Seeing the Lunar X and sunrise on the Moon, Saturday, April 5, 2025

The Lunar X and V (indicated) as visible in telescopic views. Click to embiggen for a clearer view.	Western evening sky on Saturday April 5 as seen from Adelaide at 23:17 ACDST	Western evening sky on Saturday April 55 as seen from Brisbane at 22:43 AEST
Sunrise on the Moon: Moon at 20:00 ACDST, the Lunar V is just visible.	Sunrise on the Moon: Moon at 21:00 ACDST, the Lunar V is becoming visible. Some crater walls are beginning to light up	Sunrise on the Moon: Moon at 21:00 ACDST, the Lunar V is  visible. Some crater walls are lighting up and the frist hints of the Lunar X are there

The Lunar X (also known as the Werner X) and the Lunar V will be visible this Saturday as the moon reaches First Quarter. The Lunar X is a chiaroscuro effect in which strong contrasts of light and shadow create the appearance of a letter 'X' on the rim of the Lunar craters Blanchinus, La Caille and Purbach and a letter V from the rim of the crater Ukert, along with several smaller craters. 

The X and V are seen at first quarter, visible on the lunar surface for about 4 hours. However, the Moon is not always above the horizon from a given vantage point when this happens. This month is okay for Australian observers, with the Moon low to the horizon in the eastern sates, and reasonably high on the west coast.

Lunar X occurs on Saturday April 5, 12:43 UT, 23:43 AEDST,  22:43 AEST, 23:17 ACDST, 22:17 ACST, 20:43 AWST). This is later than official first Quarter which occurs at 12:45 ACDST.

This is a telescope (and maybe good binoculars) only event. For the west coast the start of the Lunar X occurs with the Moon being 25° above the horizon, central states see it at 11° above the horizon, and for the east coast at 6° above the horizon.

Upcoming Lunar X' s are shown below:

Dates and time Lunar X and V are visible. Typically visible from about 4hours from the starting time, times in colour are daylight saving times.

Date	UT	AEST	ACST	AWST
Feb 5	08:13	21:13	20:43	16:13
Apr 5	12:43	23:43	23:17	20:43
June 3	13:18	23:18	22:30	21:18
Aug 1	10:57	20:57	20:17	18:57
Sep 29	08:46	18:46	18:16	16:46
Nov 27	10:43	21:43	21:15	18:43

If you are setting up to see the Lunar X, why not start early so you can watch sunrise on the Moon? You can watch the sides of crater walls light up as hours progressStarting from nautical twilight, an hour after sunset, image the Moon through binoculars of a telescope every hour until around moon set and you can see the walls of the Lunar V light up, then the walls of the X. 

Also if you are setting up early, catch the reappearance of Iota Geminorum from occultation by the Moon.

Iota Geminorum about to be occulted by the Moon as seen from Brisbane at 19:09 AEST	Iota Geminorum emerging from behind the Moon as seen from Brisbane at 20:09 AEST

City	Disappear dark	Reappear bright
Adelaide ACDST	-	20:26
Brisbane AEST	19:09	20:09
Canberra AEDST	19:53	21:13
Hobart AEDST	19:49	21:08
Melbourne AEDST	19:44	21:08
Sydney AEDST	19:59	21:15