28 May 2004

The June Sky: The Return of the Milky Way

Paul Curtin

For northern observers, the next four months are dominated by the summer Milky Way and its attendant nebulae. June evenings provide a hint of what is in store throughout the summer.

We begin with Ursa Minor, the Little Bear. Follow the westernmost stars of the Big Dipper's bowl north to Polaris, the pole star. Ursa Minor is a small dipper hanging by its handle southward from Polaris.

The region surrounding Ursa Minor is occupied by Draco, the dragon. Draco begins due west of Polaris, forming a ragged line that brings it due east of the Little Dipper, then southwards towards Hercules.

Look for the 'Lozenge' that forms the head of Draco. The Lozenge is like a small mirror image of the main part of Hercules. One of the brightest planetary nebulae, NGC 6543, is located due north of the western stars of the Lozenge. Otherwise this area is notable mainly for double stars, many of which can be split with small aperture telescopes.

South of Draco we find Hercules (mentioned last month). The highlights of this constellation are its two globular clusters, M13 and M92, but there are a number of interesting double stars to the east of the keystone. Use a small telescope to sweep this region.

Continuing southward, we find the large shield shape of Ophiuchus, the Serpent Bearer, which contains a number of globular and open clusters. Look for the globular clusters M12 and M10 within the body of Ophiuchus.

Beneath Ophiucus we see the western section of Scorpius, the Scorpion. The bright red star is Antares, the rival of Mars. Just west of Antares look for M4, an impressive globular cluster. Use a wide field view to explore this area, for it contains a number of globular clusters and interesting star fields. In July we will discuss the lower half of Scorpius but you may wish to scan eastward and south of Antares to explore the leading edge of the Northern Summer Milky Way.

Southern observers can investigate a number of double stars in Lupus, the Wolf. There are also a number of open clusters in southern Lupus and southeastern Centaurus. South of Lupus one can observe the great dark clouds of the Milky Way in Norma and eastern Centaurus.

The planets this month

Mercury is just visible to southern observers in the morning twilight. After June 10 it slips slips from sight until early July.

Venus, though invisible most of the month, is the undisputed star attraction as it transits the Sun on June 8th. See recent editions of The Citizen Scientist for details.

Mars is very low in the West after sunset and will be lost in the Sun's glare by the end of the month.

Jupiter, in Leo, remains the lone observable planet by mid-month and observers can continue to follow its satellite and atmospheric details well into July.

Saturn is now lost in twilight glare and will not emerge until August.

Bibliography

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

Gupta, R. (ed.). Observers Handbook 2004. Toronto: University of Toronto Press, 2003.

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

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