Indian Run Observatory - Canfield, Ohio

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Lunar-X Imaging - Dec. 24, 2009

WHAT IS THE LUNAR-X ???

The Lunar "X" is an interesting visual effect created by the outer East wall of crater Purbach the inner West wall of the crater Blanchinus that creates the form of a letter X. This can only be seen when illuminated by the Sun for a short period of time (about four hours) around the first quarter Moon. The effect is also called "The Purbach Cross" or "Werner X".

To the Right is a Flash ™ movie as the telescope saw it. North at the top, and South at the bottom. This was shot using a Phillips SPC 900-NC Webcam attached to a Meade ETX-90 Maksutov-Cassegrain Telescope. Frame rate was set at 10 F.P.S. Below the "X" is the crater Werner, which has a diameter of 70 km, or 43.5 miles. The seeing was marginal, and there was a slight hint of atmospheric haze, which resulted in slightly lower contrast.

Above: Full Lunar View with Lunar-X visible.

Above: Crater Purbach Lunar Chart and Lunar X Image.

Above are frame captures from Quicktime Movies taken with a Modified Phillips SPC900-NC Webcam and a Meade ETX 90 Maksutov-Cassegrain Telescope.

Lunar X Visibility - 2010-2011 (All times are in UT)

• 2010 Jan. 22 15:30 Eastern North America, low in daylight

• 2010 Feb. 21 5:49 Western North America, at night

• 2010 March 22 19:24 All of North America, in daylight

• 2010 April 21 8:04 Western North America, at night

• 2010 May 20 19:52 All of North America, in daylight

• 2010 June 19 7:00 Western North America, at night

• 2010 July 18 17:52 Extreme eastern North America, low in daylight

• 2010 Aug. 17 4:58 Western North America, at night

• 2010 Sept. 15 16:40 Below the horizon, in daylight

• 2010 Oct. 15 5:15 Western North America, at night

• 2010 Nov. 13 18:46 Eastern North America, in daylight

• 2011 Jan 11 23:38 All of North America (west in daylight)

• 2011 Feb. 10 14:06 Atlantic Canada, low in daylight

• 2011 March 12 4:00 All of North America

• 2011 April 10 17:01 Eastern North America, daylight