What’s Up This Week? – October 18 – 24

Monday, October 18 – For naked-eye observers, enjoy the beautiful Moon and be sure to gaze upon one of the finest of stars, Vega. Facing West at just after sundown, Vega is bright enough to shine even in the city and will appear just slightly below the zenith. The name Vega means “Falling Eagle” and it is the fifth brightest star in the sky. Enjoyed in either telescopes or binoculars, Vega has a wonderful bluish appearance and a lovely halo of spectra. This magnificent star holds a place in ancient legend and blossomed in our imaginations even more recently as it became the “star” of the movie “Contact”. As the western-most point of the “Southern Triangle”, Vega holds a special appeal for those born in the year 1977. Why? Because Vega is 27 light years away, the light you see from it tonight left the year you were born!

For telescope users, the Moon gives a wonderful opportunity tonight to study ancient the crater Posidonius. Its 84 km by 98 km (52 by 61 mile) expanse is easily seen in the most modest of optical instruments and it offers a wealth of detail in its eroded walls and 1768 meter (5800 ft.) central peak. Be sure to continue on southward from Posidonius to edge of Mare Serenitatis to view the Apollo 17 landing area!

Tuesday, October 19 – The Moon will try to overtake the skies tonight, but observers will turn their backs to it as they face north and look almost directly overhead for bright star, Deneb. Visible even under urban conditions, Deneb marks the “tail” of the constellation of Cygnus and is the northernmost star of the “Summer Triangle”. Although Deneb is around 1600 light years away, it is the 19th brightest star in the sky and also one of the most luminous. Did you know that it shines about 60,000 times brighter than our own Sun?!

For moon watchers tonight, we celebrate 35 years of space exploration as the Apollo 11 landing site now becomes visible. For telescopes and binoculars the landing area will be near the terminator at the southern edge of Mare Tranquillitatus. For those of you who would like a real challenge? Try spotting small craters Armstrong, Aldrin and Collins just east of easy craters Sabine and Ritter. No scope? No problem! Look at the Moon. The dark round area you see on the north eastern limb is Mare Crisium. The dark area below that is Mare Fecundatatis… Now look mid-way on the terminator for the dark area that is Mare Tranquillitatus.

We were there…

Wednesday, October 20 – Tonight is a wonderful chance for binoculars and small telescopes to study the Moon. Craters Aristotle and Eudoxus to the north will be easily apparent, along with the Caucasus and Apennine mountain range. For those of you looking for a slight telescopic lunar challenge? Then look no further than the Valles Alpes. More commonly known as the “Alpine Valley” this deep gash cut across the northern surface will be easily visible and the lighting conditions will be just right to explore its 1.6 km to 20.9 km (1-13 mile) wide and 177 km (110 mile) long expanse.

Don’t stay up too late, though, because the Orionid Meteor Shower is about to begin!

Thursday, October 21 – Be sure to be outdoors before dawn to enjoy one of the year’s most reliable meteor showers. The offspring of Comet Halley will grace the early morning hours as they return once again as the Orionid meteor shower. This dependable shower produces an average of 10-20 meteors per hour at maximum and the best activity begins before local midnight on the 20th; it’ll become more visible as the Moon sets, and reaches its best as Orion stands high to the south at about two hours before local dawn on the 21st.

Although Comet Halley has long since departed our Solar System, the debris left from its trail still remain scattered in Earth’s orbital pattern around the Sun allowing us to predict when this meteor shower will occur. We first enter the “stream” at the beginning of October and do not leave it until the beginning of November, making your chances of “catching a falling star” even greater! These meteors are very fast, and although they are faint, it is still possible to see an occasional “fireball” that leaves a persistent trail.

For best success, try to get away from city lights. Facing South/Southeast, simply relax and enjoy the stars of the Winter Milky Way. The “radiant”, or apparent point of origin, for this shower will be near the red giant Alpha Orionis (Betelguese), but meteors may occur from any point in the sky. You will make your meteor watching experience much more comfortable if you take along a lawn chair, blanket and a thermos of your favourite beverage.

Clouded out? Don’t despair. You don’t always need your eyes or perfect weather to meteor watch. By tuning an FM radio to the lowest frequency possible that does not receive a “clear signal”, you can practice radio meteor listening! An outdoor FM antenna pointed at the zenith and connected to your receiver will increase your chances, but it’s not necessary. Simply turn up the static and listen. Those hums, whistles, beeps, bongs, and occasional snatches of signals are our own radio signals being reflected off the meteor’s ion trail!

Pretty cool, huh?

Now, enjoy your day and be sure to take out your telescopes and have a look at the Moon tonight. One of the most sought-after and unusual features will be visible to small telescopes in the southern half of the Moon near the terminator – Rupes Recta! Also known as “The Straight Wall”, this 130 km (75 mile) long, 366 meter (1200 ft.) high feature slopes upward with the steepest angle on the lunar surface at 41 degrees. It will be a challenge under these lighting conditions, but look for triple ring craters Ptolemy, Alphonsus and Arzachel to guide you. The “Straight Wall” will appear as a very thin line stretching across the edge of Mare Nubium.

Friday, October 22 – Start your weekend with some lunar exploration as crater Copernicus becomes visible to even the most modest of optical aids. Small binoculars will see Copernicus as a bright “ring” about midway along the lunar dividing line of light and dark called the “terminator”. Telescopes will reveal its 97 km (60 mile) expanse and 120 meter (1200 ft.) central peak to perfection. Copernicus holds special appeal as it’s the aftermath of a huge meteoric impact! At 3800 meters (12,600 feet) deep, its walls are around 22 km (14 miles) thick and over the next few days, the impact ray system extending from this tremendous crater will become wonderfully apparent.

Saturday, October 23 – It’s a “Moon Gazer’s” weekend as our nearest astronomical neighbor continues to light up the night sky. Even from 383,000 km (238,000 miles) away! Don’t put away your telescopes and binoculars thinking there will be nothing to view, because one of the most “romantic” features on the lunar surface will be highlighted tonight.

The Sinus Iridium is one of the most fascinating and calming areas on the Moon. At around 241 km (150 miles) in diameter and ringed by the Juras Mountains, it’s known as the quiet name of “The Bay of Rainbows” but was formed by a cataclysm. Science speculates that a minor planet around 201 km (125 miles) in diameter once impacted our forming Moon with a glancing strike and the result of that impact caused “waves” of material to wash up to a “shoreline” forming this delightful C-shaped lunar feature. The effect of looking at a bay is stunning as the smooth inner sands show soft waves called “rilles”, broken only by a few small, impact craters. The picture is complete as Promentoriums Heraclides and LaPlace tower above the surface at 1800 meters (5900 ft.) and 3000 meters (9900 feet) respectively and appear as distant “lighthouses” set on either tip of Sinus Iridum’s opening.

Sunday, October 24 – Take the time tonight to once again return to the Moon and explore with binoculars or telescopes the area to the south around another easy and delightful lunar feature, the crater Gassendi. At around 110 km (70 miles) in diameter and 2010 meters (6600 feet) deep, this ancient crater contains a triple mountain peak in its center. As one of the most “perfect circles” on the Moon, the south wall of Gassendi has been eroded by lava flows over a 48 km (30 mile) expanse and offers a great amount of details to telescopic observers on its ridge and rille covered floor.

For those observing with binoculars? Gassendi’s bright ring stands on the north shore of Mare Humorum… An area about the size of the state of Arkansas!

Writing by Tammy Plotner