Lunar X Predictions for 2024
40°N-75°W, Eastern Time Zone 

Date, 2024

358° Colongitude

Altitude/Azimuth

Cloudy Nights

January 18

5:15 am

–37° / 345°

4:05 am

February 16

7:40 pm

+66° / 236°

6:49 pm

March 17

10:22 am

–11° / 38°

10:10 am

April 15

11:08 pm

+43° / 268°

11:41 pm

May 15

11:01 am

–16° / 53°

12:13 pm

June 13

10:15 pm

+34° / 244°

11:49 pm

July 13

9:11 am

–43° / 58°

10:48 am

August 11

8:15 pm

+24° / 212°

9:31 pm

September 10

7:49 am

–65° / 65°

8:29 am

October 9

8:12 pm

+16° / 206°

8:09 pm

November 8

8:33 am

–49° / 79°

7:49 am

December 7

10:43 pm

+4° / 253°

9:36 pm

 

Note: The Lunar X is not an instantaneous phenomenon; rather, it appears and evolves over several hours, so the times above are fundamentally approximate and serve only as a guide. The ardent observer should look a little early to catch the initial visible illumination. A less-dramatic Lunar X against a fully illuminated background can still be seen at least several days later. Because of the Moon’s nominal 29.5 day synodic period (phase-to-phase), favorable dates for a given location tend to occur on alternate months (unfavorable dates for 40°N-75°W are shaded gray in this table).

The 358° colongitude value for the terminator reaching the Lunar X and making it visible (see this RASC paper) and the corresponding lunar altitude/azimuth for 40°N-75°W were determined with WinJUPOS, which is freeware linked from the WinJUPOS download page.

The Cloudy Nights comparative data, derived by a different method, was presented in this Cloudy Nights post.

 

Update, April 15, 2024: The 358° colongitude prediction for the Lunar X was 11:08 pm EDT. The Moon was observed at 8:50 pm with a 115 mm spotting scope at 35x, and no sign of the X was evident. The Moon was observed again at 11:14 pm with an 88 mm spotting scope and the X was prominent at 25 to 60x. Here's an afocal snapshot taken with the 88 mm at 60x with an iPhone 11. Not ideal photographically, but the X, as well as the V, are clearly visible...

 

Update, February 16, 2024: The Lunar X was observed in advance of an approaching snowstorm, so it was seen through increasing cloudiness. Using an 88 mm spotting scope at 25 to 60x, the Moon was initially observed at 5:40 pm EST (sunset was at 5:37 pm) and the X was plainly visible against a dark background, although the northwest (celestial, northeast lunar) arm of the X was fragmented. It was observed again at 6:10 pm, 6:51 pm and finally at 7:15 pm (astronomical twilight ended at 7:07 pm). In each case the X was seen against a dark background, but the northwest arm was filling-in more. The final  observation, made before retiring to the WAS meeting, was definitely hampered by thicker cloudiness passing in front of the Moon. So, as suggested above, looking a bit earlier than the predicted times would be a reasonable effort.

  

Daylight Saving Time for 2024 begins on March 10 and ends on November 3. The listed times are EST/EDT as appropriate for the date.

Here's a printable PDF version.

 

Joe Stieber, December 31, 2023