered 1777 by Johann Elert Bode.

Globular cluster M92 is one of the original
discoveries of Johann Elert Bode, who found it on
December 27, 1777. Charles Messier
independently rediscovered it and cataloged it on
March 18, 1781, the same day as he cataloged
another 8 objects, all of them Virgo Cluster
galaxies (M84-M91). It was William Herschel who
first resolved it into stars in 1783.

According to newer sources, M92 is about 26,000
light years distant, only little more than its
brighter apparent neighbor M13. From its HRD
(or CMD), it may be a bit younger than M13 as its
turnoff point is shifted to the brighter and bluer
end. A semi-recent estimate of M92's age has
given a value of about 16 billion years old.

M92
Constellation -
Hercules
Mag - 6.4
26,000 LY Distance
Imaged 5/12/2006