alactic Observer GJohn J. McCarthy Observatory Volume 8, No. 12 December 2015 A "Disturbed" Galaxy For almost two centuries a shining beacon in the southern sky, the galaxy Centaurus A is slowly revealing its dark secrets.. See page 20 for more information. The John J. McCarthy Observatory Galactic Observer New Milford High School Editorial Committee 388 Danbury Road Managing Editor New Milford, CT 06776 Bill Cloutier Phone/Voice: (860) 210-4117 Production & Design Phone/Fax: (860) 354-1595 www.mccarthyobservatory.org Allan Ostergren Website Development JJMO Staff Marc Polansky It is through their efforts that the McCarthy Observatory Technical Support has established itself as a significant educational and Bob Lambert recreational resource within the western Connecticut Dr. Parker Moreland community. Steve Allison Tom Heydenburg Steve Barone Jim Johnstone Colin Campbell Carly KleinStern Dennis Cartolano Bob Lambert Route Mike Chiarella Roger Moore Jeff Chodak Parker Moreland, PhD Bill Cloutier Allan Ostergren Doug Delisle Doris Papp Cecilia Detrich Marc Polansky Dirk Feather Joe Privitera Randy Fender Monty Robson Randy Finden Don Ross John Gebauer Gene Schilling Elaine Green Katie Shusdock Tina Hartzell Paul Woodell Amy Ziffer In This Issue UT THE INDOW ON OUR EFT ""O W Y L " ............................... 3 INTERNATIONAL SPACE STATION/IRIDIUM SATELLITES .......... 20 LOSE NCOUNTERS WITH NCELADUS C E E .............................. 6 SOLAR ACTIVITY ........................................................... 20 ETHYS EVISITED T R ......................................................... 7 COVER PHOTO .............................................................. 20 PACE ETURNS TO LIGHT S X R F ........................................... 8 EDWIN HUBBLE AT THE TELESCOPE .................................. 21 AKING THE ONG AY T L W ................................................. 8 SECOND SATURDAY STARS ............................................... 22 UTURE ARS ISSIONS F M M ................................................. 8 DEDCEMBAR GRAPHIC CALENDAR ................................... 23 MAVEN AND THE DISAPPEARING MARTIAN ATMOSPHERE ..... 10 FIRST CONSTRUCTION FLIGHT ......................................... 11 SPACESHIP EARTH .......................................................... 12 PURCHASING A TELESCOPE .............................................. 12 DECEMBER HISTORY ...................................................... 15 DECEMBER NIGHTS ....................................................... 16 SUNRISE AND SUNSET ...................................................... 16 ASTRONOMICAL AND HISTORICAL EVENTS ......................... 16 COMMONLY USED TERMS ............................................... 19 REFERENCES ON DISTANCES ............................................ 20 2 Dec 2015 http://www.mccarthyobservatory.org December Astronomy Calendar and Space Exploration Almanac http://www.mccarthyobservatory.org Dec 2015 • 3 “Out the Window on Your Left” T’S BEEN MORE than 40 years sync (approximately 28 days). The article from the Lunar Reconnais- Isince we left the last footprint on Moon has also slowed the rota- sance Orbiter (LRO). the dusty lunar surface. Sadly, as a tional rate of Earth but its effects The most striking difference in nation founded on exploration and are not as noticeable. the two sides of the Moon is the the conquest of new frontiers, we As a result of tidal locking (or absence of large lava flows or appear to have lost our will to lead synchronous rotation), the Moon maria on the far side. This may be as a space-faring nation. But, what only presents one side to Earth. It due to the overall higher crustal if the average citizen had the means wasn’t until October 1959 that we thickness of the far side (limiting to visit our only natural satellite; were able to view the far side of the magma intrusion), as measured by what would they see out the Moon for the first time when the the GRAIL gravity-measuring window of their spacecraft as they Soviet Union’s Luna 3 spacecraft space crafts. The largest mare on entered orbit around the Moon? This sent back 29 grainy photographs the far side is Mare Moscoviense column may provide some thoughts from a distance of approximately (Sea of Moscow). This relatively to ponder when planning your visit 40,000 miles in a lunar flyby. young mare lava flow fills the 130 (if only in your imagination). Nine years later, on Christmas mile (210 km) diameter inner ring In the eons since the Moon was Eve, the crew of Apollo 8 became of the ancient Moscoviense impact formed from an orbiting ring of the first humans to look down basin and spills into a portion of rocky debris, the gravitational tidal upon the crater-covered far side. the outer ring. GRAIL