Discoverd by J.R. Hind in March 1845, NGC 6760 appeared in John Herschel's General as GC 4473 before Dreyer assigned it number 6760 in his NGC catalog. The cluster is easily visible in a 6-inch scope, sitting on the north edge of small 25' diameter circle of 8th and 9th magnitude stars. At 120x it has some granularity and a few stars visible on its north side. It's a bit better defined in a 10-inch scope, and gives the impression of a slight E-W elongation.
NGC 6760 is a quite ordinary, moderately bright Milky Way globular, with the exception that it is more metal-rich than most. In addition, two binary pulsars have been found in it. Of these two, PSR1908+00 is one of only 11 very low mass binary pulsars known in globular clusters: the pulsar itself has 1.4 solar mass, but it's companion has just 0.02 solar mass. The pulsar system also has the very short orbital period of 3.38 hours. NGC 6760 is about 24000 light-years away from the Sun, in the direction of
the inner Milky Way.
NGC 6302 rating HARD
planetary nebula in Scorpius
RA 17h 13.2m Dec -37d 06.3' (2000)
Magnitude 10.0
NGC 6302 is located four degrees west of 2.7-magnitude Lesath, also known as the Scorpion's "stinger". It sits at the northern edge of the area surrounded by the tail of Scorpius. Discovered in 1888, the planetary was first studied and described in 1907 by E.E. Barnard.
The planetary also has two popular common names: the Bug Nebula and the Butterfly Nebula. Be warned, however, that "Butterfly" is not a unique identifer; it has also been applied to at least 3 other planetaries, including M76 (also called the Little Dumbbell), NGC 2346 and M2-9.
The Bug is a high surface brightness bipolar planetary, with one of the most complex structures known in planetaries. A hint of this can be seen in larger scopes. For example, A 10-inch shows a 1.5'x0.3' nebula with a bright circular core offset to the east. The core has a conspicuous stellar nucleus in its center. The fainter nebulosity spreads east, with a slightly brighter spot in it at the east end.
The planetary's central star, a white dwarf with 0.64 solar masses, is one of the hottest stars in the galaxy, with a surface temperature exceeding 200,000 Kelvin. This suggests the star from which it formed must have been very large. The star is surrounded by a very dense equatorial disk of gas and dust, that possibly forced the star's outflows into the observed complex bipolar structure, which has features like knots and sharp-edged lobes. NGC 6302 lies about 3400 light years away.
