“Lunar X” is a visual phenomenon where an X appears on the Moon’s surface. What one actually sees is the contrast between the dark interiors of the Blanchinus, La Caille and Purbach craters against their bright rims. This event is typically fleeting, for the crater walls remain in shadow for just a short while as the crater rims crest the Moon’s terminator. The X is visible for about four hours per month, but you have to be on the right part of the globe with clear skies to see it.
On October 9, 2024, the X will start to form as civil twilight ends at 6:44pm CT. Peak viewing will be 7pm-9pm, but you may still be able to pick it out until the Moon sets just after 10pm.
Lunar X doesn’t require a large telescope to view – a small telescope would work well, and a good pair of steadied binoculars are worth a try. The next chance to see it in our region is December 7, 2024, so catch a peek if you can.