latitude – Cosmic Reflections

Zodiacal Light 2023

Zodiacal Light 2022

Zodiacal Light 2021

Zodiacal Light 2020

Zodiacal Light 2019

In 2023, the best dates and times for observing the zodiacal light are listed in the calendar below. The sky must be very clear with little or no light pollution. The specific times listed are for Tucson, Arizona (32° 16′ N, 111° 03′ W).

Here’s a nicely-formatted printable PDF file of the zodiacal light calendar:

Zodiacal Light Calendar 2023 Download

January 2023

SUN	MON	TUE	WED	THU	FRI	SAT
1	2	3	4	5	6	7
8 Zodiacal Light 7:02 – 7:14 p.m. West	9 Zodiacal Light 7:03 – 8:03 p.m. West	10 Zodiacal Light 7:04 – 8:04 p.m. West	11 Zodiacal Light 7:04 – 8:04 p.m. West	12 Zodiacal Light 7:05 – 8:05 p.m. West	13 Zodiacal Light 7:06 – 8:06 p.m. West	14 Zodiacal Light 7:07 – 8:07 p.m. West
15 Zodiacal Light 7:07 – 8:07 p.m. West	16 Zodiacal Light 7:08 – 8:08 p.m. West	17 Zodiacal Light 7:09 – 8:09 p.m. West	18 Zodiacal Light 7:10 – 8:10 p.m. West	19 Zodiacal Light 7:11 – 8:11 p.m. West	20 Zodiacal Light 7:11 – 8:11 p.m. West	21 Zodiacal Light 7:12 – 8:12 p.m. West
22 Zodiacal Light 7:13 – 8:13 p.m. West	23	24	25	26	27	28
29	30	31

February 2023

SUN	MON	TUE	WED	THU	FRI	SAT
			1	2	3	4
5	6	7 Zodiacal Light 7:26 – 7:58 p.m. West	8 Zodiacal Light 7:27 – 8:27 p.m. West	9 Zodiacal Light 7:27 – 8:27 p.m. West	10 Zodiacal Light 7:28 – 8:28 p.m. West	11 Zodiacal Light 7:29 – 8:29 p.m. West
12 Zodiacal Light 7:30 – 8:30 p.m. West	13 Zodiacal Light 7:31 – 8:31 p.m. West	14 Zodiacal Light 7:31 – 8:31 p.m. West	15 Zodiacal Light 7:32 – 8:32 p.m. West	16 Zodiacal Light 7:33 – 8:33 p.m. West	17 Zodiacal Light 7:34 – 8:34 p.m. West	18 Zodiacal Light 7:34 – 8:34 p.m. West
19 Zodiacal Light 7:35 – 8:35 p.m. West	20 Zodiacal Light 7:36 – 8:36 p.m. West	21	22	23	24	25
26	27	28

March 2023

SUN	MON	TUE	WED	THU	FRI	SAT
			1	2	3	4
5	6	7	8	9 Zodiacal Light 7:49 – 8:43 p.m. West	10 Zodiacal Light 7:49 – 8:49 p.m. West	11 Zodiacal Light 7:50 – 8:50 p.m. West
12 Zodiacal Light 7:51 – 8:51 p.m. West	13 Zodiacal Light 7:52 – 8:52 p.m. West	14 Zodiacal Light 7:52 – 8:52 p.m. West	15 Zodiacal Light 7:53 – 8:53 p.m. West	16 Zodiacal Light 7:54 – 8:54 p.m. West	17 Zodiacal Light 7:55 – 8:55 p.m. West	18 Zodiacal Light 7:55 – 8:55 p.m. West
19 Zodiacal Light 7:56 – 8:56 p.m. West	20 Zodiacal Light 7:57 – 8:57 p.m. West	21 Zodiacal Light 7:58 – 8:58 p.m. West	22	23	24	25
26	27	28	29	30	31

April 2023

SUN	MON	TUE	WED	THU	FRI	SAT
						1
2	3	4	5	6	7 Zodiacal Light 8:12 – 8:37 p.m. West	8 Zodiacal Light 8:13 – 9:13 p.m. West
9 Zodiacal Light 8:14 – 9:14 p.m. West	10 Zodiacal Light 8:14 – 9:14 p.m. West	11 Zodiacal Light 8:15 – 9:15 p.m. West	12 Zodiacal Light 8:16 – 9:16 p.m. West	13 Zodiacal Light 8:17 – 9:17 p.m. West	14 Zodiacal Light 8:18 – 9:18 p.m. West	15 Zodiacal Light 8:19 – 9:19 p.m. West
16 Zodiacal Light 8:20 – 9:20 p.m. West	17 Zodiacal Light 8:21 – 9:21 p.m. West	18 Zodiacal Light 8:22 – 9:22 p.m. West	19 Zodiacal Light 8:23 – 9:23 p.m. West	20 Zodiacal Light 8:24 – 9:24 p.m. West	21	22
23	24	25	26	27	28	29
30

May 2023

SUN	MON	TUE	WED	THU	FRI	SAT
	1	2	3	4	5	6
7 Zodiacal Light 8:41 – 9:41 p.m. West	8 Zodiacal Light 8:42 – 9:42 p.m. West	9 Zodiacal Light 8:43 – 9:43 p.m. West	10 Zodiacal Light 8:44 – 9:44 p.m. West	11 Zodiacal Light 8:45 – 9:45 p.m. West	12 Zodiacal Light 8:46 – 9:46 p.m. West	13 Zodiacal Light 8:47 – 9:47 p.m. West
14 Zodiacal Light 8:48 – 9:48 p.m. West	15 Zodiacal Light 8:49 – 9:49 p.m. West	16 Zodiacal Light 8:50 – 9:50 p.m. West	17 Zodiacal Light 8:51 – 9:51 p.m. West	18 Zodiacal Light 8:52 – 9:52 p.m. West	19 Zodiacal Light 8:53 – 9:53 p.m. West	20 Zodiacal Light 8:54 – 9:54 p.m. West
21	22	23	24	25	26	27
28	29	30	31

