What’s Up this Week: January 29 – February 4, 2007

Article written: 30 Jan , 2007
Updated: 31 Jul , 2007
by

Sinus Iridum. Credit: Greg KonkelMonday, January 29 – Tonight we will return again to the lunar surface to have a look through binoculars or telescopes at another tremendous impact region.

The Sinus Iridium is one of the most fascinating and calming areas on the Moon. At around 241 kilometers in diameter and ringed by the Juras Mountains, it’s known by the quiet name of the Bay of Rainbows, but was formed by a cataclysm. Science speculates that a minor planet around 201 kilometers in diameter once impacted our forming Moon with a glancing strike and the result of that impact caused “wavesâ€? of material to wash up to a “shorelineâ€? forming this delightful C-shaped lunar feature.

The impression of looking at an earthly bay is stunning as the smooth inner sands show soft waves called “rilles,â€? broken only by a few small impact craters. The picture is complete as Promontoriums Heraclides and LaPlace tower above the surface, at 1800 meters and 3000 meters respectively, and appear as distant “lighthousesâ€? set on either tip of Sinus Iridum’s opening.

Enjoy this serene feature tonight… It’s a lunar club challenge!

Tuesday, January 30 – Tonight we’ll head further north as we explore another challenge region – Sinus Roris.

“The Bay of Dewâ€? is actually a northern extension of the vast region of the Oceanus Procellarum. Expanding around 202 kilometers wide, many lunar maps aren’t quite true to Sinus Roris’ dimensions. Its borders are not exactly clear given the curvature on which we see this feature, but we do know the eastern edges join Mare Frigoris. You will note as you view the area that it is much lighter than most features of this type. If you seek answers, then look further north as Roris’ high albedo can be attributed to the ejecta of many impacts in this area.

It holds a fanciful place in history as we take a look at an excerpt from “Man on the Moonâ€? by Wernher van Braun:

There’s one section of the moon that meets all our requirements, and unless something better turns up on closer inspection, that’s where we’ll land. It’s an area called Sinus Roris, or “Dewy Bay,â€? on the northern branch of a plain known as Oceanus Procellarum, or “Stormy Oceanâ€? (so called by early astronomers who thought the moon’s plains were great seas.) Dr. Fred L. Whipple, chairman of Harvard University’s astronomy department, says Sinus Roris is ideal for our purpose – about 650 miles from the lunar North Pole, where the daytime temperature averages a reasonably pleasant 40 degrees and the terrain is flat enough to land on, yet irregular enough to hide in.

Journey there tonight… And look for the “Man in the Moon!â€?

Wednesday, January 31 – Today in 1961, Mercury Redstone 2 launched, carrying Ham the chimpanzee into a suborbital flight and to fame. In 1966, Luna 9 was launched. In 1958, the first US satellite – Explorer 1 – was launched and met a milestone as it proved the Earth was surrounded by intense bands of radiation which we now refer to as the Van Allen Belts.

In 1971 Apollo 14 was headed towards the Moon – and so are we as we take a look at Mare Cognitum, “The Sea That Has Become Known.â€?

Also formed by an impact, the remains of the basin ring still exist as the bright semi-circle of the Montes Riphaeus which borders it to the northwest. Look for the very bright point of Euclid to guide you. Just to its north is the Fra Mauro formation, the landing area for Apollo 14. Now let’s talk about why exploration in this area was so important!

Named for the 80 kilometer diameter Fra Mauro crater, the highlands are an area of hills that are believed to be ejecta from the impact which formed Imbrium. This debris may have came from as deep as 161 kilometers below the surface and would help us understand the physical and chemical nature of the area below the lunar crust.

The Fra Mauro formation became more interesting to scientists when the Apollo 12 seismometer at Surveyor crater 110 miles (177 km) to the west relayed to Earth signals of monthly moonquakes believed to have originated in the Fra Mauro crater as the Moon passed through its perigee. Apollo 14 landed in the hills at the edge of the crater Fra Mauro near a newer impact region called Cone crater – around 305 meters across and 76 meters deep. Astronauts Shepard and Mitchell took samples from the crater’s outer walls and photographed the interior. We’ll return in the future to study this fascinating area, but be sure to check out how near Pollux is tonight!

