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Home , Alphonsus (crater), Chacornac (crater), Condorcet (crater), Debes (crater), Fernelius (crater), Firmicus (crater)

Around the in 28 Days: Lunar Observing for Beginners

Course Notes

Section 20 - Lunar Day 15

Section 21 - Lunar Day 16

Section 22 - Lunar Day 17

Section 23 - Lunar Day 18

Section 24 - Lunar Day 19

Section 25 - Lunar Day 20

Section 26 - Lunar Day 21 (Last Quarter)

Copyright © 2010 Mintaka Publishing Inc. Section 20 - Lunar Day 15

Tonight we'll begin a limb-to-limb lunar history adventure by learning about the Soviet probe, Lunik 9. In 1966, the unmanned lunar traveler became the first to achieve a soft landing on the Moon’s surface and successfully transmit photographs to . The lander weighed in at 99 kg, and had four outward opening antenna petals. Within five minutes of touchdown on January 31, the antennae sprang to life and the on-board television cameras began broadcasting the first panoramic images of the surface of another world – thus proving a lander would not simply sink into the lunar dust. Last contact with the spacecraft occurred just before midnight on February 6, 1966. If you'd like to see where Lunik 9’s remains stand, turn your binoculars or telescopes towards the western lunar limb for . On its western edge, you can easily identify the dark oval of crater Grimaldi. About one Grimaldi- length northward and on the western shore of Procellarum is where you will find Lunik 9’s resting place.

Figure 20-1: The major features of the eastern part of the Moon on Day 15

Around the Moon in 28 Days: Lunar Observing for Beginners

Figure 20-2: Image from the Luna 9 lander in February, 1966 in the Oceanus Procellarum

Now let's go for the opposite limb to check out the eastern edge of in a different relief. The bright point on the shoreline is Promontorium Agarum with shallow crater to its east. Look along the shore of the mare for a southern mountain known as Mons Usov just west of Condorcet. At its northern edge that Luna 24 landed. This mission was the last of the Soviet Luna spacecraft and the third to successfully retrieve and return. It carried back 170 grams of lunar samples to the Earth on August 22 1976. For over thirty years, Luna 24 held the distinction of being the final spacecraft from any country to have landed on the Moon, only to have that record broken by Chandrayaan-1 in 2008. However, the record still holds for "soft landings"! Luna 24 also had the distinction as the last spacecraft to retrieve extra-terrestrial samples until Stardust returned in 2006. Just south of Lunik 24's final resting place is the silent Luna 23, which touched down on November 6, 1974. While it was intended to take deep core samples and return to Earth, the mission partially failed. However, it still successfully transmitted back three days of data. Directly to its west are the remains of Luna 15. It wasn't quite so lucky, though... it smashed into the surface on July 21, 1969, just a day after and walked on the Moon’s surface Unfortunate? Hardly. It began the revolutionary age of creating good relations between the Soviet Space Agency and NASA, since each agency had to share flight plans!

Around the Moon in 28 Days: Lunar Observing for Beginners

Figure 20-3: A rendering of Luna (or Lunik) 24 (courtesy of NASA)

Are you ready to see a crater that few ever get to see? Then look along the edge of the east limb and slightly south of central to identify crater Humboldt. Seen on the curve, this roughly 200 km wide crater holds a wealth of geographical details. Its flat, cracked floor has central peaks and a small mountain range, as well as radial structure. If libration and steady skies are in your favor, power up and look for dark pyroclastic areas and a concentric inner crater. Look for long, shallow and on Humboldt's west wall. It's not often you'll have a chance to study this crater, and your best bet is during the early part of the waning phase.

Figure 20-4: Humboldt crater (courtesy of Damian Peach)

Around the Moon in 28 Days: Lunar Observing for Beginners Section 21 - Lunar Day 16

As the Moon begins to wane, we see features in a much different light, since the shadows are cast on the other side! Tonight our mission is to return to Mare Crisium and power up with the telescope to discover some of the outstanding details that can be seen. Use the map below to help you discover these wonderful features:

Figure 21-1: Map of the Mare Crisium Region (image courtesy of Roger Warner, annotations courtesy of Tammy Plotner)

(1) , (2) Geminus, (3) , (4) Cleomides, (5) , (6) Tralles, (7) Lacus Bonitatis, (8) , (9) Tisserand, (10) , (11) , (12) , (13) and Pierce, (14) Picard, (15) Sinus Concordiae, (16) Taruntius, (17) Lick, (18) Shapely, (19) , (20) Promontorium Agarum.