measure- forces of the two bodies have been Since then, a fleet of multina- ments indicate that little or no crust at work. Over time the Earth’s tidal tional spacecraft have surveyed remains at the Moscoviense impact forces have slowed the Moon’s this yet-unvisited terrain, allow- site, in contrast to other regions of rotational rate so that its orbital ing detailed maps to be produced, the far side where the crust exceeds period and rotational period are in including the mosaics in this 35 miles (60 km) in thickness. First imaged by the Soviet Union, the features on the far side acknowledge many Russian his- torical figures including Sergei Korolev, the “Chief Designer” of the Soviet space/Moon program, Konstantin Tsiolkovsky, scientist, inventor and father of Russian rocketry and space travel theory, Dimitri Mendeleev, chemist and creator of the periodic table of ele- ments, and Yuri Gagarin, Soviet pilot, cosmonaut and first human to journey to space when he orbited the Earth on a flight lasting 108 minutes in April 1961. The largest impact basin (basins are craters larger than 200 to 250 miles, or 300 to 400 km in diam- eter) on the Moon, and one of the largest in the solar system is the South Pole-Aitken basin. The im- pact excavated a crater almost 1,500 miles (2,600 km) across and more than 5 miles (8 km) deep. The aster- Far Side of the Moon LRO Mosaic oid penetrated the crust and likely the Image credit: NASA/GSFC/Arizona State University Moon’s upper mantle. Heat from the impact melted the excavated rock, 4 Dec 2015 http://www.mccarthyobservatory.org The names adopted by the In- ternational Astronomical Union for lunar features in and around the Apollo crater are unique in that they recognize living personalities (the crew of Apollo 8). The region also honors fallen U.S. astronauts (Mare Moscoviense recognize fallen Russian cosmonauts). The names of those individuals recog- nized for their accomplishment (Apollo 8) and ultimate sacrifice are color coded on the following close-up of the crater. Crew of Apollo 8 (first to circumnavigate the Moon in December 24, 1968) • Frank Borman • William A. Anders • James A. Lovell Crew of Apollo 1 (lost in fire on the pad) • Virgil I. “Gus” Grissom creating the floor of the basin. The Apollo crater measures 300 miles • Edward H. White II number of smaller craters present (500 km) across. Scientists believe • Roger B. Chaffee on its floor indicate that the basin is that areas of the excavation may one of the oldest on the Moon. have exposed the Moon’s lower Crew of the Space Shuttle A subsequent impact within mantle (based upon the iron con- Challenger (lost shortly after the confines of the basin carved tent of the impact melt as measured liftoff on January 28, 1986) out an even deeper hole. The by orbiting spacecraft). • Michael J. Smith • Dick Scobee • Ronald McNair • Ellison Onizuka • Christa McAuliffe • Gregory Jarvis • Judith Resnik Crew of the Space Shuttle Columbia (lost on reentry February 1, 2003) • Rick D. Husband • William C. McCool • Michael P. Anderson • Kalpana Chawla • David M. Brown • Laurel Clark Elevation Profile of Apollo Crater Japan Aerospace • Ilan Ramon Exploration Agency/NASA http://www.mccarthyobservatory.org Dec 2015 • 5 Apollo Crater Image credit: NASA/GSFC/Arizona State University Close Encounters with Enceladus As the Cassini mission winds down, project scientists have been vying for one last look at several high-value targets within Saturn’s mini solar system. On October 14th, Cassini flew within 1,142 miles (1,839 km) of the north pole of the icy moon Enceladus to look for evidence that the northern polar region might have been active in the past. Two weeks later, the spacecraft executed an even closer pass of the moon’s south pole. Skimming within 30 miles (49 km) of the surface, Cassini flew through the watery jets erupting from fis- sures in the ice. This allowed the spacecraft’s instruments to analyze the jet’s composition (and that of Cassini on Approach to the subsurface ocean). The last tar- Enceladus Credit: NASA/JPL- geted encounter of the mission will be on December 19th when Cassini Caltech/Space Science Institute 6 Dec 2015 http://www.mccarthyobservatory.org passes within 3,106 miles (4,999 km) of Enceladus, Scientists ex- pect to gather additional informa- tion on the heat flow from the moon’s interior and its role in pow- ering the watery jets. Tethys Revisited Enceladus isn’t the only moon of Saturn that has captured scien- tists’ imagination. Only 662 miles (1,066 km) in diameter, Tethys’ landscape is unmatched. A plan- etary scar, Odysseus Crater is al- most 250 miles (400 km) in diam- eter, nearly two-fifths of Tethys’ diameter. That the moon survived such a collision and not shatter sug- gests that the interior