June 2023

July 2023

August 2023

SUN	MON	TUE	WED	THU	FRI	SAT
		1	2	3	4	5
6	7	8	9	10	11	12
13	14 Zodiacal Light 3:59 – 4:18 a.m. East	15 Zodiacal Light 3:19 – 4:19 a.m. East	16 Zodiacal Light 3:20 – 4:20 a.m. East	17 Zodiacal Light 3:21 – 4:21 a.m. East	18 Zodiacal Light 3:22 – 4:22 a.m. East	19 Zodiacal Light 3:23 – 4:23 a.m. East
20 Zodiacal Light 3:24 – 4:24 a.m. East	21 Zodiacal Light 3:24 – 4:24 a.m. East	22 Zodiacal Light 3:25 – 4:25 a.m. East	23 Zodiacal Light 3:26 – 4:26 a.m. East	24 Zodiacal Light 3:27 – 4:27 a.m. East	25 Zodiacal Light 3:28 – 4:28 a.m. East	26 Zodiacal Light 3:29 – 4:29 a.m. East
27 Zodiacal Light 3:30 – 4:30 a.m. East	28 Zodiacal Light 3:31 – 4:31 a.m. East	29 Zodiacal Light 4:03 – 4:31 a.m. East	30	31

September 2023

SUN	MON	TUE	WED	THU	FRI	SAT
					1	2
3	4	5	6	7	8	9
10	11	12	13 Zodiacal Light 3:43 – 4:43 a.m. East	14 Zodiacal Light 3:44 – 4:44 a.m. East	15 Zodiacal Light 3:45 – 4:45 a.m. East	16 Zodiacal Light 3:46 – 4:46 a.m. East
17 Zodiacal Light 3:46 – 4:46 a.m. East	18 Zodiacal Light 3:47 – 4:47 a.m. East	19 Zodiacal Light 3:48 – 4:48 a.m. East	20 Zodiacal Light 3:49 – 4:49 a.m. East	21 Zodiacal Light 3:49 – 4:49 a.m. East	22 Zodiacal Light 3:50 – 4:50 a.m. East	23 Zodiacal Light 3:51 – 4:51 a.m. East
24 Zodiacal Light 3:51 – 4:51 a.m. East	25 Zodiacal Light 3:52 – 4:52 a.m. East	26 Zodiacal Light 3:53 – 4:53 a.m. East	27 Zodiacal Light 4:06 – 4:53 a.m. East	28	29	30

October 2023

SUN	MON	TUE	WED	THU	FRI	SAT
1	2	3	4	5	6	7
8	9	10	11	12	13 Zodiacal Light 4:04 – 5:04 a.m. East	14 Zodiacal Light 4:05 – 5:05 a.m. East
15 Zodiacal Light 4:06 – 5:06 a.m. East	16 Zodiacal Light 4:06 – 5:06 a.m. East	17 Zodiacal Light 4:07 – 5:07 a.m. East	18 Zodiacal Light 4:08 – 5:08 a.m. East	19 Zodiacal Light 4:08 – 5:08 a.m. East	20 Zodiacal Light 4:09 – 5:09 a.m. East	21 Zodiacal Light 4:10 – 5:10 a.m. East
22 Zodiacal Light 4:11 – 5:11 a.m. East	23 Zodiacal Light 4:11 – 5:11 a.m. East	24 Zodiacal Light 4:12 – 5:12 a.m. East	25 Zodiacal Light 4:13 – 5:13 a.m. East	26 Zodiacal Light 4:13 – 5:13 a.m. East	27	28
29	30	31

November 2023

SUN	MON	TUE	WED	THU	FRI	SAT
			1	2	3	4
5	6	7	8	9	10	11
12 Zodiacal Light 4:26 – 5:26 a.m. East	13 Zodiacal Light 4:27 – 5:27 a.m. East	14 Zodiacal Light 4:27 – 5:27 a.m. East	15 Zodiacal Light 4:28 – 5:28 a.m. East	16 Zodiacal Light 4:29 – 5:29 a.m. East	17 Zodiacal Light 4:30 – 5:30 a.m. East	18 Zodiacal Light 4:30 – 5:30 a.m. East
19 Zodiacal Light 4:31 – 5:31 a.m. East	20 Zodiacal Light 4:32 – 5:32 a.m. East	21 Zodiacal Light 4:33 – 5:33 a.m. East	22 Zodiacal Light 4:33 – 5:33 a.m. East	23 Zodiacal Light 4:34 – 5:34 a.m. East	24 Zodiacal Light 4:35 – 5:35 a.m. East	25 Zodiacal Light 5:13 – 5:36 a.m. East
26	27	28	29	30

