Greetings, fellow SkyWatchers! It’s big. It’s bright. It’s the Moon and the impact of SMART 1! I hope some lucky observers had a chance to see the impact on September 2. For now, the Moon will continue to be our study area of choice (or not!) this week as we continue our lunar features and double star studies. Get out your telescopes, because…
Here’s what’s up!
Monday, September 4 – Tonight let’s head towards the lunar north and take another look at the Juras Mountains surrounding the lovely and peaceful “Bay of Rainbows” – Sinus Iridum. This semi-circle of tall peaks could be the remains of a gigantic crater wall. It is speculated the area may have been caused by an impact from an enormous planetoid on a low angle of approach – with the material moving like a tidal wave across the surface. While exploring the Montes Juras, look for crater Bianchini in their midst.
Tonight let’s view a double star, Eta Lyra. Just on the edge of unaided visibility, you will find it around three finger-widths due east of Vega. This wide, disparate pair of 4.5 and 8.0 magnitude stars should be resolvable in just about any scope, but is beyond the reach of binoculars.
Tuesday, September 5 – While the graceful Gassendi will try to steal the lunar show tonight, let’s have a go at Foucault instead. To find it, head north to Sinus Iridum and locate Bianchini in the Juras Mountains. Just northeast, and near the shore of south-eastern Mare Frigoris, look for a bright little ring.
Physicist Jean Foucault played an instrumental role in the creation of today’s parabolic mirrors. His “Foucault knife edge test” made it possible for opticians to test mirror curves for optical excellence during the final phases of shaping before metallization. Thanks to Foucault’s insight, we can turn our telescopes on such difficult double stars as Beta Delphini and resolve its 0.6 arc-second distant 5.0 magnitude companion. A challenge for smaller scopes is MU Cygni. This 4.5 and 6.0 magnitude pair should be resolvable in any scope that passed Foucault’s test!
Wednesday, September 6 – Today celebrates the founding of the Astronomical and Astrophysical Society of America. Started in 1899, it is now known as the American Astronomical Society.
Tonight’s lunar journey is on the south shore of Mare Humorum where we encounter the grand crater Shickard. Truly this is one huge mountain-walled plain! Shickard’s deeply stained floor is so convex that if you were to stand in the center, you could not see the crater walls.
This evening we bid farewell to the “Rival of Mars” – Antares. We know that it is a red giant and we know that it is not alone, but did you know that Antares’ true rival is brighter Betelgeuse? Photometric measurements show that more massive Betelgeuse is slightly redder than Antares. Fortunately, the “Rival” does reside along the ecliptic plane allowing us many opportunities to see it accompany other solar system objects.
Thursday, September 7 – It’s Full Moon. Many cultures refer to this one in particular as the “Corn Moon” because this time of year most corn crops are ready for harvest.
Tonight let’s harvest some bright lunar features as we trace the ray system of Tycho in the lunar south. Look for the bright points of Kepler and Aristarchus to the northwest quadrant. In the east, dazzling crater Proclus will light up the western shore of Mare Crisium. Just north of central, look for the two bright rings of Manlius and Menelaus.
For viewers in Australia, Asia, Europe and Africa, you will also have a partial lunar eclipse. Only the edge of the Moon will actually enter the umbral shadow, but even the penumbral event is very worthwhile to watch. Be sure to check the pages of “Mr. Eclipse” – Fred Espenak – for detailed times and information. Wishing you clear skies!
Friday, September 8 – Today in 1966, a legend was born as the television program Star Trek premiered. Created by Gene Roddenberry, its enduring legacy inspired several generations to an interest in space, astronomy, and technology. Its five-year mission still airs – along with numerous movie and series sequels. May Star Trek continue to “live long and prosper!”
While the Moon essentially appears to be full throughout the night, take the time to compare the western and eastern limbs. To the west, you will see the smooth arc no longer displays high contrast features. To the east you should see a broken edge now in sunset. Watch in the days ahead as many of your favorite craters begin to reveal themselves in a “different light.”
Tonight let’s visit Alya. One of the fainter stars to receive a proper name, Theta Serpens Caput is located around a hand span due east of Beta Ophiuchi. Thankfully, resolving this wide, matched magnitude pair is easier than finding it. If you have high power, self-stabilizing binoculars, this one could be real fun!
See a shooting star while out? It could belong to the Piscid meteor stream reaching a peak of around 5 meteors per hour. This branch of the Piscids is a rather unstudied, unusual, and diffuse stream that is active all month and favors southern hemisphere observers.
Saturday, September 9 – It won’t be long until the Moon lights the skies, so let’s have a look at disparate double Kappa Pegasi. It’s the westernmost star of northern Pegasus and is around a hand span due south of Sadr – the central star of the Northern Cross. At magnitude 4.3, look for a faint companion leading the orange-yellow primary across the sky. This one could be tough for small scopes – so make a challenge of it!
On this day in 1839, John Herschel froze time by making the very first glass plate photograph – and we’re glad he did. His photo was of his father William’s famous 40-foot telescope in Slough, England. The scope had not been used in decades and was disassembled shortly after the photograph was taken. Later in 1892, on this same day, Edward Emerson Barnard was busy at Lick Observatory discovering Jupiter’s innermost moon – Amalthea.
If you’re out tonight after the Moon rises, you can spot crater J. Herschel north of Sinus Iridum on the south shore of Mare Frigoris. Look for a large, shallow crater with small Horrebow caught along its southwestern edge.
For those who like “space oddities,” be sure to check out Jupiter tonight. There will be a very curious alignment of its moons!
Sunday, September 10 – Today is the birthday of James E. Keeler. Born in 1857, Keeler was a pioneer in the field of spectroscopy and astrophysics. In 1895, he noted different areas of Saturn’s rings revolve at different velocities. This proved the rings were not solid, but rather a collection of smaller particles traveling in independent orbits.
Tonight there’s only a short time before moonrise, so let’s have a look at Beta and Gamma Lyrae – the lower two stars in the “Harp.” Beta is actually a quick change variable dropping to less than half the brightness of Gamma every 12 days, but for a few days the two stars appear to be of near equal brightness. Beta is a very unusual eclipsing spectroscopic binary. Its unseen companion may be a “collapsar.”
Now head a finger-width north of Omicron Andromedae for 15 Lacertae. Just on the edge of unaided visibility, this carbon star is also a disparate double. The 5.2 magnitude variable primary will appear more red at its faintest, but its 11.0 magnitude companion is the faintest of all!
May all your journeys be at light speed… ~Tammy Plotner with Jeff Barbour.