The week of March 14-20 takes us from lunar Day 7 through Day 11. Monday and Tuesday are the very best times to observe the Moon. There is a half Moon in the sky, it is lunar sunrise, and all the craters and mountains throw off long lovely shadows that set them off in astonishing detail! If you’ve never seen the Moon through a telescope, this will be a jaw-dropping experience!
This week, we will highlight the craters Aristillus and Autolycus.
Observe Aristillus, Complex Crater on the Moon
Aristillus/Autolycus: [NE/F10] Aristillus is a well-defined complex crater, 34 miles in diameter, with a substantial ejecta blanket, terraces, and a central collection of mountain peaks. How many can you count? An examination of the floors of Aristillus and its close neighbor to the south, Autolycus, will indicate that they formed after the lava flows that filled the Imbrium basin. If you are favored by good lighting, immediately to the north of Aristillus you will be able to make out the outlines of an unnamed ghost crater which was almost entirely submerged beneath the lava flows. Notice how ejected material from the Aristillus impact covers the southern portion of this spectral image. Can you make out an unusual dark band that travels up the northeast inner slope and disappears over the rim? When we get closer to Full Moon you will notice that Aristillus is at the center of a ray system (which means that it is less than a billion years old–a mere youngster in lunar terms!).
OF ADDITIONAL INTEREST ON LUNAR DAY 7-11:
On Monday evening, there will be several exciting events taking place on Jupiter that you can observe through small telescopes. Jupiter’s moon Europa will begin a transit across Jupiter’s face at 9:28 PM EDT. Then Europa’s shadow will begin a transit at 9:46 EDT (this is essentially a solar eclipse on Jupiter). Then at 10:13 PM EDT Io will begin a transit, followed by its shadow at 10:22
As you watch Europa approach Jupiter, consider that you are looking at one of the most likely places in the Solar System where we will find extraterrestrial life (albeit pretty small). Europa is covered with oceans of water that are 90 miles deep! (Compare our deepest oceans which are only five miles deep.) Only the top mile or so is solid ice, the rest is liquid H2O because of the many undersea volcanoes.
If you haven’t downloaded the SkySafari app from iTunes yet, now is a good time to do so. Set it up for March 14th for whatever time in your zone corresponds to 9:28 PM EDT, do a search for Jupiter, click on “center,” then zoom in until Jupiter almost fills the screen. The detail is astonishing! Not only can you clearly see the cloud bands with their munutia of details, if you click on “Time”, choose “minutes” and put it on fast forward, you can observe all four transits move across Jupiter’s face on your iPhone screen!
It is highly recommended that you get a copy of Sky and Telescope’s Field Map of the Moon, the very finest Moon map available for use at the telescope. It is available for $10.95 at www.skyandtelescope.com and on Amazon. All features mentioned in this blog will be keyed to the grid on the Field Map and will look like this: Plato: [NW/D9]
Courtesy of Gray Photography of Corpus Christi, Texas
Lunar photos: NASA / USGS / BMDO / LROC / ASU / DLR / LOLA / Moon Globe. Used by permission