December 2023

SUN	MON	TUE	WED	THU	FRI	SAT
					1	2
3	4	5	6	7	8	9
10	11 Zodiacal Light 4:47 – 5:47 a.m. East	12 Zodiacal Light 4:48 – 5:48 a.m. East	13 Zodiacal Light 4:48 – 5:48 a.m. East	14 Zodiacal Light 4:49 – 5:49 a.m. East	15 Zodiacal Light 4:50 – 5:50 a.m. East	16 Zodiacal Light 4:50 – 5:50 a.m. East
17 Zodiacal Light 4:51 – 5:51 a.m. East	18 Zodiacal Light 4:51 – 5:51 a.m. East	19 Zodiacal Light 4:52 – 5:52 a.m. East	20 Zodiacal Light 4:53 – 5:53 a.m. East	21 Zodiacal Light 4:53 – 5:53 a.m. East	22 Zodiacal Light 4:54 – 5:54 a.m. East	23 Zodiacal Light 4:54 – 5:54 a.m. East
24 Zodiacal Light 5:14 – 5:54 a.m. East	25	26	27	28	29	30
31

The best nights to observe the zodiacal light at mid-northern latitudes occur when the ecliptic plane intersects the horizon at an angle of 60° or steeper. The dates above were chosen on that basis, with the Sun at least 18° below the horizon and the Moon below the horizon being used to calculate the times. An interval of time of one hour either before morning twilight or after evening twilight was chosen arbitrarily because it is the “best one hour” for observing the zodiacal light. The zodiacal light cone will be brightest and will reach highest above the horizon when the Sun is 18° below the horizon (astronomical twilight), but no less.

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

$\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta$

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

Zodiacal Light.sas Download

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.

In 2022, the best dates and times for observing the zodiacal light are listed in the calendar below. The sky must be very clear with little or no light pollution. The specific times listed are for Dodgeville, Wisconsin (42° 58′ N, 90° 08′ W).

Here’s a nicely-formatted printable PDF file of the zodiacal light calendar:

Zodiacal Light Calendar 2022 Download

January 2022

SUN	MON	TUE	WED	THU	FRI	SAT
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	19 Zodiacal Light 6:36 – 6:38 p.m. West	20 Zodiacal Light 6:37 – 7:37 p.m. West	21 Zodiacal Light 6:38 – 7:38 p.m. West	22 Zodiacal Light 6:39 – 7:39 p.m. West
23 Zodiacal Light 6:40 – 7:40 p.m. West	24 Zodiacal Light 6:41 – 7:41 p.m. West	25 Zodiacal Light 6:42 – 7:42 p.m. West	26 Zodiacal Light 6:43 – 7:43 p.m. West	27 Zodiacal Light 6:44 – 7:44 p.m. West	28 Zodiacal Light 6:46 – 7:46 p.m. West	29 Zodiacal Light 6:47 – 7:47 p.m. West
30 Zodiacal Light 6:48 – 7:48 p.m. West	31 Zodiacal Light 6:49 – 7:49 p.m. West

February 2022

SUN	MON	TUE	WED	THU	FRI	SAT
		1 Zodiacal Light 6:50 – 7:50 p.m. West	2 Zodiacal Light 7:04 – 7:51 p.m. West	3	4	5
6	7	8	9	10	11	12
13	14	15	16	17	18 Zodiacal Light 7:10 – 7:51 p.m. West	19 Zodiacal Light 7:12 – 8:12 p.m. West
20 Zodiacal Light 7:13 – 8:13 p.m. West	21 Zodiacal Light 7:14 – 8:14 p.m. West	22 Zodiacal Light 7:15 – 8:15 p.m. West	23 Zodiacal Light 7:16 – 8:16 p.m. West	24 Zodiacal Light 7:18 – 8:18 p.m. West	25 Zodiacal Light 7:19 – 8:19 p.m. West	26 Zodiacal Light 7:20 – 8:20 p.m. West
27 Zodiacal Light 7:21 – 8:21 p.m. West	28 Zodiacal Light 7:22 – 8:22 p.m. West

March 2022

SUN	MON	TUE	WED	THU	FRI	SAT
		1 Zodiacal Light 7:24 – 8:24 p.m. West	2 Zodiacal Light 7:25 – 8:25 p.m. West	3 Zodiacal Light 7:26 – 8:26 p.m. West	4 Zodiacal Light 8:14 – 8:27 p.m. West	5
6	7	8	9	10	11	12
13	14	15	16	17	18	19 Zodiacal Light 8:47 – 8:59 p.m. West
20 Zodiacal Light 8:48 – 9:48 p.m. West	21 Zodiacal Light 8:49 – 9:49 p.m. West	22 Zodiacal Light 8:51 – 9:51 p.m. West	23 Zodiacal Light 8:52 – 9:52 p.m. West	24 Zodiacal Light 8:53 – 9:53 p.m. West	25 Zodiacal Light 8:55 – 9:55 p.m. West	26 Zodiacal Light 8:56 – 9:56 p.m. West
27 Zodiacal Light 8:57 – 9:57 p.m. West	28 Zodiacal Light 8:59 – 9:59 p.m. West	29 Zodiacal Light 9:00 – 10:00 p.m. West	30 Zodiacal Light 9:02 – 10:02 p.m. West	31 Zodiacal Light 9:03 – 10:03 p.m. West

April 2022

May 2022

June 2022

July 2022

August 2022

September 2022

SUN	MON	TUE	WED	THU	FRI	SAT
				1 Zodiacal Light 3:44 – 4:44 a.m. East	2 Zodiacal Light 3:45 – 4:45 a.m. East	3 Zodiacal Light 3:47 – 4:47 a.m. East
4 Zodiacal Light 3:48 – 4:48 a.m. East	5 Zodiacal Light 3:49 – 4:49 a.m. East	6 Zodiacal Light 3:51 – 4:51 a.m. East	7 Zodiacal Light 3:52 – 4:52 a.m. East	8 Zodiacal Light 3:57 – 4:54 a.m. East	9	10
11	12	13	14	15	16	17
18	19	20	21	22	23	24 Zodiacal Light 4:14 – 5:14 a.m. East
25 Zodiacal Light 4:16 – 5:16 a.m. East	26 Zodiacal Light 4:17 – 5:17 a.m. East	27 Zodiacal Light 4:18 – 5:18 a.m. East	28 Zodiacal Light 4:19 – 5:19 a.m. East	29 Zodiacal Light 4:21 – 5:21 a.m. East	30 Zodiacal Light 4:22 – 5:22 a.m. East

