A double star with one of the nicest colour contrasts in the sky.
Components are Mag. 5.0 and 5.1, separated by 6.3 arc seconds. Described by 19th century observer
Admiral Smyth as "apple green and cherry red" in colour.
M13! (NGC 6205)
16hr 41.7m
+36° 28'
The "Hercules Cluster" - one of the finest globulars for observers in the northern hemisphere. At
magnitude 5.9 it is visible to the naked eye from a dark site. 16.6 arc minutes in diameter. On nights
of steady seeing, try to spot the "Y" shaped dark patch on M13's south-east side.
M92 (NGC 6341)
17hr 17.1m
+43° 08'
Another bright globular cluster, almost as spectacular as M13. Mag. 6.5,
11.2 arc minutes in diameter. Stars are more compact and fainter than M13, requires more magnification
and aperture to resolve.
NGC 6210!
16hr 44.5m
+23° 49'
A bright but small planetary nebula, visible in a 60mm refractor. Look
for a small bluish disk, 16 x 20 arc seconds in diameter. Photographic magnitude is 9.3 (8 visual),
central star mag. 12.5. (110NGC)
An 11.6 magnitude smudge of light, 0.5° NE of M13's core. An Sc
spiral galaxy, inclined about 45° to our line of sight. 3.0 x 1.4 arc minutes, about 2000 times more
distant than M13.
NGC 6229
16hr 47m
+47° 32'
Another globular cluster, smaller and fainter than M13 or M92.
Magnitude 9.4, 4.5 arc minutes in diameter.
NGC 6058
16hr 04m
+40° 41'
Another planetary nebula, larger and fainter than NGC 6210. 20 x 25
arc seconds in size, magnitude 13.3 photographic.
NGC 6181
16hr 32m
+19° 50'
An Sc spiral galaxy, about 5° SSW of NGC 6210. Magnitude 11.8,
2.6 x 1.3 arc minutes in size.
NGC 6574
18hr 12m
+14° 59'
A 12th magnitude spiral galaxy of low surface brightness. Located in
a well populated star field, 1.4 x 1 arc minutes, elongated NS.
DoDz 6
16hr 45m
+38° 17'
A type IV open cluster, 2° NNW of M13 in the upper right hand corner of
the Keystone. Four 9th and one 10th magnitude stars form a nice little pattern 17 arc minutes in size.
The "Hercules Supercluster" - one of the brighter Abell galaxy clusters.
A group of 87 or so galaxies in a field 1.25° in diameter. Most are small, low contrast, mag. 13.8 and
fainter. Brightest members are NGC 6041, 6040 and 6056. About 216 M parsecs distant.
Zwicky's Triplet
16hr 15m
+45° 30'
A rather faint group of 3 galaxies, located near 14.8th mag
NGC 6241. 15th magnitude and fainter, about 0.4 arc minutes in size. Probably not visible from WCO.
