Lunar X and V Times - 2019
The Lunar X and V are optical effects which are visible on
the lunar surface for about 3 - 4 hours, once a month. They are caused by
sunlight illuminating the edge of craters. The X is caused by light
illuminating the rims of craters Blanchinus, La Caille and Purback. The V is
caused by light illuminating crater Ukert along with several smaller craters.
The
X and V are usually visible a few hours before First Quarter phase, however,
due to libration, the exact time of the X and V being visible is different from
month to month. As I did in previous years, I have used the NASA Scientific
Visualisation Studio Moon Phase and Libration tool for 2019 to check the start
time of the X and V. I did this by scrolling through each month close to First
Quarter Phase, hour by hour, until I could record the times of the X and V
being visible. The times I recorded are
listed below. These times are
approximate because I just scrolled through hour by hour. If you want very precise information about
the X and V start times and libration angles, please check out this very useful
post on Cloudy Nights:
https://www.cloudynights.com/topic/630098-lunar-x-start-times-2019/
https://www.cloudynights.com/topic/630098-lunar-x-start-times-2019/
Although the X and V are visible every month, they may occur
before the Moon has risen or after it has set from your location, so you will
not see them every month. Please also note that the times given are in 24 clock
and are in UT (the same as GMT) so you will need to correct for time zones and
daylight time savings changes. I have included the approximate moonrise and moonset
times from Oxfordshire, UK and a note about when the X and V are visible from
the UK.
Date
|
Start
Time of X & V
|
Moonrise
|
Moonset
|
Visible
From UK?
|
Sun 13th January
|
12:00 UT
|
11:30
|
00:10
|
Y
|
Tue 12th February
|
02:00 UT
|
10:40
|
01:30
|
N
|
Wed 13th March
|
15:00 UT
|
09:40
|
01:40
|
Y
|
Fri 12th April
|
04:00 UT /
05:00 BST |
11:00
|
03:35
|
N
|
Sat 11th May
|
16:30 UT /
17:30 BST |
11:10
|
02:55
|
Y
|
Mon 10th June
|
04:00 UT /
05:00 BST |
12:55
|
02:20
|
N
|
Tue 9th July
|
16:00 UT /
17:00 BST |
13:20
|
01:10
|
Y
|
Thur 8th August
|
04:00 UT /
05:00 BST |
15:02
|
00:26
|
N
|
Fri 6th September
|
16:00 UT /
17:00 BST |
15:15
|
23:35
|
N
|
Sun 6th October
|
04:00 UT /
05:00 BST |
15:55
|
00:00
|
N
|
Mon 4th November
|
17:00 UT
|
14:05
|
22:55
|
Y
|
Wed 4th December
|
07:00 UT
|
13:20
|
00:00
|
N
|
Please feel free to share this information with your local astronomy society, or anybody who may find it helpful.
Mary McIntyre
Update for 2020???
ReplyDeletehttps://marysastronomyblogs.blogspot.com/2019/12/lunar-x-and-v-times-for-2020.html?m=1
DeleteI shared the 2020 times back in December- link above
ReplyDeleteThank you for writing and sharing this informative article. This article contains some of the best information on this subject. I found this easy to understand and interesting to read. This is good content. You are apparently very knowledgeable in this area and I have found this to be interesting and intelligent reading. Good job. moonrise moonset
ReplyDelete