October 2022

SUN	MON	TUE	WED	THU	FRI	SAT
						1 Zodiacal Light 4:23 – 5:23 a.m. East
2 Zodiacal Light 4:24 – 5:24 a.m. East	3 Zodiacal Light 4:25 – 5:25 a.m. East	4 Zodiacal Light 4:27 – 5:27 a.m. East	5 Zodiacal Light 4:28 – 5:28 a.m. East	6 Zodiacal Light 4:29 – 5:29 a.m. East	7 Zodiacal Light 4:30 – 5:30 a.m. East	8 Zodiacal Light 5:28 – 5:31 a.m. East
9	10	11	12	13	14	15
16	17	18	19	20	21	22
23 Zodiacal Light 4:48 – 5:12 a.m. East	24 Zodiacal Light 4:50 – 5:50 a.m. East	25 Zodiacal Light 4:51 – 5:51 a.m. East	26 Zodiacal Light 4:52 – 5:52 a.m. East	27 Zodiacal Light 4:53 – 5:53 a.m. East	28 Zodiacal Light 4:54 – 5:54 a.m. East	29 Zodiacal Light 4:55 – 5:55 a.m. East
30 Zodiacal Light 4:56 – 5:56 a.m. East	31 Zodiacal Light 4:57 – 5:57 a.m. East

November 2022

SUN	MON	TUE	WED	THU	FRI	SAT
		1 Zodiacal Light 4:59 – 5:59 a.m. East	2 Zodiacal Light 5:00 – 6:00 a.m. East	3 Zodiacal Light 5:01 – 6:01 a.m. East	4 Zodiacal Light 5:02 – 6:02 a.m. East	5 Zodiacal Light 5:03 – 6:03 a.m. East
6 Zodiacal Light 4:35 – 5:04 a.m. East	7	8	9	10	11	12
13	14	15	16	17	18	19
20	21	22 Zodiacal Light 4:21 – 5:21 a.m. East	23 Zodiacal Light 4:22 – 5:22 a.m. East	24 Zodiacal Light 4:23 – 5:23 a.m. East	25 Zodiacal Light 4:24 – 5:24 a.m. East	26 Zodiacal Light 4:25 – 5:25 a.m. East
27 Zodiacal Light 4:26 – 5:26 a.m. East	28 Zodiacal Light 4:27 – 5:27 a.m. East	29 Zodiacal Light 4:28 – 5:28 a.m. East	30 Zodiacal Light 4:29 – 5:29 a.m. East

December 2022

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

$\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta$

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

Zodiacal Light.sas Download

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.

In 2021, the best dates and times for observing the zodiacal light are listed in the calendar below. The sky must be very clear with little or no light pollution. The specific times listed are for Dodgeville, Wisconsin (42° 58′ N, 90° 08′ W).

Here’s a nicely-formatted printable PDF file of the zodiacal light calendar:

Zodiacal Light Calendar 2021 Download

January 2021

February 2021

SUN	MON	TUE	WED	THU	FRI	SAT
	1 Zodiacal Light 6:51 – 7:51 p.m. West	2 Zodiacal Light 6:52 – 7:52 p.m. West	3 Zodiacal Light 6:53 – 7:53 p.m. West	4 Zodiacal Light 6:54 – 7:54 p.m. West	5 Zodiacal Light 6:56 – 7:56 p.m. West	6 Zodiacal Light 6:57 – 7:57 p.m. West
7 Zodiacal Light 6:58 – 7:58 p.m. West	8 Zodiacal Light 6:59 – 7:59 p.m. West	9 Zodiacal Light 7:00 – 8:00 p.m. West	10 Zodiacal Light 7:02 – 8:02 p.m. West	11 Zodiacal Light 7:03 – 8:03 p.m. West	12 Zodiacal Light 7:04 – 8:04 p.m. West	13
14	15	16	17	18	19	20
21	22	23	24	25	26	27
28 Zodiacal Light 7:23 – 7:36 p.m. West

March 2021

SUN	MON	TUE	WED	THU	FRI	SAT
	1 Zodiacal Light 7:25 – 8:25 p.m. West	2 Zodiacal Light 7:26 – 8:26 p.m. West	3 Zodiacal Light 7:27 – 8:27 p.m. West	4 Zodiacal Light 7:28 – 8:28 p.m. West	5 Zodiacal Light 7:29 – 8:29 p.m. West	6 Zodiacal Light 7:31 – 8:31 p.m. West
7 Zodiacal Light 7:32 – 8:32 p.m. West	8 Zodiacal Light 7:33 – 8:33 p.m. West	9 Zodiacal Light 7:34 – 8:34 p.m. West	10 Zodiacal Light 7:36 – 8:36 p.m. West	11 Zodiacal Light 7:37 – 8:37 p.m. West	12 Zodiacal Light 7:38 – 8:38 p.m. West	13 Zodiacal Light 7:40 – 8:40 p.m. West
14 Zodiacal Light 8:41 – 9:41 p.m. West	15	16	17	18	19	20
21	22	23	24	25	26	27
28	29	30 Zodiacal Light 9:03 – 10:03 p.m. West	31 Zodiacal Light 9:04 – 10:04 p.m. West

