M13,
NGC6205, or the “Great Globular Star Cluster” in Her, is the
finest cluster. Thousands points of lights can be seen if a
scope larger than 10” is used, but only a faint and hazy speck
of light with the unaided eye on a very dark night. More than
25,000 stars brighter than mag 20 have been counted in M13. Its
distance is 25,000 l-y. The impression that the stars are
“packed” in the cluster’s center is false. The density is still
not more than 1 star per cubic l-y, which is rather dense but
not ‘packed’. Still if Earth would be in the center, we would
see thousands of stars brighter than Venus, a few even as bright
as the Moon! Since no dark nights there, astronomy would not be
possible. M13 is one of the older “globs”, about 10 billion
years.
M14,
NGC6218 in
Oph, is another old cluster of stars. Its only notoriety is that
it had a rare SuperNova in 1938, which was not detected until
1967 when old photographic plates were re-examined. Only two
SuperNovae in ‘globs’ are on record.
M22,
NGC6656, in Sgr, is one of the six finest globular clusters and
also very near us at 10,000 l-y.
M24,
NGC6603, also in Sgr, is the bright one between the Lagoon and
Swan nebulae in a bright portion of the Milky Way. It is
rectangular and subtends 1 x 2 degrees; hence only a small
portion is in the picture, 1/3 x ½ degree. This one will be
revisited soon for a longer exposure.
M47,
NGC2422 in
Pup, is a bright but sparse group, only 2,000 l-y from Earth.
The bright star just right of center is the brilliant double,
Sigma-1121; stars of mag 7 and 7.5 only 7” apart, which by the
way is a separation of 4,000 AU (100 radii of Pluto’s orbit).
The double is not resolved in the picture, too bright. 2/3rd on
the line from this double to the top RH corner is a 7.8 mag
K-type giant, a really orange one. We like to take color
exposures of this one soon
IC4715
in Sgr is
located in the NE corner of the large M24 and shows some
nebulosity
IC1283
in Sgr is
located ½ degree SE of M24 and shows clearly some interesting
nebulosities
NGC6559
in Sgr and
located 10’ E of M8, the Lagoon Neb. It has a nice nebulosity in
IR with a string of stars. A color image of 6559 is on my
agenda!
