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Clear skies in September ideal time to view Milky Way
By Dr.Wayne Wooten Special to Splash! magazine
September and October are often the clearest months of the year for Gulf Coast residents, and with the summer Milky Way spanning overhead, ideal times to enjoy our home galaxy.
If you don't live in the country, a trip to the beach, Naval Live Oaks, or some rural area with little light pollution is certainly rewarding, but you have to work these deep sky observing sessions around the natural light pollution of our satellite, the Moon, as well.
For September, the Moon will be full on September 7th, so the first week will find the Moon waxing and getting brighter and setting later each evening. If this full moon looks unusually large on the 7th, you are not wrong. The Moon will then be at perigee, about 222,000 miles from us, about as close to the Earth and large as it ever gets. So by contrast, when the moon is at apogee two weeks later and about 30,000 miles more distant, on the other side of its orbit, it will appear even smaller than the disk of the Sun, and the solar eclipse visible in the South Atlantic will be annular, with the Moon in front of the Sun, but a ring of sunlight still seen around the smaller Moon's limb.
If you can't see the Galaxy well in the first week, look instead to the west for Jupiter, the brightest object in the SW. Even small scopes will show the four planet-sized moons (all bigger than Pluto) that orbit its equator, but as the giant planet gets lower each evening, it will be hard to see the changing belts and zones and its two Red Spots (Junior is hanging in there for the moment) with scopes at 100X and up as the atmosphere is turbulent lower near the horizon. By month's end, the waxing crescent moon pass just below Jupiter on Monday, September 25, while Mercury approaches Jupiter low in the SW on the 30th; we'll write more on them in October.
By September 10, the Moon is waning and rising later each evening, giving several hours of darkness for twilight observers of the Galaxy.
While the naked eye, dark adapted by several minutes away from any bright lights, is a wonderful instrument to stare up at the Galaxy arching overhead, binocs are better for spotting specific deep sky objects all along the plane of the Galaxy.
The core of the Galaxy lies toward Scorpius and Sagittarius in the south as darkness fall, so this is the brightest part of the Galaxy.
For a nice printable free star chart, go to www.skymaps.com and print out the August and September issues for the northern hemisphere. The webmaster also includes nice calendars of notable events easily seen with the naked eye and binocs for the months in question as well.
Using this resource, let's work our way northward. In Scorpius, note the reddish color of Antares, the heart of the Scorpion. It is a red giant star, big enough to swallow up the orbit of Jupiter, but only half as hot as our Sun, hence its reddish hue. In the Scorpion's Tail are two nice binocular clusters, M-6 and M-7, both well resolved into dozens of stars with 10x50 binocs, Above and to the left of them is the teapot shape of Sagittarius, the Archer. The great Lagoon Nebula (first photo attached) is a stellar nursery that comes out the pour spout of the teapot like a cloud of steam, and just to the left of the lid is the fine globular cluster M-22, easily seen in binocs and well resolved in even small telescopes at 100X.
Overhead is the summer triangle of three bright stars, with the Milky Way running through the two eastern most members, Deneb to the north, and Altair to the south. The western member of the trio is Vega, the brightest star in the northern celestial hemisphere. Note that the Milky Way appears to split between Altair and Deneb in the "Great Rift".
We now understand there are billions of stars there as well, but they are almost totally hidden by a great cloud of dark carbon-rich dust lying only a few hundred light years ahead of us in the plane of our Galaxy. As we the solar system move through this dark region of the Galaxy's spiral arms, it is possible this dust will block some sunlight and even cool down our star a little, setting up an Ice Age to counter global warming, but alas, this will be thousands of years in the future, not soon enough to cool us down! Many clusters appear with binocs as we sweep overhead, but near the bottom of Cygnus, the northern cross, you will find M-27, the "Dumbell Nebula" (second photo attached), a funeral wreath of gas expelled by a dying giant star as it sheds its outer layers gently, while the core collapses to a white dwarf star, hotter than our Sun but only the size of Earth. What a way to go. Keep looking up!
Editors Note:
Dr. Wayne Wooten and EAAA President Ed Magowan at the club stargaze for the perseid meteor shower on Augustc 11 near Portofino. They used Ed's 9" telescope and PJC's new StellaCam II video camera, and photographed the LCD display with a typical digital camera most readers already own!
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