April 2021

SUN	MON	TUE	WED	THU	FRI	SAT
				1 Zodiacal Light 9:05 – 10:05 p.m. West	2 Zodiacal Light 9:07 – 10:07 p.m. West	3 Zodiacal Light 9:08 – 10:08 p.m. West
4 Zodiacal Light 9:10 – 10:10 p.m. West	5 Zodiacal Light 9:11 – 10:11 p.m. West	6 Zodiacal Light 9:13 – 10:13 p.m. West	7 Zodiacal Light 9:14 – 10:14 p.m. West	8 Zodiacal Light 9:16 – 10:16 p.m. West	9 Zodiacal Light 9:17 – 10:17 p.m. West	10 Zodiacal Light 9:19 – 10:19 p.m. West
11 Zodiacal Light 9:20 – 10:20 p.m. West	12 Zodiacal Light 9:22 – 10:22 p.m. West	13 Zodiacal Light 9:24 – 10:24 p.m. West	14	15	16	17
18	19	20	21	22	23	24
25	26	27	28	29	30

May 2021

June 2021

July 2021

August 2021

September 2021

SUN	MON	TUE	WED	THU	FRI	SAT
			1	2	3	4
5	6 Zodiacal Light 3:52 – 4:52 a.m. East	7 Zodiacal Light 3:53 – 4:53 a.m. East	8 Zodiacal Light 3:54 – 4:54 a.m. East	9 Zodiacal Light 3:56 – 4:56 a.m. East	10 Zodiacal Light 3:57 – 4:57 a.m. East	11 Zodiacal Light 3:58 – 4:58 a.m. East
12 Zodiacal Light 4:00 – 5:00 a.m. East	13 Zodiacal Light 4:01 – 5:01 a.m. East	14 Zodiacal Light 4:02 – 5:02 a.m. East	15 Zodiacal Light 4:04 – 5:04 a.m. East	16 Zodiacal Light 4:05 – 5:05 a.m. East	17 Zodiacal Light 4:06 – 5:06 a.m. East	18 Zodiacal Light 4:08 – 5:08 a.m. East
19 Zodiacal Light 4:59 – 5:09 a.m. East	20	21	22	23	24	25
26	27	28	29	30

October 2021

SUN	MON	TUE	WED	THU	FRI	SAT
					1	2
3	4	5 Zodiacal Light 4:28 – 5:28 a.m. East	6 Zodiacal Light 4:30 – 5:30 a.m. East	7 Zodiacal Light 4:31 – 5:31 a.m. East	8 Zodiacal Light 4:32 – 5:32 a.m. East	9 Zodiacal Light 4:33 – 5:33 a.m. East
10 Zodiacal Light 4:34 – 5:34 a.m. East	11 Zodiacal Light 4:35 – 5:35 a.m. East	12 Zodiacal Light 4:37 – 5:37 a.m. East	13 Zodiacal Light 4:38 – 5:38 a.m. East	14 Zodiacal Light 4:39 – 5:39 a.m. East	15 Zodiacal Light 4:40 – 5:40 a.m. East	16 Zodiacal Light 4:41 – 5:41 a.m. East
17 Zodiacal Light 4:42 – 5:42 a.m. East	18 Zodiacal Light 5:03 – 5:43 a.m. East	19	20	21	22	23
24	25	26	27	28	29	30
31

November 2021

SUN	MON	TUE	WED	THU	FRI	SAT
	1	2	3	4 Zodiacal Light 5:03 – 6:03 a.m. East	5 Zodiacal Light 5:04 – 6:04 a.m. East	6 Zodiacal Light 5:05 – 6:05 a.m. East
7 Zodiacal Light 4:06 – 5:06 a.m. East	8 Zodiacal Light 4:07 – 5:07 a.m. East	9 Zodiacal Light 4:08 – 5:08 a.m. East	10 Zodiacal Light 4:09 – 5:09 a.m. East	11 Zodiacal Light 4:10 – 5:10 a.m. East	12 Zodiacal Light 4:12 – 5:12 a.m. East	13 Zodiacal Light 4:13 – 5:13 a.m. East
14 Zodiacal Light 4:14 – 5:14 a.m. East	15 Zodiacal Light 4:15 – 5:15 a.m. East	16 Zodiacal Light 4:16 – 5:16 a.m. East	17 Zodiacal Light 5:06 – 5:17 a.m. East	18	19	20
21	22	23	24	25	26	27
28	29	30

December 2021

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

$\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta$

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

Zodiacal Light.sas Download

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.

In 2020, the best dates and times for observing the zodiacal light are listed in the calendar below. The sky must be very clear with little or no light pollution. The specific times listed are for Dodgeville, Wisconsin (42° 58′ N, 90° 08′ W).

