Around the Moon in 28 Days: Lunar Observing for Beginners Course Notes Section 27 - Lunar Day 22 Section 28 - Lunar Day 23 Section 29 - Lunar Day 24 Section 30 - Lunar Day 25 Section 31 - Lunar Day 26 Section 32 - Lunar Day 27 Section 33 - Lunar Day 28 (The End) Copyright © 2010 Mintaka Publishing Inc. 2 Section 27 - Lunar Day 22 Tonight's late rising Moon might seem impossible to study when you have a daytime work schedule, but why not consider going to bed early and spending the early morning hours contemplating some lunar history and the peace and quiet before the day begins? Let's journey off to the lonely Riphaeus Mountains just southwest of crater Copernicus. Northeast of the range is another smooth floored area on the border of Oceanus Procellarum. It is here that Surveyor 3 landed on April 19, 1967. Figure 27-1: The major features of the Moon on Day 22 Around the Moon in 28 Days: Lunar Observing for Beginners 3 Figure 27-2: Surveyor 3 and Apollo 12 and 14 landing sites (courtesy of NASA) After bouncing three times, the probe came to rest on a smooth slope in a sub-telescopic crater. As its on-board television monitors watched, Surveyor 3 extended its mechanical arm with a "first of its kind" miniature shovel and dug to a depth of 18 inches. The view of sub-soil material and its clean-cut lines allowed scientists to conclude that the loose lunar soil could compact. Watching Surveyor 3 pound its shovel against the surface, the resulting tiny "dents" answered the crucial question. The surface of a mare would support the landing of a spacecraft and exploration by astronauts! Now return to Copernicus, and this time head north for distinguished little Class I Pytheas. Like a bright, small ring standing alone in the southern half of dark Mare Imbrium, this high contrast feature will catch the eye. Just a bit more to the north is motley Lambert. Although it is marginally larger, notice how much darker it appears. Lambert stands on a great lunar ridge winding its way up from grand Eratosthenes 420 kilometers southeast, and the ridge continues on for another 240 kilometers. As you observe, you may notice the ridge is just slightly lighter than the background. While Lambert isn't as splashy as its neighbor to the east – Timocharis - you might catch the sunlight reflecting off the hollowed-out remains of its central peak. This Around the Moon in 28 Days: Lunar Observing for Beginners 4 may be a collapsed area of a "rebound dome” - a formation created when the crater formed during a particularly nasty impact. Can you see the bright point of crater Euler to the west? Euler is roughly the same size as Lambert and Pytheas - but has a noticeably higher central peak. If the timing is right, you may be able to see the peak of Mons Vinogradov peeking above the terminator to the west. Figure 27-3: Surveyor 3 self-portrait deploying shovel (courtesy of NASA) Figure 27-4: Crater Pytheas (courtesy of Damian Peach) Around the Moon in 28 Days: Lunar Observing for Beginners 5 Section 28 - Lunar Day 23 The slender, silent Moon is once again lit with Earthshine. As we stand here in the moments before dawn, we behold the "New Moon In the Old Moon's Arms". We've almost come full circle, haven't we? There's still more to learn... Figure 28-1: The major features of the Moon on Day 23 Around the Moon in 28 Days: Lunar Observing for Beginners 6 Before daylight comes, we journey to the lunar surface in search of crater Focault. To find it, head north to the silent C-shape of Sinus Iridum and locate the punctuation of crater Bianchini in the center of the ring of Juras Mountains. Just northeast, and near the shore of south- eastern Mare Frigoris, look for a bright little circle – crater Foucault. 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 difficult objects such as double stars... or tiny craters! Figure 28-2: Craters around Sinus Iridum To the west of Sinus Iridum, you'll see another prominent crater in the highlands - Mairan. This 39-kilometer-diameter impact crater has a very dark floor which helps it stand out against the lighter background. Shadows pick up the steep walls. Power up in a telescope and take a look at its slopes where you'll discover many little craterlets dotting the terraces and steps. At Around the Moon in 28 Days: Lunar Observing for Beginners 7 first glance in binoculars, or a low power, its wide floor might seem rather plain, but if you