Around the Moon in 28 Days: Lunar Observing for Beginners For a telescopic challenge, continue south to identify on the southern terminator. Just beyond its east wall, look for a ridge that extends from north to south separated by darkness from Petavius. This is , a very strange, gorge-like formation that looks as if it was caused by a meteor plowing through the Moon's surface. Palitzsch's true nature wasn't known until 1954 when the incomparable Sir resolved it as a "crater chain" using the 25" Newall refractor at Cambridge University Observatory. While you’re admiring Petavius and its branching rima, keep in mind this 80-kilometer long crack is a buckle in the flow across the crater floor!

Figure 21-2: Petavius Region (courtesy of Peter Lloyd).

Around the Moon in 28 Days: Lunar Observing for Beginners Section 22 - Lunar Day 17

Tonight Mare Crisium slowly disappears into the shadows. Just northwest of its shore is the “lunar challenge” crater, Macrobius. Spanning 64 kilometers in diameter, this Class I drops below the surface to a depth of nearly 3600 meters - about the same as many of our Earthly mines. Its central peak rises back up, and at 1100 meters may be visible as a small speck inside the crater's interior. Power up and look at how steep its crater slopes are. Can you spot the smaller impact crater Macrobius O to the southeast and conjoining crater Tisserand to the east? Check out how the sunlight highlights the walls. In this particular light you can see how high and terraced they really are!

Figure 22-1: The major features of the Moon on Day 17

Around the Moon in 28 Days: Lunar Observing for Beginners Figure 22-2: Macrobius Crater (courtesy of Damian Peach)

For another great challenge, look where and meet for the conspicuous crater Taruntius. Formed in the Copernician era and perhaps only about a billion years old, this 58 kilometer wide ring is really eroded – especially considered how young it is compared to other craters.

Figure 22-3: Taruntius crater (courtesy of Damian Peach)

Around the Moon in 28 Days: Lunar Observing for Beginners One of the reasons for looking during the waning phase is because you'll stand a better chance at spotting some of the many "ghost rings" which accompany Taruntius and the unusual amounts of lava floodings to the southwest. If the lighting is right, apply high magnification in a telescope and you'll notice its floor is fractured from an upheaval and the northwest rim has been broken up by crater.

Did you notice a slightly darker area around Cameron? Good for you for being observant! Chances are this is a deposit of volcanic ash from a small vent. Can you spot the other just south of the central peak?

Now let's have some quiet time as we view an area highlighted by sunset - the Caucasus Mountains. Easily spotted in both binoculars and small telescopes, this range towers some 5182 meters above the surrounding plains - making its peaks as high as Mount Ararat. As the shadows throw the rugged terrain into bold relief, take the time to enjoy watching nightly as the terminator moves along the lunar surface. As time passes you can follow the mountain's shadows shortening and details emerging. It's a very peaceful experience.

Figure 22-4: The Caucasus Mountains (courtesy of Greg Konkel)

Around the Moon in 28 Days: Lunar Observing for Beginners Section 23 - Lunar Day 18

Tonight the Moon gives a wonderful opportunity to revisit ancient landmark crater and learn some more history. Start by identifying crater Charconac to Posidonius' southeast. It is far older than Posidonius itself and its steep northwest slopes are nearly obliterated by the larger crater's presence. Charonac is just one of those features we don't usually study - although we should. At an estimated 4 billion years old, it sprang to life in the pre-Imbrian period, and one look at its distressed floor tells of a violent life. Look for craterlet A and Rimae Chacornac inside of its 50 kilometer diameter expanse!

Figure 23-1: The major features of the Moon on Day 18

Around the Moon in 28 Days: Lunar Observing for Beginners

Figure 23-2: The craters Posidonius and Charconac (Cacornac) and region.