Here’s a nicely-formatted printable PDF file of the zodiacal light calendar:

Zodiacal Light Calendar 2020 Download

January 2020

SUN	MON	TUE	WED	THU	FRI	SAT
			1	2	3	4
5	6	7	8	9	10	11
12 Zodiacal Light 6:28 – 7:07 p.m. West	13 Zodiacal Light 6:29 – 7:29 p.m. West	14 Zodiacal Light 6:30 – 7:30 p.m. West	15 Zodiacal Light 6:31 – 7:31 p.m. West	16 Zodiacal Light 6:32 – 7:32 p.m. West	17 Zodiacal Light 6:33 – 7:33 p.m. West	18 Zodiacal Light 6:34 – 7:34 p.m. West
19 Zodiacal Light 6:35 – 7:35 p.m. West	20 Zodiacal Light 6:36 – 7:36 p.m. West	21 Zodiacal Light 6:37 – 7:37 p.m. West	22 Zodiacal Light 6:38 – 7:38 p.m. West	23 Zodiacal Light 6:39 – 7:39 p.m. West	24 Zodiacal Light 6:41 – 7:41 p.m. West	25 Zodiacal Light 6:42 – 7:42 p.m. West
26	27	28	29	30	31

February 2020

SUN	MON	TUE	WED	THU	FRI	SAT
						1
2	3	4	5	6	7	8
9	10 Zodiacal Light 7:00 – 7:17 p.m. West	11 Zodiacal Light 7:01 – 8:01 p.m. West	12 Zodiacal Light 7:03 – 8:03 p.m. West	13 Zodiacal Light 7:04 – 8:04 p.m. West	14 Zodiacal Light 7:05 – 8:05 p.m. West	15 Zodiacal Light 7:06 – 8:06 p.m. West
16 Zodiacal Light 7:07 – 8:07 p.m. West	17 Zodiacal Light 7:09 – 8:09 p.m. West	18 Zodiacal Light 7:10 – 8:10 p.m. West	19 Zodiacal Light 7:11 – 8:11 p.m. West	20 Zodiacal Light 7:12 – 8:12 p.m. West	21 Zodiacal Light 7:13 – 8:13 p.m. West	22 Zodiacal Light 7:15 – 8:15 p.m. West
23 Zodiacal Light 7:16 – 8:16 p.m. West	24 Zodiacal Light 7:17 – 8:17 p.m. West	25	26	27	28	29

March 2020

SUN	MON	TUE	WED	THU	FRI	SAT
1	2	3	4	5	6	7
8	9	10	11 Zodiacal Light 8:37 – 9:37 p.m. West	12 Zodiacal Light 8:38 – 9:38 p.m. West	13 Zodiacal Light 8:39 – 9:39 p.m. West	14 Zodiacal Light 8:41 – 9:41 p.m. West
15 Zodiacal Light 8:42 – 9:42 p.m. West	16 Zodiacal Light 8:43 – 9:43 p.m. West	17 Zodiacal Light 8:45 – 9:45 p.m. West	18 Zodiacal Light 8:46 – 9:46 p.m. West	19 Zodiacal Light 8:47 – 9:47 p.m. West	20 Zodiacal Light 8:49 – 9:49 p.m. West	21 Zodiacal Light 8:50 – 9:50 p.m. West
22 Zodiacal Light 8:51 – 9:51 p.m. West	23 Zodiacal Light 8:53 – 9:53 p.m. West	24 Zodiacal Light 8:54 – 9:54 p.m. West	25 Zodiacal Light 8:55 – 9:55 p.m. West	26	27	28
29	30	31

April 2020

SUN	MON	TUE	WED	THU	FRI	SAT
			1	2	3	4
5	6	7	8	9 Zodiacal Light 9:17 – 9:51 p.m. West	10 Zodiacal Light 9:19 – 10:19 p.m. West	11 Zodiacal Light 9:20 – 10:20 p.m. West
12 Zodiacal Light 9:22 – 10:22 p.m. West	13 Zodiacal Light 9:23 – 10:23 p.m. West	14 Zodiacal Light 9:25 – 10:25 p.m. West	15 Zodiacal Light 9:27 – 10:27 p.m. West	16 Zodiacal Light 9:28 – 10:28 p.m. West	17 Zodiacal Light 9:30 – 10:30 p.m. West	18 Zodiacal Light 9:31 – 10:31 p.m. West
19 Zodiacal Light 9:33 – 10:33 p.m. West	20 Zodiacal Light 9:35 – 10:35 p.m. West	21 Zodiacal Light 9:36 – 10:36 p.m. West	22 Zodiacal Light 9:38 – 10:38 p.m. West	23 Zodiacal Light 9:40 – 10:40 p.m. West	24 Zodiacal Light 9:41 – 10:41 p.m. West	25
26	27	28	29	30

September 2020

SUN	MON	TUE	WED	THU	FRI	SAT
		1	2	3	4	5
6	7	8	9	10	11	12
13	14	15	16 Zodiacal Light 4:05 – 5:05 a.m. East	17 Zodiacal Light 4:06 – 5:06 a.m. East	18 Zodiacal Light 4:07 – 5:07 a.m. East	19 Zodiacal Light 4:09 – 5:09 a.m. East
20 Zodiacal Light 4:10 – 5:10 a.m. East	21 Zodiacal Light 4:11 – 5:11 a.m. East	22 Zodiacal Light 4:13 – 5:13 a.m. East	23 Zodiacal Light 4:14 – 5:14 a.m. East	24 Zodiacal Light 4:15 – 5:15 a.m. East	25 Zodiacal Light 4:16 – 5:16 a.m. East	26 Zodiacal Light 4:17 – 5:17 a.m. East
27 Zodiacal Light 4:19 – 5:19 a.m. East	28 Zodiacal Light 4:20 – 5:20 a.m. East	29 Zodiacal Light 4:27 – 5:21 a.m. East	30

