Zodiacal Light 2018

In this year of 2018, the best dates and times for observing the zodiacal light are listed below.  The sky must be very clear.  The specific times listed are for Dodgeville, Wisconsin.

2018 Begin End Direction
Fri. Feb. 2 6:52 p.m. 7:52 p.m. West
Sat. Feb. 3 6:53 p.m. 7:53 p.m. West
Sun. Feb. 4 6:54 p.m. 7:54 p.m. West
Mon. Feb. 5 6:55 p.m. 7:55 p.m. West
Tue. Feb. 6 6:57 p.m. 7:57 p.m. West
Wed. Feb. 7 6:58 p.m. 7:58 p.m. West
Thu. Feb. 8 6:59 p.m. 7:59 p.m. West
Fri. Feb. 9 7:00 p.m. 8:00 p.m. West
Sat. Feb. 10 7:01 p.m. 8:01 p.m. West
Sun. Feb. 11 7:02 p.m. 8:02 p.m. West
Mon. Feb. 12 7:04 p.m. 8:04 p.m. West
Tue. Feb. 13 7:05 p.m. 8:05 p.m. West
Wed. Feb. 14 7:06 p.m. 8:06 p.m. West
Thu. Feb. 15 7:07 p.m. 8:07 p.m. West
Fri. Feb. 16 7:08 p.m. 8:08 p.m. West
Sat. Mar. 3 7:27 p.m. 7:59 p.m. West
Sun. Mar. 4 7:28 p.m. 8:28 p.m. West
Mon. Mar. 5 7:29 p.m. 8:29 p.m. West
Tue. Mar. 6 7:30 p.m. 8:30 p.m. West
Wed. Mar. 7 7:32 p.m. 8:32 p.m. West
Thu. Mar. 8 7:33 p.m. 8:33 p.m. West
Fri. Mar. 9 7:34 p.m. 8:34 p.m. West
Sat. Mar. 10 7:35 p.m. 8:35 p.m. West
Sun. Mar. 11 8:37 p.m. 9:37 p.m. West
Mon. Mar. 12 8:38 p.m. 9:38 p.m. West
Tue. Mar. 13 8:39 p.m. 9:39 p.m. West
Wed. Mar. 14 8:41 p.m. 9:41 p.m. West
Thu. Mar. 15 8:42 p.m. 9:42 p.m. West
Fri. Mar. 16 8:43 p.m. 9:43 p.m. West
Sat. Mar. 17 8:44 p.m. 9:44 p.m. West
Sun. Mar. 18 8:46 p.m. 9:46 p.m. West
Mon. Mar. 19 9:38 p.m. 9:47 p.m. West
Mon. Apr. 2 9:06 p.m. 9:56 p.m. West
Tue. Apr. 3 9:08 p.m. 10:08 p.m. West
Wed. Apr. 4 9:09 p.m. 10:09 p.m. West
Thu. Apr. 5 9:11 p.m. 10:11 p.m. West
Fri. Apr. 6 9:12 p.m. 10:12 p.m. West
Sat. Apr. 7 9:14 p.m. 10:14 p.m. West
Sun. Apr. 8 9:15 p.m. 10:15 p.m. West
Mon. Apr. 9 9:17 p.m. 10:17 p.m. West
Tue. Apr. 10 9:18 p.m. 10:18 p.m. West
Wed. Apr. 11 9:20 p.m. 10:20 p.m. West
Thu. Apr. 12 9:21 p.m. 10:21 p.m. West
Fri. Apr. 13 9:23 p.m. 10:23 p.m. West
Sat. Apr. 14 9:25 p.m. 10:25 p.m. West
Sun. Apr. 15 9:26 p.m. 10:26 p.m. West
Mon. Apr. 16 9:28 p.m. 10:28 p.m. West
Tue. Apr. 17 9:43 p.m. 10:29 p.m. West
Thu. Aug. 9 3:08 a.m. 3:44 a.m. East
Fri. Aug. 10 3:09 a.m. 4:09 a.m. East
Sat. Aug. 11 3:11 a.m. 4:11 a.m. East
Sun. Aug. 12 3:13 a.m. 4:13 a.m. East
Mon. Aug. 13 3:14 a.m. 4:14 a.m. East
Tue. Aug. 14 3:16 a.m. 4:16 a.m. East
Wed. Aug. 15 3:18 a.m. 4:18 a.m. East
Thu. Aug. 16 3:19 a.m. 4:19 a.m. East
Fri. Aug. 17 3:21 a.m. 4:21 a.m. East
Sat. Aug. 18 3:22 a.m. 4:22 a.m. East
Sun. Aug. 19 3:24 a.m. 4:24 a.m. East
Mon. Aug. 20 3:26 a.m. 4:26 a.m. East
Tue. Aug. 21 3:27 a.m. 4:27 a.m. East
Wed. Aug. 22 3:29 a.m. 4:29 a.m. East
Thu. Aug. 23 3:30 a.m. 4:30 a.m. East
Fri. Aug. 24 4:20 a.m. 4:32 a.m. East
Sat. Sep. 8 3:54 a.m. 4:54 a.m. East
Sun. Sep. 9 3:55 a.m. 4:55 a.m. East
Mon. Sep. 10 3:57 a.m. 4:57 a.m. East
Tue. Sep. 11 3:58 a.m. 4:58 a.m. East
Wed. Sep. 12 3:59 a.m. 4:59 a.m. East
Thu. Sep. 13 4:01 a.m. 5:01 a.m. East
Fri. Sep. 14 4:02 a.m. 5:02 a.m. East
Sat. Sep. 15 4:03 a.m. 5:03 a.m. East
Sun. Sep. 16 4:05 a.m. 5:05 a.m. East
Mon. Sep. 17 4:06 a.m. 5:06 a.m. East
Tue. Sep. 18 4:07 a.m. 5:07 a.m. East
Wed. Sep. 19 4:09 a.m. 5:09 a.m. East
Thu. Sep. 20 4:10 a.m. 5:10 a.m. East
Fri. Sep. 21 4:11 a.m. 5:11 a.m. East
Sat. Sep. 22 4:12 a.m. 5:12 a.m. East
Sun. Sep. 23 5:07 a.m. 5:14 a.m. East
Sun. Oct. 7 4:30 a.m. 5:04 a.m. East
Mon. Oct. 8 4:32 a.m. 5:32 a.m. East
Tue. Oct. 9 4:33 a.m. 5:33 a.m. East
Wed. Oct. 10 4:34 a.m. 5:34 a.m. East
Thu. Oct. 11 4:35 a.m. 5:35 a.m. East
Fri. Oct. 12 4:36 a.m. 5:36 a.m. East
Sat. Oct. 13 4:37 a.m. 5:37 a.m. East
Sun. Oct. 14 4:39 a.m. 5:39 a.m. East
Mon. Oct. 15 4:40 a.m. 5:40 a.m. East
Tue. Oct. 16 4:41 a.m. 5:41 a.m. East
Wed. Oct. 17 4:42 a.m. 5:42 a.m. East
Thu. Oct. 18 4:43 a.m. 5:43 a.m. East
Fri. Oct. 19 4:44 a.m. 5:44 a.m. East
Sat. Oct. 20 4:45 a.m. 5:45 a.m. East
Sun. Oct. 21 4:47 a.m. 5:47 a.m. East
Mon. Oct. 22 4:57 a.m. 5:48 a.m. East

