Timeless Shots: FROM OLD Comet Lovejoy: A Robotics: AUTOMATE DATA TO NEW SCIENCE p. 20 DARK-SKY DELIGHT p. 62 YOUR OBSERVATORY p. 64 THE ESSENTIAL GUIDE TO ASTRONOMY How the Moon’s Craters Got Their Names p. 26 Saturn’s Elusive D Ring p. 54 MAY 2015 NIGHT WATCH Help Measure Light Pollution p. 34 Atik One CCD Camera p. 70 US $5.99 CAN $6.99 05 Tiniest Lunar Feature You Can See p. 50 0 FnL1 03 0084 01 CUYrVyBNZWRpYQ9HcmVnb3J5IEtydWVn 02 ZXIAVNNmagQxMC40AjgwATEFVVBDLUEM MDc0ODA4MDIyMDc2kQ== 74808 02207 6 Display until April 27, 2015 Visit SkyandTelescope.com Download Our Free SkyWeek App Naming the Craters 26 May 2015 sky & telescope The Man Who Put the Names on the Giambattista Riccioli had a grander plan than meets the eye — and perhaps a secret agenda. One benefi t of binoculars is their Look at the Moon’s celestial eastern limb (on the big-picture view. Take the Moon. left) just south of the equator — there Riccioli named Looking at it with only 8 or 10 a modest crater for himself, giving him the eastern- power makes you focus on larger most ringside seat on his handiwork. Next to him is issues, such as why did the second- his assistant Francesco Grimaldi, who drew the map. quarter (waxing gibbous) Moon Then comes the Polish astronomer Johannes Hevelius, get the oceans with the ominous who had recently published his own Moon map, in 1647, Andrew names? And what’s that gulag of featuring a grab bag of royals, religious fi gures, scien- Livingston ancient Greek astronomers doing, tists, and explorers. Finally, on the opposite side sits shivering on the shores of the Sea of Cold? Why are the Langrenus, whose earlier (1645) map had used neutral crater names beginning with Al- so concentrated in the but head-scratchingly obscure names from Greek and south? And why was the great Galileo assigned such an Latin geographies. Riccioli left him in his own chosen insignifi cant little out-of-the-way crater that you need place on the shores of Mare Fecunditatis. There they 20× to spot it? are, the three pioneers of selenography, except it was The man to ask, the man with the plan, the man who pretty much winner-take-all for Riccioli. named all the major features on the Moon, was the Ital- What made his names such a success? Why do we ian Jesuit astronomer Giambattista Riccioli (1598–1671). use most of them today? Riccioli published his landmark Moon map in 1651, just 42 years after Galileo fi rst turned a telescope to the The Moon’s Eight Octants heavens and saw that the Moon was rough and moun- Riccioli divided the Moon into eight slices like a pizza, tainous — and 18 years after the Inquisition sentenced drawn on his map and labeled around the edges as seen him for advocating the Copernican system of the Earth on the facing page. They start in the celestial northeast and planets revolving around the Sun. Riccioli’s map of with “I Octans”: upper left on the map and on the Moon the Moon was the best one yet. Its detail and accuracy as seen with the naked eye. An odd place to start? Watch are impressive considering the small, primitive, hard-to- what happens. Working around clockwise in a histori- use telescopes of the time. cal timeline, Riccioli sprinkles the Moon with ancient And all those features on the map needed names. Greeks, followed by Romans and early Christians, then medieval scholars both Christian and Muslim, to end NAMING OF PARTS Riccioli’s Moon map, from his with a grand fi nale of his fellow moderns in VIII Octans, Almagestum Novum (1651). The subhead says, “Men neither the easternmost and last to be well revealed as the Moon live on the Moon. Nor do their souls go there.” Riccioli’s waxes to full. rebuke of those popular fancies is ironic — thanks to him the Riccioli didn’t always follow this design strictly. Some ALMAGESTUM NOVUM ALMAGESTUM Moon is full of famous men. And a few women. eras spill out of their octants, and along the southern SkyandTelescope.com May 2015 27 Naming the Craters Aristarchus Galilaei A Galilaei Galilaei Kepler Copernicus Reiner Gamma Reiner Gamma Reiner NASA / LRO (2) THE COPERNICANS Aristarchus, “the Greek Copernicus,” is placed above Galileo, Kepler, and prominent Copernicus himself. Right: Riccioli didn’t intend Galileo to end up with the tiny crater so named today. He applied the name to what’s now called Reiner Gamma: an odd, fl at, light marking, part of a streamer with unusual magnetism that may have been left by a comet’s ion tail. limb from Langrenus onward are more of Riccioli’s evidently Aristarchus of Samos (circa 310–230 BC), contemporaries — new authorities taking their seats Copernicus’s predecessor who fi rst proposed a Sun- opposite