The September Sky (2006)

Note: On September 7 a partial lunar eclipse will be visible in Europe, Africa, and Asia. Observers in Africa and South America will be able to observe an annular eclipse on September 22.

The summer triangle still dominates the northern sky this month, but don’t overlook the small constellations in this region as they contain some very nice objects. Delphinus is a fine area to scan with binoculars. See if you can split the double star gamma at the tip of the dolphin’s nose. NGC 7006, a small globular cluster, and NGC 6891, a compact planetary nebula, are impressive in mid-sized telescopes.

The faint box-shaped constellation Equuleus introduces a recurrent theme in the northern autumn sky: dark sky and difficult objects. A number of its stars are multiple but the most interesting part of this sector is the globular cluster M15, in western Pegasus.

Western Aquarius has a nice variety of deep-sky objects. NGC 7009, the Saturn Nebula, is a bright planetary well worth the search. M73 is a very nice open cluster in a wide-field telescope. The tiny globular cluster M72 is a very nice sight.

To the south is the large boat-shaped constellation Capricornus. The stars alpha, sigma, beta and rho are multiples with lovely color contrasts. The globular cluster M30, south-east of zeta Capricorni, and M75 (actually in eastern Sagittarius) are the only deep sky objects visible without very large telescopes. Solar system enthusiasts should take the opportunity to locate Neptune. It can be found in the area north of theta Capricorni.

The edge of spring in the southern sky is dark. Microscopium has some double stars but little else of note. Indus contains some galaxies but even these peter out as we move southward to the very dark area of Octans and the south celestial pole.



The Planets in September

Mercury enters the evening sky towards the end of the month.

Venus is very low in the morning sky, becoming lost in the glare at the end of the month.

Mars cannot be seen this month.

Jupiter is in Libra. It can still be observed in the early evening.

Saturn, in Leo, is a morning object.

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

The August Sky (2006)

Note: August is the annual host of the Perseid meteor shower which peak this year on the twelfth of the month. These are popular in the north as they come late at night during our warm season. Unfortunately, this year will be marred by a waning, but still 80% illuminated moon. Nonetheless, if you have the opportunity to stay up late, it is a Saturday night after all, see if you can catch some of the brighter Perseids.

Some readers have mentioned that their viewing sites are less than ideal for viewing all but the brightest deep-sky objects and have requested more information on interesting stars and asterisms that can be viewed even on moonlight or hazy nights. This complaint is valid, all the more so since numerically the majority of observers (including the author!) must deal with some degree of light pollution and other adverse atmospheric conditions on a regular basis. I’ll attempt to rectify this and invite rebuke should I backslide towards too much faint-fuzzism. In return, I urge urban readers to take advantage of any opportunities to observe from dark sky locations. You may be surprised what a short trip out of town makes.

No more dramatic demonstration of the preceding principle can be found than comparing the view of the Milky Way in town and in the country. Looking 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. Observation of such emission nebulae is greatly enhanced by the use of OIII filters.

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 and there a 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: 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 early in the month but disappears by the end of August.

Venus is in the morning sky, a difficult twilight object.

Mars is lost in the sun’s glare for northerners. In the south it can still be seen low in the sky after sunset.

Jupiter is in Libra. It continues to be the most observable planet this month.

Saturn slips into the morning sky this month.

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