The week of July 24 – 30 takes us from the end of Day 1 through Day 7. This week we will highlight Lacus Mortis (the “Lake of Death”), viewable on Friday evening.
Lacus Mortis: [NE/E12] (the “Lake of Death”) This is a large lava-flooded crater (90 miles in diameter) just north of Mare Serenitatis which contains rilles, wrinkle ridges, faults, and a substantial internal Tycho-class crater, Bürg. At more than four billion years old, Lacus Mortis is one of the oldest impact features on the Moon. 
The principal rille, Rima Bürg, is 60 miles long and can be seen through small telescopes. Rima Bürg starts just to the west of Bürg and connects with the SW shoreline of Lacus Mortis (which the terminator almost touches Friday night, so you may have to come back Sat.). Another rille starts halfway between Bürg and the rim of the Lacus and goes straight south. In the process it changes from a generic rille to a genuine fault whose floor falls away on the western side. Can you make out where the rille ends and the fault begins? At sunrise you will see a shadow extending to the west, and at sunset (around Day 19) the face of the fault is brightly illuminated. Make a quick sketch of Lacus Mortis, then come back later and see if you can add more detail.
OF ADDITIONAL INTEREST IN SPACE DURING LUNAR DAYS 1-7:
On Friday evening the Moon will be just 3° from Jupiter, so you can catch them both in the same binocular field. And scan the constellation Scorpius with binoculars and telescope—there is a wealth of wonderful objects within these two constellations to enjoy!
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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]
Credits:
Courtesy of Gray Photography of Corpus Christi, Texas
Lunar photos: NASA / USGS / BMDO / LROC / ASU / DLR / LOLA / Moon Globe. Used by permission
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