The week of May 24-30 takes us from Lunar Day 13 to Day 20. This week we will highlight the crater Furnerius A, viewable late Thursday evening.

Furnerius A moon craterFurnerius A: [SE/N15] On Day 3 we introduced you to Furnerius A and asked you to keep an eye on its ray system throughout the lunation. Furnerius A is only 7 miles in diameter but produces a ray that extends for 1,200 miles! How is it that such a tiny crater can splash its debris over nearly half of the Moon’s surface! Tonight, the entire length of the ray should be clearly visible. (Look closely on the Field Map for the tiny arrow that points out Furnerius A, it’s easy to miss.)

On May 26th at 5:11 a.m. from Denver westward, observers will enjoy a total eclipse of the Moon.


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 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

Andrew Planck
Furnerius A: Tiny Moon Crater That Can Splash its Debris Over Nearly Half of the Moon’s Surface

Leave a Reply

Your email address will not be published. Required fields are marked *