The week of December 16-22 takes us from Lunar Day 16 to Day 22. This week we will highlight an item informally referred to as the “Lunar X,” visible on Sunday night.
Lunar X: [SE/M10; L=1°E] Around 6 days 22 hours (depending on libration–you have to get this pretty exact, it’s a narrow window) as the terminator crosses the moon crater Blanchinus, the Sun will light up the mountain peaks immediately to the west of the moon crater and you will see a brilliantly lit “X” at the intersection of the rims of Blanchinus, La Caille, and Purbach. Look for it when the terminator is around 1°-2° east. Once it has formed, the image will last only for about three hours. The formation is also known as the Purbach Cross and the Werner X. (Because it is not an officially recognized object, you will not find it listed on the Field Map.)
OF ADDITIONAL INTEREST IN SPACE
On Wednesday, Mars is 1° south of the Moon.
On Sunday, the Ursid meteor shower peaks after midnight.
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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