Our feature constellation for May is Hydra.
According to Greek legend, Hydra was a multi-headed serpent which grew new heads when they were cut off. The monster was killed by Hercules as one of his twelve labors.
Hydra is the longest and largest constellation in the night sky. It spans well over 100 degrees. May is a great month to observe the constellation as the entire length is visible for several hours after dusk. Hydra is a faint constellation. In order to see the string of stars that comprise the serpent, one needs to get away from light polluted skies. The constellation contains several good viewing objects including galaxies, globular and open clusters and even a bright planetary nebula.
M48 - A bright open cluster that shows up to 50 bright stars visually. The entire cluster is visible by naked eye under dark skies. M48 was discovered by Charles Messier in 1771, and is around 1500 light-years distant.
M68 - One of the dimmer Messier globular clusters at magnitude 9.0. M68 has the luminosity of 50,000 suns, and is about 33,000 light years away.
M83 (The Southern Pinwheel Galaxy) - A bright (mag 8.5) spiral galaxy (WikiSky image shown at left).
A trio of carbon stars, U, V and Y Hydrae - I think these deep red stars are way cool (figuratively and literally). Hydra has three fairly bright carbon stars. U Hydrae is class N2 (mag. 4.8). Y Hydrae is somewhat redder and dimmer at mag 6.8 (N3). V Hydrae is one of the reddest stars in the night sky (mag 8, class C6). V Hydrae is reported to be in the beginning stages of forming a bipolar nebula. I've found it best to observe these stars using a small aperture scope to avoid oversaturating the color.
Comet Boattini C/2007 W1 - During the first half of May, Hydra will host a moderately bright comet. Boattini should be mag. 7-ish during its trip through Hydra, and may eventually reach mag 4.5. A finder chart can be found here. On May 15, the comet should be within one degree of Y Hydrae.
NGC 3242 (Ghost of Jupiter Nebula) - This is a bright planetary nebula (mag 8.6) around 2500 light-years distant. It shows a distinct bluish hue and a spherical size approximately equal to that of Jupiter (image at right courtesy WikiSky.org).
NGC 5694 - In 1932, Clyde Tombaugh and C.O. Lampland (while working at the Lowell Observatory) were the first to resolve and recognize this magnitude 10 object as a globular cluster. This is one of the more remote globs in the Milky Way at a distance of about 100,000 light years. It has a luminosity of 120,000 suns.
April's DSO Tour of Canes Venatici is still on-line in case you didn't get a chance to do it. Click here.
