The May Sky

Paul Curtin

May is the high point of galaxy season for northern observers. From Ursa Major through Canes Venatici, Coma, Virgo all the way to northern Lupus, the dark sky roils with distant galaxies and clusters of galaxies. For the most part these objects require clear, unpolluted skies and large aperture telescopes for serious observation. Do not despair, however, if your standard observing spot is less than ideal.
Those of us who regularly observe from the city, while certainly out of the running for the faintest fuzzies, consider the brighter of these objects a challenge for our star-hopping skills. Patience and the careful study of Kepple and Sanner will pay off greatly. new imaging technologies have also bought these denizens of the deep sky within range of amateurs.

We begin due east of Mizar (zeta Ursae Majoris- the middle star in the Big Dipper’s handle) were we find a compact region populated by faint galaxies. M101, near the border with Bootes, is on the edge of this group, outshining all the others. This is one of a number of outstanding face-on galaxies visible in May.

Proceeding south from the Big Dipper there are two great streams of galaxies to be explored. The westernmost stream begins with M109 near gamma Ursae Majoris, continuing through the beautiful open cluster known as Coma Berenices merging with the Virgo Cluster of Galaxies-an outstanding field of objects. Kepple and Sanner have detailed finder charts for this cluster, but note that even such an exhaustive guide cannot give details for all potential objects. In this region the problem is less locating a galaxy than identifying the plethora of fuzzies that pass through your field of view.

The less prominent eastern stream begins southeast of eta Ursae Majoris with the famed Whirlpool Galaxy, M51. Like M101, M51 presents itself face on, displaying its full spiral structure. The cascade of galaxies falls south from M51, ending in our own galactic neighborhood with two globular clusters, M3 and NGC 5466 on the Canes Venatici/Bootes border and, farther south, the globular clusters M53 and NGC 5053 near alpha Comae Berenices.

Bootes, set atop bright Arcturus, lacks the subtle deep sky objects of his western neighbors. In exchange, he displays a distinct form composed of relatively bright stars.

Southern observers can enjoy both the galaxies of Virgo as well as dip into the Milky Way in Lupus. Lupus abounds in interesting double stars as well as planetary nebulae and globular clusters. Try to locate the planetary nebula IC 4406. Due to its distinctive spiral form it can easily be mistaken for a galaxy.

The Planets in May

Mercury moves from the morning sky into evening dusk at month’s end.

Venus is a rather difficult morning object.

Mars remains prominent to the naked eye but is truly disappointing in all but the largest telescopes.

Jupiter is in Libra. It is a fine object around midnight.

Saturn, having dominated the night sky all spring, begins to slip lower in the western sky after dark.

Bibliography

Burnham, Robert Jr., Burnham's Celestial Handbook, New York: Dover, 1978.

Gupta, R. (ed.), Observers Handbook 2006. Toronto: University of Toronto Press, 2005.

Kepple, G. R., Sanner, G. W., The Night Sky Observers Guide, Richmond, Virginia: Willman-Bell, 1999.

Tirion, W., Rappaport, B., Remaklus, W., Uranometria Deep Sky Atlas, Richmond, Virginia: Willman-Bell, 2000.

Webb, T. W., Celestial Objects for Common Telescopes, New York: Dover, 1962.