October 2020

SUN	MON	TUE	WED	THU	FRI	SAT
				1	2	3
4	5	6	7	8	9	10
11	12	13	14	15	16 Zodiacal Light 4:41 – 5:41 a.m. East	17 Zodiacal Light 4:42 – 5:42 a.m. East
18 Zodiacal Light 4:43 – 5:43 a.m. East	19 Zodiacal Light 4:44 – 5:44 a.m. East	20 Zodiacal Light 4:46 – 5:46 a.m. East	21 Zodiacal Light 4:47 – 5:47 a.m. East	22 Zodiacal Light 4:48 – 5:48 a.m. East	23 Zodiacal Light 4:49 – 5:49 a.m. East	24 Zodiacal Light 4:50 – 5:50 a.m. East
25 Zodiacal Light 4:51 – 5:51 a.m. East	26 Zodiacal Light 4:52 – 5:52 a.m. East	27 Zodiacal Light 4:53 – 5:53 a.m. East	28 Zodiacal Light 4:55 – 5:55 a.m. East	29 Zodiacal Light 5:24 – 5:56 a.m. East	30	31

November 2020

SUN	MON	TUE	WED	THU	FRI	SAT
1	2	3	4	5	6	7
8	9	10	11	12	13	14 Zodiacal Light 4:13 – 5:13 a.m. East
15 Zodiacal Light 4:15 – 5:15 a.m. East	16 Zodiacal Light 4:16 – 5:16 a.m. East	17 Zodiacal Light 4:17 – 5:17 a.m. East	18 Zodiacal Light 4:18 – 5:18 a.m. East	19 Zodiacal Light 4:19 – 5:19 a.m. East	20 Zodiacal Light 4:20 – 5:20 a.m. East	21 Zodiacal Light 4:21 – 5:21 a.m. East
22 Zodiacal Light 4:22 – 5:22 a.m. East	23 Zodiacal Light 4:23 – 5:23 a.m. East	24 Zodiacal Light 4:24 – 5:24 a.m. East	25 Zodiacal Light 4:25 – 5:25 a.m. East	26 Zodiacal Light 4:26 – 5:26 a.m. East	27 Zodiacal Light 4:27 – 5:27 a.m. East	28 Zodiacal Light 5:17 – 5:28 a.m. East
29	30

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

$\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta$

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

Zodiacal Light.sas Download

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.

1
Zodiacal Light 9:05 – 10:05 p.m. West

2
Zodiacal Light 9:11 – 10:06 p.m. West

In this year of 2019, the best dates and times for observing the zodiacal light are listed below. The sky must be very clear with little or no light pollution. The specific times listed are for Dodgeville, Wisconsin.

2019	Begin	End	Direction
Tue. Jan. 22	6:39 p.m.	7:03 p.m.	West
Wed. Jan. 23	6:40 p.m.	7:40 p.m.	West
Thu. Jan. 24	6:41 p.m.	7:41 p.m.	West
Fri. Jan. 25	6:42 p.m.	7:42 p.m.	West
Sat. Jan. 26	6:43 p.m.	7:43 p.m.	West
Sun. Jan. 27	6:44 p.m.	7:44 p.m.	West
Mon. Jan. 28	6:45 p.m.	7:45 p.m.	West
Tue. Jan. 29	6:46 p.m.	7:46 p.m.	West
Wed. Jan. 30	6:48 p.m.	7:48 p.m.	West
Thu. Jan. 31	6:49 p.m.	7:49 p.m.	West
Fri. Feb. 1	6:50 p.m.	7:50 p.m.	West
Sat. Feb. 2	6:51 p.m.	7:51 p.m.	West
Sun. Feb. 3	6:52 p.m.	7:52 p.m.	West
Mon. Feb. 4	6:53 p.m.	7:53 p.m.	West
Tue. Feb. 5	6:55 p.m.	7:55 p.m.	West
Wed. Feb. 6	7:09 p.m.	7:56 p.m.	West

Thu. Feb. 21	7:14 p.m.	8:14 p.m.	West
Fri. Feb. 22	7:15 p.m.	8:15 p.m.	West
Sat. Feb. 23	7:16 p.m.	8:16 p.m.	West
Sun. Feb. 24	7:17 p.m.	8:17 p.m.	West
Mon. Feb. 25	7:19 p.m.	8:19 p.m.	West
Tue. Feb. 26	7:20 p.m.	8:20 p.m.	West
Wed. Feb. 27	7:21 p.m.	8:21 p.m.	West
Thu. Feb. 28	7:22 p.m.	8:22 p.m.	West
Fri. Mar. 1	7:23 p.m.	8:23 p.m.	West
Sat. Mar. 2	7:25 p.m.	8:25 p.m.	West
Sun. Mar. 3	7:26 p.m.	8:26 p.m.	West
Mon. Mar. 4	7:27 p.m.	8:27 p.m.	West
Tue. Mar. 5	7:28 p.m.	8:28 p.m.	West
Wed. Mar. 6	7:30 p.m.	8:30 p.m.	West
Thu. Mar. 7	7:31 p.m.	8:31 p.m.	West
Fri. Mar. 8	8:01 p.m.	8:32 p.m.	West

Fri. Mar. 22	8:50 p.m.	9:24 p.m.	West
Sat. Mar. 23	8:52 p.m.	9:52 p.m.	West
Sun. Mar. 24	8:53 p.m.	9:53 p.m.	West
Mon. Mar. 25	8:54 p.m.	9:54 p.m.	West
Tue. Mar. 26	8:56 p.m.	9:56 p.m.	West
Wed. Mar. 27	8:57 p.m.	9:57 p.m.	West
Thu. Mar. 28	8:59 p.m.	9:59 p.m.	West
Fri. Mar. 29	9:00 p.m.	10:00 p.m.	West
Sat. Mar. 30	9:01 p.m.	10:01 p.m.	West
Sun. Mar. 31	9:03 p.m.	10:03 p.m.	West
Mon. Apr. 1	9:04 p.m.	10:04 p.m.	West
Tue. Apr. 2	9:06 p.m.	10:06 p.m.	West
Wed. Apr. 3	9:07 p.m.	10:07 p.m.	West
Thu. Apr. 4	9:09 p.m.	10:09 p.m.	West
Fri. Apr. 5	9:10 p.m.	10:10 p.m.	West
Sat. Apr. 6	9:12 p.m.	10:12 p.m.	West
Sun. Apr. 7	10:03 p.m.	10:13 p.m.	West

