The western part of Hydra, which we looked at last month, is now low in the southwest, while the eastern part of the constellation is well-placed for observing in the evening hours. The eastern part of Hydra doesn’t hold quite as many outstanding deep-sky targets as the western half of the constellation, but there are several objects here that are worth taking the time to find.
Hydra contains fewer bright galaxies than many other spring constellations. The most notable galaxy within the boundaries of the constellation is M83, often called the Southern Pinwheel. This galaxy lies 8° southeast of Gamma Hydrae, about halfway between that star and Menkent, in Centaurus. M83 is a face-on barred spiral, arguably one of the most beautiful of its kind. It is also fairly bright as spiral galaxies go. However, observing this galaxy can be challenging because it lies low in the southern sky for observers in mid-northern latitudes. You will see the most detail in M83 by looking at it when it is near the meridian, from a location with a dark southern sky. Under good observing conditions, a mid-sized or larger telescope may show the spiral arms of the galaxy.
Hydra also holds a single noteworthy globular star cluster, M68. This globular cluster is smaller and fainter than many of the bright globulars of summer, but an 8”–10” telescope should be able to resolve some of its stars, while the rest create a soft background glow. M68 lies far from any of Hydra’s stars; it is easiest to find by starting from the nearby constellation of Corvus, the Crow. Imagine a line connecting Algorab (the northeastern star in Corvus) to Kraz (the southeastern star). Continue the line half again that distance to the south-southeast to find M68.
Corvus contains a few telescopic targets of its own, the most interesting of which is a pair of interacting galaxies known as the Antennae, or NGC 4038 and 4039. A mid-sized or larger telescope at high magnification will show the Antennae as a small mottled glow that is shaped like a shrimp, comma, or the letter V. The two galaxies make up the two halves of the arc, or V. This pair gets its name from two streamers or tails of material which extend north and south from the galaxies. These streamers are very difficult to observe without a large telescope and good observing conditions. To find the Antennae, look for the star 31 Crateris a few degrees west of the middle of Corvus. The Antennae are less than 1° north of this star.