If you continue southward from Posidonius and Charconac along the edge of , you'll catch partially open crater Le Monnier. This ruined ring greatly resembles a smaller version of , but only measures around 60 kilometers in diameter. Far younger than anything around it, Le Monnier was formed in the Nectarian geological period. What happened to the west wall? Who knows, but we can see areas of collapse and where the lava of Mare Serenitatis once invaded. What's so special about this crater? It contains the remains of the Luna 21 mission - forever awaiting salvage in the gray sands along Le Monnier's southern edge.

Our last challenge crater for this evening lay to the southeast and shows a very prominent central peak. Piccolomini is a 85-kilometer diameter wide, standout lunar feature - mainly because it is a fairly fresh impact crater. Its walls have not yet been destroyed by later impacts and the interior is nicely terraced. Power up as much as the atmospheric steadiness will permit

Around the Moon in 28 Days: Lunar Observing for Beginners and look carefully at the northern interior wall where perhaps a rockslide has slipped towards the crater floor. While the floor itself is fairly featureless, the central peak is awesome. Rising up a minimum of two kilometers above the floor, it's even higher than the White Mountains in New Hampshire! Can you imagine standing on the crater floor and looking up?

Around the Moon in 28 Days: Lunar Observing for Beginners Section 24 - Lunar Day 19

The Moon is waning noticeably now. Its arrival comes later each night as it slips towards the Sun again...

Tonight we'll climb the Caucasus Mountains meet the shore of for ancient crater Artistoteles. We can see companion crater Mitchell's structure and how the landscape sweeps upwards to meet ' eastern wall. Between Aristoteles and southern lay the remains of several other much older, unnamed crater remains. All that is left is a few low foothills that give us a clue to their presence. Much younger Eudoxus formed during the Copernican geological time period, making it some 3 billion years younger than its surroundings. Look closely at its 70 kilometer expanse, because this lighting reveals very steep and battered slopes, held up in part by satellite crater Eudoxus B to the north and Eudoxus G and A to the northeast.

Figure 24-1: The major features of the Moon on Day 19

Around the Moon in 28 Days: Lunar Observing for Beginners

Figure 24-2: The region around Aristoteles and Eudoxus (courtesy of Peter Llloyd)

Further south you'll encounter the remains of crater - named for "Alexander the Great" - King of Macedonia. There's very little left of royalty here, though, except age. This 85 kilometer wide, triangular-shaped formation is every bit of 4 billion years old, and lava flow and erosion has taken its toll.

Let's go for even more challenging southern terminator features by locating Stofler and . With different lighting than during the waxing phases, we now find crater noticeable. Spanning some 66 kilometers wide, this broken circular formation is overlapped by Stofler and was quite probably formed during the pre-Imbrian geological period. Its satellite A crater resides to the west, but the larger crater you see to the northeast is Kaiser. Look closely and it will appear as if Fernelius' floor elevation appears to be higher than its surroundings.

To the west of Furnelius you'll spy a small triple ring smash-up which consists of northern , southern and western ... all part of the tangled mess which helps to support the Stofler formation as well. To the south of Stofler and Faraday, you'll see evidence

Around the Moon in 28 Days: Lunar Observing for Beginners of another multiple strike area – but a much larger one. This is the conglomeration of Licetus and the four-part Heraclitus. Both formed in the pre-Imbrian period. While you'll find they share common slopes and walls, there are also several areas where later impacts have crushed and destroyed original structure.

Figure 24-3: Craters around the southern terminator of the Moon(courtesy of Peter Llloyd)

Around the Moon in 28 Days: Lunar Observing for Beginners Section 25 - Lunar Day 20

Tonight it is possible to see another landing area – the site of 15. Locate Plato, which we’ve visited before (see Lunar Day 7), and look due south past the isolated Spitzbergen Mountains to the conspicuous ring of (see Lunar Day 8). Spend a few moments enjoying Archimedes' well-etched terraced walls and textured bright floor. Now look east for the twin punctuations of and the more northern . South of Aristillus, note the heart-shape of Paulus Putredinus. There you will see - very well highlighted and alone on its northeastern bank.