In 1862, Alvan Graham Clark, Jr. was at the eyepiece and made an unusual discovery. While watching Sirius, Clark uncovered the intense star’s faint companion while testing an 18 inch refractor being built at Dearborn Observatory. The scope itself was built by Clark, his father and his brother. Imagine his excitement when it turned up the white dwarf – Sirius B! Friedrich Bessel had proposed its existence back in 1844, but this is the first time it was confirmed visually.

Why not try your own hand at turning up this difficult double star? If you have problems finding the companion, don’t worry. Back in 1948, the first test photos using the Hale 5-meter (200-inch) telescope at Mt. Palomar were being taken. Believe it or not, problems with the configuration and mounting of the mirror meant that it was almost 2 years later before the first observing run was made by a scheduled astronomer!

Thursday, February 1 – With tonight’s near full Moon, we’ll use an unmistakable feature to help guide us to interesting points on the lunar surface. Even small binoculars will reveal the outstanding presence of crater Tycho with its bright ejecta pattern splashing across the surface. Look closely at one of the brightest of the rays, for it passes over Mare Nubium – the Sea of Clouds. This exceptionally dark, irregular plain stretches out over 563 by 464 kilometers and has many features that we will explore over the year.

Look closely at the bright ray of material thrown across its dark floor from the impact that caused Tycho. It is easy to see that it is laid “overâ€? the surface of the lava flow and this is an important clue to the age of lunar features. One of these rays crosses the Apollo 17 landing site 2000 kilometers from Tycho itself and may have caused a landslide from the mountains where the astronauts sampled. This suggests that Tycho is about 100 million years old.

While this might seem like a great age, the Sea Of Clouds could be between 3 to 4 billion years old. Once upon a time, an impact formed its basin as well. Thanks to the Moon’s lack of atmosphere, the lava flow quietly filled the basin and left it as we see it tonight.

Friday, February 2 – Tonight is the Full Moon. The month of February in the northern hemisphere is usually heavy in snow in the upper regions. Native Indian tribes of the north and east most often called February’s full Moon the Full Snow Moon. Some tribes also referred to this Moon as the Full Hunger Moon. This is very understandable since the artic weather conditions in their areas made hunting very unproductive.

Tonight let’s have a look at the far away world as we return again with binoculars to identify the maria once again. Take the time to repeat the names to yourself and to study a map. One of the keys to successfully learning to identify craters is by starting with large, easily recognized features.

The second rule of observation is to look closely at everything in an area. Scan around the Moon and tell me what you see. What’s that? Yes, it is Saturn! For some parts of the world, this close appearance tonight could mean an occultation or grazing event. Congratulations for spotting it and check with IOTA for times in your area!

Saturday, February 3 – Tonight we celebrate the success of Luna 9, also known as Lunik 9. On this day in 1966, the unmanned Soviet lunar probe became the first to achieve a soft landing on the Moon’s surface and successfully transmit photographs back to Earth. The lander weighed in at 99 kg, and the four petals, which formed the spacecraft, opened outward. Within five minutes of landing, antennae sprang to life and the television cameras began broadcasting back the first panoramic images of the surface of another world, proving that a landing would not simply sink into the lunar dust. Last contact with the spacecraft occurred just before midnight on February 6, 1966.

Tonight you can view the area of the first successful landing on the Moon as you turn your scopes towards Oceanus Procellarum – the Ocean of Storms. While the area will be brightly lit and it will be difficult to pick out small features, Procellarum is the long, dark expanse that runs from lunar north to south. On its western edge, you can easily identify the dark oval of Grimaldi. About one Grimaldi-length northward and on the western shore of Procellarum is where you would find the remains of Luna 9.

While no earthly-bound telescope could ever hope to achieve resolution of mission remains, it is still a wonderful way to improve your skills and enjoy a bit of history at the same time. Did you spot Regulus nearby? This could be an occultation, so please check with IOTA!

Sunday, February 4 – Today is the birthday of Clyde Tombaugh. Born in 1906, Tombaugh was the discoverer of Pluto and it happened 24 years and two weeks after his birth.

As the Moon begins to wane, we see features in a much different light. Tonight let us return to Mare Crisium and power up with the telescope to discover some of the wonderful details that can be seen. Use the map below to help you discover these wonderful features:

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

You see? It’s just as easy as knowing where to look! Don’t despair if you are clouded out tonight and cannot go crater hunting. You will see the Moon this way many times over the coming year and there are several more great things right in that area we haven’t even identified yet. You can do it!


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