Thu. Aug. 29	3:39 a.m.	4:39 a.m.	East
Fri. Aug. 30	3:40 a.m.	4:40 a.m.	East
Sat. Aug. 31	3:42 a.m.	4:42 a.m.	East
Sun. Sep. 1	3:43 a.m.	4:43 a.m.	East
Mon. Sep. 2	3:45 a.m.	4:45 a.m.	East
Tue. Sep. 3	3:46 a.m.	4:46 a.m.	East
Wed. Sep. 4	3:48 a.m.	4:48 a.m.	East
Thu. Sep. 5	3:49 a.m.	4:49 a.m.	East
Fri. Sep. 6	3:50 a.m.	4:50 a.m.	East
Sat. Sep. 7	3:52 a.m.	4:52 a.m.	East
Sun. Sep. 8	3:53 a.m.	4:53 a.m.	East
Mon. Sep. 9	3:55 a.m.	4:55 a.m.	East
Tue. Sep. 10	3:56 a.m.	4:56 a.m.	East
Wed. Sep. 11	3:57 a.m.	4:57 a.m.	East
Thu. Sep. 12	4:52 a.m.	4:59 a.m.	East

Fri. Sep. 27	5:11 a.m.	5:18 a.m.	East
Sat. Sep. 28	4:19 a.m.	5:19 a.m.	East
Sun. Sep. 29	4:20 a.m.	5:20 a.m.	East
Mon. Sep. 30	4:21 a.m.	5:21 a.m.	East
Tue. Oct. 1	4:23 a.m.	5:23 a.m.	East
Wed. Oct. 2	4:24 a.m.	5:24 a.m.	East
Thu. Oct. 3	4:25 a.m.	5:25 a.m.	East
Fri. Oct. 4	4:26 a.m.	5:26 a.m.	East
Sat. Oct. 5	4:27 a.m.	5:27 a.m.	East
Sun. Oct. 6	4:29 a.m.	5:29 a.m.	East
Mon. Oct. 7	4:30 a.m.	5:30 a.m.	East
Tue. Oct. 8	4:31 a.m.	5:31 a.m.	East
Wed. Oct. 9	4:32 a.m.	5:32 a.m.	East
Thu. Oct. 10	4:33 a.m.	5:33 a.m.	East
Fri. Oct. 11	4:43 a.m.	5:34 a.m.	East

Sat. Oct. 26	4:51 a.m.	5:19 a.m.	East
Sun. Oct. 27	4:53 a.m.	5:53 a.m.	East
Mon. Oct. 28	4:54 a.m.	5:54 a.m.	East
Tue. Oct. 29	4:55 a.m.	5:55 a.m.	East
Wed. Oct. 30	4:56 a.m.	5:56 a.m.	East
Thu. Oct. 31	4:57 a.m.	5:57 a.m.	East
Fri. Nov. 1	4:58 a.m.	5:58 a.m.	East
Sat. Nov. 2	4:59 a.m.	5:59 a.m.	East
Sun. Nov. 3	4:01 a.m.	5:01 a.m.	East
Mon. Nov. 4	4:02 a.m.	5:02 a.m.	East
Tue. Nov. 5	4:03 a.m.	5:03 a.m.	East
Wed. Nov. 6	4:04 a.m.	5:04 a.m.	East
Thu. Nov. 7	4:05 a.m.	5:05 a.m.	East
Fri. Nov. 8	4:06 a.m.	5:06 a.m.	East
Sat. Nov. 9	4:07 a.m.	5:07 a.m.	East
Sun. Nov. 10	4:34 a.m.	5:08 a.m.	East

Sun. Nov. 24	4:23 a.m.	4:27 a.m.	East
Mon. Nov. 25	4:24 a.m.	5:24 a.m.	East
Tue. Nov. 26	4:25 a.m.	5:25 a.m.	East
Wed. Nov. 27	4:26 a.m.	5:26 a.m.	East
Thu. Nov. 28	4:27 a.m.	5:27 a.m.	East
Fri. Nov. 29	4:28 a.m.	5:28 a.m.	East
Sat. Nov. 30	4:29 a.m.	5:29 a.m.	East
Sun. Dec. 1	4:30 a.m.	5:30 a.m.	East
Mon. Dec. 2	4:31 a.m.	5:31 a.m.	East
Tue. Dec. 3	4:32 a.m.	5:32 a.m.	East
Wed. Dec. 4	4:33 a.m.	5:33 a.m.	East
Thu. Dec. 5	4:34 a.m.	5:34 a.m.	East
Fri. Dec. 6	4:35 a.m.	5:35 a.m.	East
Sat. Dec. 7	4:35 a.m.	5:35 a.m.	East
Sun. Dec. 8	4:36 a.m.	5:36 a.m.	East
Mon. Dec. 9	4:37 a.m.	5:37 a.m.	East
Tue. Dec. 10	5:29 a.m.	5:38 a.m.	East

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

$\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta$

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

Zodiacal Light.sas Download

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.