Lunar X Explained

The Lunar X (also known as the Werner X) is a clair-obscur effect in which light and shadow creates the appearance of a letter 'X' on the rim of the Blanchinus, La Caille and Purbach craters of the Moon.^[1]

The X is visible only for a few hours before the first quarter,^{[2] [3]} slightly below the lunar terminator. Near to the X, the Lunar V is also visible, formed by Ukert crater and several other small craters.^[2]

External links

• LPOD articles:
  • Web site: Wood . Chuck . August 29, 2004 . X Marks the Spot . Lunar Photo of the Day .
  • Web site: Wood . Chuck . December 12, 2013 . X Marks the Spot . Lunar Photo of the Day .
  • Web site: Wood . Chuck . March 9, 2014 . Xquisite . Lunar Photo of the Day .
• APOD articles:
  • Lunar X.
  • Web site: Nemiroff . Robert . Bonnell . Jerry . December 10, 2016 . The Lunar X . Astronomy Photo of the Day (APOD) . - also includes the Lunar V

Notes and References

1. News: Rice. Tony. X marks the moon on Thursday night. WRAL.
2. Book: Harrington, Philip S.. Cosmic challenge : the ultimate observing list for amateurs. 2010. Cambridge University Press. Cambridge. 978-0-521-89936-9. 1999.
3. Web site: Chapman. David M.F.. The Lunar X Files: a fleeting vision near the crater Werner. Willingboro Astronomical Society.