On the February, March, and April evenings listed above, you will see a broad, faint band of light extending upwards from the western horizon, sloping a little to the left, and reaching nearly halfway to the top of the sky.

On the August, September, and October mornings listed above, you will see a broad, faint band of light extending upwards from the eastern horizon, sloping a little to the right, and reaching nearly halfway to the top of the sky.

It is essential that your view is not spoiled by nearby streetlights, parking lot lights, or dusk-to-damn insecurity lights, nor any city to the west (Feb-Apr) or east (Aug-Oct).  Give your eyes a few minutes to adjust to the darkness.  Slowly sweeping your eyes back and forth from southwest to northwest (Feb-Apr) or northeast to southeast (Aug-Oct) will help you spot the zodiacal light band.  Once spotted, you should be able to see it without moving your head.

On the February, March, and April evenings listed above, the zodiacal light is best seen right at the end of evening twilight, and remains visible for an hour or so after that.

On the August, September, and October mornings listed above, the zodiacal light is best seen about an hour or so before the beginning of morning twilight, right up to the beginning of morning twilight.


2 thoughts on “Zodiacal Light 2018”

  1. It is nice to see such a prediction about Zodiacal lights.
    Can you please calculate the local times when such lights will be visible from places at the Tropic of Cancer and at Equator?
    Can you share the formula for such calculations?

  2. Dear Dr. Ahmed,

    The best times to see the zodiacal light is when the ecliptic is most nearly perpendicular to the horizon, right after the end of astronomical twilight (Sun altitude -18°) in the evening, and right before the beginning of astronomical twilight in the morning. The following diagrams will show you the angle the ecliptic makes with the horizon on the 15th of each month of the year for latitudes 43°N (Dodgeville, WI), 23°26’12.8″N (Tropic of Cancer), and 0° (The Equator).

    Zodiacal Light – A.M.

    Zodiacal Light – P.M.

    I was surprised to find that the best mid-months for morning zodiacal light is actually September, October, and November (and not so much August) at both latitudes 43°N and 23°N, though you can see the ecliptic makes a much more perpendicular angle with the horizon at 23°N. So, along the Tropic of Cancer, the zodiacal light will be easier to see in other months, too. When I lived in Alpine, Texas (latitude 30°N), I indeed noticed that the zodiacal light was more impressive than my experiences seeing it further north.

    Similarly, the best mid-months for evening zodiacal light is actually January, February, and March (and not so much April) at both latitudes 43°N and 23°N. Again, the ecliptic makes a steeper angle with the horizon at the Tropic of Cancer.

    The situation at the Equator is a bit different. January and July are the best months for morning zodiacal light there, and May-June and November-December for the evening zodiacal light.

    The other factor to consider (besides minimal to no light pollution) for picking zodiacal light viewing times is no lunar interference. Any good planetarium software will allow you to find astronomical twilight for any date when the Moon isn’t above the horizon. I used Voyager 4.5. If you want to calculate the times when the Sun is 18° below the horizon and the Moon is below the horizon, there are several good books by Jean Meeus (and others) that show you how. I myself wrote such a program in Applesoft BASIC on an Apple ][+ computer back in 1981, and I have a version of it today written in SAS that I use to generate my Dark Skies page each month.

    In conclusion, I now realize that the best months for observing the zodiacal light this year perhaps should have excluded April and included January, and excluded August and included November. Of course, this will vary slightly from year to year depending on what time of the month presents moonless skies. When I publish Zodiacal Light 2019 next January, I will do a more careful analysis to make sure I get it right!

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