magnify you'll find it also has a mountain peak, craterlets and hills! Further south is the very narrow sinuous rille known as the Rimae Mairan which extends for about 61 miles and helps form the shoreline of Sinus Roris. Figure 28-3: Crater Mairan (courtesy of Damian Peach) If you follow through to the south, you will encounter Mons Gruithuisen Delta, Mons Gruithuisen Gamma and crater Gruithuisen - a wonderful series of volcanoes and their namesake. Mons Gruithuisen Gamma is often called the "Topsy Turvy Bathtub". While you might not find these features particularly impressive, consider that we're looking at something only 20 kilometers wide and only 900 meters high! Can you resolve the small craterlet at the peak? Just look at all the incredible things you have learned in less than a lunar month! Figure 28-4: - Mons Gruithuisen region (courtesy of Damian Peach) Around the Moon in 28 Days: Lunar Observing for Beginners 8 Section 29 - Lunar Day 24 This morning we'll work in the south and start by identifying the long narrow ellipse of crater Schiller. Further south along the terminator, look for a line of four prominent craters. Their interiors may be black, but the southeast walls will be brilliantly illuminated. The most striking of this quartet is Zucchius which, depending on libration, may be very shadowed. To its east is Bettinus, and at power you will see central peaks in both craters. Figure 29-1: The major features of the Moon on Day 24 Around the Moon in 28 Days: Lunar Observing for Beginners 9 Further southeast is Kirchner, and to its east is the very old Wilson. Just north of Bettinus and - at an angle to Zucchius - you will see a strange, walled, V-shaped area curving back to Schiller. This odd area is one of the Moon's older surface features. An eon or two ago, this was part of a much larger structure which can be traced here and there amidst later forming craters. Since all that is now left is some hills and ridges, no one is certain if the area formed geologically or was caused by an impact. Figure 29-2: The region around Crater Schiller (courtesy of Peter Lloyd) Now let's head a bit north... In 2006, SMART 1 went into the history books as it impacted the lunar surface in Lacus Excellentiae. Launched on September 27, 2003 by ESA, it entered lunar orbit over a year later on November 13, 2004. After operating 5000 hours through 483 starts and stops, the xenon- ion engines ran out of fuel in September 2005, but not before the mission successfully completed its mapping studies. Although the craft caused a brief flash on the surface as it ended its life, it left an indelible mark on history - one almost as important as that left in 1959 Around the Moon in 28 Days: Lunar Observing for Beginners 10 by the first craft to impact the Moon, Luna 2. You'll find Lacus Excellentiae and the SMART 1 site just south of Mare Humorum and just north of Schiller. It smashed into the western shore very near a large peak! Figure 29-3: SMART One Impact Flash courtesy of NASA Around the Moon in 28 Days: Lunar Observing for Beginners 11 Section 30 - Lunar Day 25 Even though the atmosphere and growing daylight will greatly trouble any observations this morning, there is no harm in at least looking for the challenging punctuations of Cardanus and Krafft – an area also visible on Lunar Day Thirteen (as illustrated here). Figure 30-1: The major features of the Moon on Day 25 Around the Moon in 28 Days: Lunar Observing for Beginners 12 Southern Cardanus' circular formation is typical of the Upper Imbrian period and is in excess of 3 billion years old. Spanning about 51 kilometers in diameter, its high terraced walls reach up about 2300 meters. Look for shadow play to the south which will reveal how the lunar surface slopes upward, almost drift-like. If skies are steady, power up and try to resolve the challenging little bright point of Cardanus M along the interior wall. To Cardanus' north is Cantena Krafft, a 61 kilometer long crater chain whose geological timeline origins are unknown. If you follow the series of small impacts on their trajectory northwards, you'll Moon walk right into the southern wall of 53 kilometer wide crater Krafft. Stand on its rimae and look down at the floor 1250 meters below. Krafft was formed at the same time as its southern neighbor, but it's taken a much more recent and violent impact on its eastern wall in the form of Krafft C.