Figure 25-1: The major features of the Moon on Day 20

Power up to see the Mons Hadley, including a cove known as the Hadley Delta. On the plain just north of the brilliant mountain peak is where touched down. Impressive Mons

Around the Moon in 28 Days: Lunar Observing for Beginners Hadley measures about 24 by 48 kilometers at its base and reaches up an incredible 4572 meters. If this mountain was indeed caused by volcanic activity on the lunar surface, this would make it comparable to some of the very highest volcanically caused peaks on Earth, such as Mount Shasta or Mount Rainer. To its south is the secondary peak Mons Hadley Delta—the home of the Apollo 15 landing site is just a breath north of where it extends into the cove created by Palus Putredinus.

Figure 25-2: Apollo 15 landing area (courtesy of Peter Lloyd)

Are you ready to explore some more history? Then let's continue on and identify - the centermost in a line of rings. Alphonsus is a very old, Class V crater that spans 118 kilometers and drops below the surface by about 2730 meters and contains a small central peak. Although it is partially flooded by lava, Eugene Shoemaker made of study of this crater’s formation and found dark haloes on the floor. Again, this could be attributed to volcanism and Shoemaker believed them to be low-relief “maar” volcanoes, and the halos to be dark ash. Power up and look closely at the central peak, for not only did hard land just

Around the Moon in 28 Days: Lunar Observing for Beginners northeast, but this is also the only area on the Moon where an astronomer has observed a change and backed up that observation with photographic proof.

Figure 25-3: Alphonsus Crater, left, courtesy of Damian Peach, and right, from the Ranger 9 spacecraft (courtesy of NASA)

On November 2, 1958 Nikolai Kozyrev’s long and arduous study of Alphonsus was about to be rewarded. Some two years earlier Dinsmore had taken a series of photographs from the Mt. Wilson 60" reflector that showed hazy patches in this area that could not be accounted for. Night after night, Kozyrev continued to study at the Crimean Observatory—but with no success. During the process of guiding the scope for a spectrogram the unbelievable happened—a cloud of gas containing carbon molecules had been captured! Selected as the last target for the Ranger photographic mission series, Ranger delivered 5814 spectacular high-resolution images of this mysterious region before it splattered nearby. See it yourself tonight!

Around the Moon in 28 Days: Lunar Observing for Beginners Section 26 - Lunar Day 21

Tonight we start with a look at sunset over one of the most often studied and mysterious of all craters - Plato. Although we visited it at sunrise on Day 7, Class IV Plato is simply a feature that all lunar observers like to check out because of the many reports of unusual happenings in this area.

Figure 26-1: The major features of the Moon on Day 21

Over the years, mists, flashes of light, areas of brightness and darkness, and the appearance of small craters have become a part of Plato’s lore. On October 9, 1945 an observer sketched and reported “a minute, but brilliant flash of light inside the western rim. Lunar Orbiter 4 photos

Around the Moon in 28 Days: Lunar Observing for Beginners later showed where a new impact may have occurred. While Plato’s interior craterlets average between less than one and up to slightly more than two kilometers in diameter, many times they can be observed and sometimes they cannot be seen at all under almost identical lighting conditions. No matter how many times you observe this crater, it is ever changing and worthy of your attention!

Figure 26-2: The region around Plato, lower left (courtesy of Shevill Mathers)

When you are ready, take a sojourn along the south shore of . The thin, light ring you encounter will be Crater . Further south you will discover two mountain-walled plains whose exposed floors will show bright western and dark eastern walls. These twins are Wurzelbauer to the west and Gauricus to the east. Of course, one of the most impressive of all lunar features is also highlighted to the south – crater .

Within Clavius you will see a near-spiraling curve of progressively smaller craters, beginning with Rutherford, breaking the southeast wall. Steady seeing and high power will go on to reveal numerous smaller craters populating its broad floor. Be sure to check out crater Porter to the northeast echoing Rutherford. After delighting in Clavius' extraordinary interior detail, use it to locate other interesting features. Between its southwest wall and the terminator lies another major (but smaller) mountain-walled plain known as , which may be deeply

Around the Moon in 28 Days: Lunar Observing for Beginners shadowed. Return to Clavius and head about the crater's width northwest for pentagonal Longomontanus. Can you spot on the edge crater Klaproth further south?

Figure 26-3: The region around Clavius (courtesy of Peter Lloyd)

Around the Moon in 28 Days: Lunar Observing for Beginners