Lunar X and V – Terminator Shadow formation Timetable

Lunar X and V
This are a famous optical features on the moon, visible through telescopes.
When the terminator or line between light and dark on the moon,
which is located in just the right place, it appears as the letter X and V
on the moon’s surface.

2021 Lunar X and V – Visibility Timetable
Nine months of 2021 when the X and V are visible. However, as stated above, Clair Obscur effects are difficult to observe on a daytime Moon, but they are also harder to observe when the Moon is very low because of atmospheric disturbances.
(Thanks to Mary McIntyre FRAS for her blog.)

Best Month
By far the best months to see the X and V will be January and March.
February, June and December
They will be visible on a rising daytime Moon and this will be a challenge for most observers.
July and September
They will be visible on a night-time Moon but only for a short time before the Moon sets.  

2021 Timetable

  • Wednesday 20th January  –  18: 00 / 6pm UT
  • Saturday 19th February  –  08:00 / 8am UT
  • Sunday 20th March  –  02:00 / 2am UT
  • Monday 19th April  –  12:00 / 12pm BST
  • Tuesday 18th May  –  00:00 / 12am BST
  • Thursday 17th June  –  11:00 /11am BST
  • Friday 16th July  –  23:00 / 11am BST
  • Tuesday 15th August  –  10:00 / 10am BST
  • Monday 13th September  –  2200 / 10am BST
  • Wednesday 13th October  –  10:00 / 10am BST
  • Thursday 11th November  –  23:00 / 11pm UT
  • Saturday 11th December  –  12:00 / 12pm UT

Back to  Astronomical Calendar  page.

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