The August Sky

Paul Curtin

The Perseid meteor shower will peak this year on the 13th of the month. The new moon will allow for ideal viewing conditions.

Most of North America will see a lunar eclipse on the evening of August 28.

The Milky Way takes center stage in the north this month. East of Lyra we find the cross-shaped form of Cygnus embedded in spectacular star clouds. In dark skies one can trace the dark rift running south from Deneb (alpha Cygni) through the eastern side of Cygnus all the way to the galactic center in Sagittarius. The southernmost star of the cross is Albireo (beta Cygni). This is a beautiful double star system. Most observers should be able to locate the open cluster M39 northeast of Deneb. In dark skies we can find the North American Nebula east of Deneb, and the Veil Nebula south of epsilon Cygni.

South of Cygnus is the distinctive form of Sagitta, an arrow pointed to the east. Although Sagitta is just outside the main concentration of the Milky Way, it still contains some very nice star fields. Look for the globular cluster M71 between gamma and delta Sagittae. Using binoculars, scan west from the arrow to locate the coat hanger, also known as Brocchi’s cluster.

North of Sagitta we find Vulpecula, a scattered string of stars in the Milky Way. Starting from gamma Sagittae and scanning due north we find M27, the Dumbbell Nebula. This is perhaps not as easy to locate as M57 in Lyra but is nonetheless a fantastic planetary nebula well worth the trouble of star hopping.

Following the Milky Way south we come across Aquila. Numerous stars in this constellation, including beta, delta and mu, are multiple. This is a fine region to sweep with binoculars. There are many planetary nebulae, though they require dark skies and large telescopes to truly appreciate them.

Continuing southward we find the teapot asterism that constitutes the main body of Sagittarius. Use the stars of the teapot to locate a plethora of deep sky objects or simply sweep the sector for some of the most impressive star clouds to be seen from Earth. One can locate M8, the Lagoon Nebula without any optical aid, for it stands out in a manner similar to the Orion Nebula. To find it, start at the spout of the teapot and sweep due north. From here one can sweep in ever wider concentric, counterclockwise circles to capture an amazing variety of objects.

To the south we move away from the Milky Way and the sky becomes dark. Telescopium and Pavo contain some globular clusters but it is the faint galaxies that really hold sway. Xi Pavonis is a lovely color-contrast double.

The Planets in August

Mercury is in the early morning twilight but disappears early in the month.

Venus is in the early evening sky. A small telescope will reveal its crescent shape .

Mars is in Taurus and can be observed from midnight until dawn.

Jupiter sits north of Antares. It dominates the southern sky most of the night.

Saturn cannot be observed this month.

Neptune is in Capricornus. The next few months are fine opportunities for locating this faint planet.

Bibliography

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

Kelly, P. (ed.), Observers Handbook 2007, Toronto: University of Toronto Press, 2006.

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