Expected New Moons and Appointed Times for 2023

Listed below are the computations for 2023 for the expected dates of New Moon visibility from Israel. The possible projected dates for the Appointed Times for 2023 are given in a second table below the New Moons table.

PLEASE NOTE: The "Date of Visibility" column dates are the dates on which the New Moon is expected to be seen--beginning at sunset of the listed day. All dates listed are to be reckoned from sunset of listed day and date through the next day at sunset in the following New Moon table.

**2023/2024 New Moon Data**
New Moon	Date of Visibility	Sunset	Moon Set	Lag Time	% of Illum.	Moon Alt.	Sun Alt.	VN	Sighted?
11th	Monday, January 23, 2023	5:05	7:00	115 min.	4.89%	20.0	-23.6	279.2	1/23/23
12th	Tuesday, February 21, 2023	5:30	6:55	85 min.	2.80 %	16.0	-18.0	199.0	2/21/23
1st	Wednesday, March 22, 2023*	5:52	6:46	54 min.	1.23 %	10.3	-11.7	119.0	3/23/23*
2nd	Friday, April 21, 2023	7:12	8:43	91 min.	2.71 %	16.9	-18.0	204.3
3rd	Saturday, May 20, 2023	7:32	8:36	64 min.	1.23 %	10.8	-11.7	126.7
4th	Monday, June 19, 2023	7:47	9:14	87 min.	2.41 %	15.0	-15.0	182.3
5th	Tuesday, July 18, 2023*	7:45	8:37	52 min.	0.99 %	8.92	-9.57	103.3
6th	Thursday, August 17, 2023	7:21	8:12	51 min.	1.59 %	9.63	-10.3	116.6
7th	Saturday, September 16, 2023	6:44	7:32	61 min.	2.35 %	9:14	-10.3	125.3
8th	Monday, October 16, 2023	6:06	7:00	54 min.	3.59 %	9.47	-11.5	153.3
9th	Wednesday, November 15, 2023*	4:40	6:05	85 min.	5.73 %	13.0	-17.4	234.3
10th	Thursday, December 15, 2023	4:36	5:55	79 min.	3.61 %	11.9	-15.5	188.0
11th	Friday, January 12, 2024	4:55	5:58	63 min.	1.98 %	10.2	-12.5	138.5
12th	Sunday, February 11, 2024	5:22	7:12	110 min.	4.33 %	20.7	-23.2	268.6
1st	Monday, March 11, 2024	5:44	7:08	84 min.	2.51 %	10.9	-12.2	125.3

* Wednesday, March 22, 2023 - The moon was obscured by overcast skies across Israel this evening, which marked it then as the start of the 30th day of Adar. The next evening, Thursday, March 23, 2023, thus began the month of Aviv and the start of the new year.

* Tuesday, July 18, 2023 - The moon may possibly not be visible until one evening later. Here are the stats for that date: On Wednesday evening, July 19, 2023, we expect a 7:44 pm sunset & 9:11 pm moon set (therefore, a lag time of 87 minutes), 3.56 % of illumination, with a lunar altitude at sunset of 16.3 degrees and a solar altitude of -15.6 at moonset. VN = 206.3

* Wednesday, November 15, 2023 - The moon may possibly be visible one evening earlier, but most likely not. Here are the stats for that date: On Tuesday evening, November 14, 2023, we expect a 4:40 pm sunset & 5:16 pm moon set (therefore, a lag time of 36 minutes), 1.77 % of illumination, with a lunar altitude at sunset of 5.53 degrees and a solar altitude of -7.13 at moonset. VN = 88.15

**2023 Appointed Times (March 23rd/24th New Year)**
Event	begins sunset of	ends sunset of
Passover (Lord's Supper) - Aviv 14	Wednesday, April 5	Thursday, April 6
Feast of Unleavens (1st day) - Aviv 15	Thursday, April 6	Friday, April 7
Elevation Sheaf Day (aka "wave sheaf")	Saturday, April 8	Sunday, April 9
Feast of Unleavens (7th day) - Aviv 21	Wednesday, April 12	Thursday, April 13
Pentecost	Saturday, May 27	Sunday, May 28
Day of Shouting (aka "Trumpets")	Saturday, September 16	Sunday, September 17
Day of Atonement	Monday, September 25	Tuesday, September 26
Feast of Tabernacles (1st day)	Saturday, September 30	Sunday, October 1
8th Day Assembly	Saturday, October 7	Sunday, October 8

Understanding the Calculations

Visibility Number (VN) is the difference between the sun and moon setting times plus 27 times the illuminated percent of the moon plus 5.5 times the altitude of the moon at sunset minus 5 times the altitude of the sun at moonset, all divided by 1.7.

If the VN is:

* less than 88 then the New Moon will not be seen
* between 88 and 100, it will probably not be seen
* between 100 and 112, it will probably be seen
* anything greater than 112, it will be seen in reasonable conditions.

EXAMPLE: The sun will set in Jerusalem at 6:37. The moon will set at 7:36. This is a 59 minute lag time (lag time = the time between sunset and moonset) -- plenty of time for the sky to darken enough after sunset for the moon to be sighted. 2.39% of the lunar surface will be illuminated. And the moon's altitude at sunset will be 11.4 degrees. The sun's altitude at moonset will be -12.6 degrees.

So using the calculations, we have 59 [lag time] + (27 x 2.39 = 64.53) [27 times illuminated percent] + (5.5 x 11.4 = 62.7) [5.5 times lunar altitude] - (5 x -12.6 = -63) [5 times sun's altitude] divided by 1.7 = 146.6

As seen above, anything over 112 should be visible (the higher the number, the greater the visibility), and we have a VN of 146.6 -- hence, New Moon!

Email: Brian Hoeck

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