The September Sky

Paul Curtin

On 11 September a partial solar eclipse will be visible in South America. See Kelly for details.

Observers with dark sky viewing locations should look for the Zodiacal light in the pre-dawn sky from 21 September to the first week of October.

Cepheus has a number of open clusters worth investigating. Look for NGC 6939, 7023, 7142, and 7380. If you have very dark skies, see if you can locate the planetary nebulae NGC 7139 and 7354. South of Cepheus is the southward tumbling string of stars known as Lacerta. This constellation serves as the symbolic liminal zone for the northern Summer and Autumn skies. Its northern sector reaches
into the Summer Milky Way and, thus, contains a number of open clusters in addition to the planetary nebula IC 5217.

The pale, subtle southern region is a prelude to fall, sprinkled throughout with multiple stars but devoid of deep sky objects. Jumping over the western regions of Pegasus and Aquarius (both feature prominently in next month's column), we look at the large smiled-shaped form east of Sagittarius: Capricornus. After the seemingly endless star fields of the galactic center, this constellation can seem somewhat disappointing. Look for the fine globular clusters M30 and Pal 12. See also alpha, sigma and omicron, all fine doubles; the triples beta and pi; and rho, a very nice quadruple.

Farther to the south we see the rather faint and indistinct forms of Microscopium and Indus. There are a number of multiple stars and faint galaxies to be found, but like Octans near the south celestial pole, this region generally lacks anything in the way of deep-sky delights.

The Planets in September

Mercury: Southern Hemisphere viewers get a great view in the early morning.

Venus is visible in the early morning sky.

Mars can be found in the morning sky in Taurus.

Jupiter is still the brightest object in the evening sky.

Saturn: look for it in the early morning sky near Regulus.

Uranus: This often overlooked planet is easy to find in Aquarius. See Kelly for finder charts.

Bibliography

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

Jones, K. G. (ed.), Webb Society Deep-Sky Observers Handbook, Volume 3, Hillside, NJ: Enslow Publishers, 1980.

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