the ancients. centered solar system with the planets in the right order and the stars far away. Riccioli assigned him the bright- Hold the Latin! est marking on the Moon. After he had been ignored in Sorry, not an option. In Riccioli’s day, scientists not favor of Aristotle and Ptolemy for almost two thousand only published in Latin (Galileo was an exception) but years, Riccioli’s map brings things literally full circle — were usually known by Latinized names. Which gives Aristarchus’s neighbors to the south at the end of the the moderns on the Moon a deceptively antique fl avor. timeline are the Copernican astronomers of VIII Octans. Regiomontanus in VI Octans, for example, was born But here Riccioli, a Jesuit priest, was treading on Johannes Müller von Königsberg (“Regent’s Mount”) politically risky ground — just 18 years after Galileo had in 1436. A Johnny-come-lately by lunar standards, he been forced to denounce Copernicanism and was dealt a was the assistant of Purbachius, the crater above. After life sentence of house arrest. Elsewhere, in public, Ricci- Purbachius’s sudden death in 1461, Regiomontanus oli was quite the orthodox anti-Copernican, as displayed found himself fi nishing off his master’s update of on his book’s frontispiece (see page 31). But did he harbor Ptolemy’s Almagest. They had been in Italy, invited by secret Copernican sympathies? More on this later. the scholar Cardinal Bessarion, who’d gotten his hands III Octans, outer: Sunset Myth. Shortly after new on an Almagest in the original Greek; you’ll fi nd Bessa- Moon, when the crescent hangs in the west after sunset, rion north of Kepler (note that Riccioli often used the the legendary Greek strongmen Hercules and Atlas obsolete long s, which looks almost like an f ). Regio- stand boldly on the terminator. Hercules’s second-to- montanus ended up in Nuremberg, a scientifi c center last labor was to retrieve the Golden Apples of the Sun, where the wealthy Bernhard Walther helped him build apples that gave you immortality. Guarded by a serpent, the fi rst scientifi c printing press. Valtherus, now Walter, they grew in the Garden of the Hesperides, the Sunset is positioned just below Regiomontanus as if to support goddesses, at the western end of the world where Atlas him. Walther’s house, later bought by Albrecht Dürer, is stood holding up the heavens. Since the Hesperides were a Nuremberg landmark to this day. Atlas’s daughters, he agreed to fetch the apples if Her- cules relieved him of his burden. Note how Hercules, A Quick Tour of the Octants of mixed birth, gets the smaller crater while Atlas, the I and II Octans: Ancient Astronomers On Ice. The north 100% god with the full-time job, gets the larger. polar region glitters with ancient Greeks. Plato, Aris- III Octans (inner) and IIII: Rome. Julius Caesar earns toteles, Archimedes, and Eratosthenes are the leading his place here thanks to the Julian calendar, which lights, but who outshines them all? For Riccioli it was brought the dates back in line with the seasons for 28 May 2015 sky & telescope centuries to come. (When the calendar needed another Nectaris. Fourth-century Alexandria was the New York tune-up by 1582, Pope Gregory turned to Aloysius Lilius of its time, and Saint Theophilus was its crusading and Christopher Clavius, duly cratered in VI Octans.) bishop. His destruction of the famous temple of Serapis Manilius is next door for his epic poem Astronomica. symbolized the fi nal triumph of Christianity over pagan- Agrippa to his south wasn’t the famous martial son- ism. His nephew Saint Cyrillus followed in his footsteps in-law of Augustus, but a later Greco-Roman astrono- by banishing the Jews. mer about whom we know next to nothing except that Hypatia, above them, is the only astronomer here, Ptolemy mentioned him observing an occultation of the with a crater nearby for her father, Theon Junior. (His Pleiades in AD 92. neighboring senior namesake lived three centuries ear- IIII Octans raises the question: What’s a Sea of Crises lier.) The pagan Hypatia, a remarkable scholar, Neopla- (Mare Crisium) doing among the serene, tranquil seas tonist philosopher, and mathematician, came to a sticky of the fi rst quarter? Riccioli followed a separate scheme end thanks to Saint Cyrillus. Her gruesome death at the for naming the maria; they seem to follow contemporary hands of Cyrillus’s agents in AD 415 could be said to popular ideas about the infl uence of the Moon’s phases mark the end of the classical world. on moods and weather. New Moon, for instance, was a Saint Catherine’s martyrdom parallels Hypatia’s; she time of changes — times of crises.