This is the companion Web Site of Bob Moler's Ephemeris radio program, which is broadcast Monday Through Friday on Interlochen Public Radio Stations. Interlochen Public Radio serves northwestern lower Michigan. The first Ephemeris program was broadcast June 1, 1975.
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Note that scripts for the programs plus illustrations and additional information are art of my blog, which can be clicked on above or here.
On this site – articles of interest for this month
Planetary Highlights for May 2022 (ET)
Date Time Event May 1 Su Venus: 42.4° W 1 Su 3:52 pm Moon Ascending Node 2 Mo 10:17 am Moon-Mercury: 2° N 5 Th 4:57 am Uranus Conjunction 5 Th 8:46 am Moon Apogee: 405300 km 5 Th 11:55 am Moon North Dec.: 27° N 6 Fr 4:00 am Eta Aquarid Shower: ZHR = 60 6 Fr 6:56 pm Moon-Pollux: 2.3° N 7 Sa 8:23 pm Moon-Beehive: 4° S 8 Su 8:21 pm First Quarter 15 Su 7:44 pm Moon Descending Node 16 Mo 12:11 am Total Lunar Eclipse See the article below 16 Mo 12:14 am Full Flower Moon 17 Tu 11:23 am Moon Perigee: 360300 km 18 We 9:21 pm Moon South Dec.: 27° S 21 Sa 3:14 pm Mercury Inferior Conj. 22 Su 12:43 am Moon-Saturn: 4.6° N 22 Su 2:43 pm Last Quarter 24 Tu 3:24 pm Moon-Mars: 2.9° N 24 Tu 7:59 pm Moon-Jupiter: 3.4° N 26 Th 10:52 pm Moon-Venus: 0.2° N 28 Sa 10:33 pm Moon Ascending Node 29 Su 4:57 am Mars-Jupiter: 0.6° N 30 Mo 7:30 am New Moon 31 Tu 1:00 am Tau Herculid Shower!? See the article below Jun 1 We Venus: 36.5° W
All event times are given for UTC-4:00: Eastern Daylight Time
Events Calendar by Fred Espenak and Sumit Dutta (NASA’s
If you go to the above site you can print out a list like the above for the entire year or calendar pages for your time zone.
Note that the site is now kept up for archival purposes. Fred Espenak retired from NASA several years ago and has his own site, AstroPixels, which contain much the same information: http://astropixels.com/almanac/almanac.html. However, he doesn’t adjust for Daylight Saving Time.
Lunar eclipses or eclipses of the Moon, as these events are also called, only occur at full moon when the Earth's shadow is cast upon the Moon. Unlike a solar eclipse, of which the partial phases are dangerous to gaze upon without special protection, a lunar eclipse is perfectly safe to view throughout.
There are three kinds of lunar eclipses or phases of lunar eclipses: penumbral, partial, and total. A total eclipse passes through all three phases. In the penumbra the Sun's light is increasingly cut off from the outside to the inside of the shadow called the umbra, where all direct sunlight is cut off. Depending on the path of the Moon, it can cut through only the penumbra, in which the eclipse is barely noticeable, a penumbral eclipse. The Moon can just clip the edge of the umbra, to create a partial eclipse. Or the Moon can be immersed completely in the umbra to produce a total eclipse.
Lunar eclipses are easiest to see, because one only has to be on the night side of the Earth to see it. In a solar eclipse, the Moon's shadow is too small to completely cover the Earth, since it's only a quarter the size of the Earth, so one has to be in a band a few thousand miles wide to spot the partial phase and has to be in a very narrow couple hundred mile wide, or less, path to see the brief totality. We'll revisit this in next year in preparation for two country spanning solar eclipses: an annular solar eclipse of October 14, 2023 and the total solar eclipse of April 8, 2024. These two eclipses will appear as partial eclipses here in Michigan.
Eclipses, both lunar and solar occur in seasons nearly 6 months apart, which usually have one of each kind two weeks apart. Occasionally with a central eclipse of one kind to have two of the other type two weeks before and two weeks after. The first eclipse of this eclipse season was a partial solar eclipse visible in the southeastern part of the Pacific Ocean and the southern tip of South America on April 30th.
The reason for eclipse seasons is because the Earth and Moon's orbits are tilted at about a 5° angle, and the point where they cross, 180° apart. Those crossing points, called nodes, are slowly rotating westward, completing a complete rotation in 18.6 years. This gives us two eclipse seasons a year that slowly move earlier in the calendar. It is only when the Sun within about 17.5 degrees from a node do we have a chance for an eclipse, otherwise the Moon is too far north or south. Eclipse seasons last about 35 days.
If you'd like to explore eclipses further, check out this NASA website: http://eclipse.gsfc.nasa.gov/eclipse.html. If you receive the pdf version of this newsletter and view it rather than print it, the above is an active link.
Contact times are labeled P1, U1, U2, U3, U4, and P4. P2 and P3 are omitted because they are synonymous with U1 and U4 respectively. Times are EDT unless noted (pm times are the 15th:
P1 – 9:32:07 pm (1:32:07 UT) Enter the penumbra (unseen). By about 9 pm (1:00 UT) the duskiness on the left edge of the moon will start to be noticeable.
U1 – 10:27:53 pm (2:27:53 UT) Enter the umbra (partial eclipse begins).
U2 – 11:29:03 pm (3:29:03 UT) Totality begins.
Mid eclipse 12:11:28.8 am (4:11:28.8 UT)
U3 – 12:53:56 am (4:53:56 UT) Totality ends, egress partial phase begins.
U4 – 1:55:07 am (5:55:07 UT) Partial phase ends. The Moon's upper right edge should appear dusky for the next half hour or so.
P4 – 2:50:48 am (6:50:48 UT) Penumbral phase ends (unseen).
Normally the penumbral effect on the Moon is only noticeable within a half hour or so before and after the partial phase of the eclipse. The duskiness of the penumbral phase of the eclipse can be enhanced by viewing through sunglasses.
During the total phase, light leaks in around the Earth due to the bending of light in the Earth's atmosphere, so the Moon is illuminated by the collective sunrises and sunsets around the globe. This usually gives the Moon a coppery hue, that some are now calling a blood moon. Occasionally, due to volcanic eruptions the Moon can become very dark, almost invisible to the naked eye.
This full moon in May is also called the Flower Moon and for those who care, also a supermoon. It will reach perigee a day and a half later. Throughout the night the Moon will be low in the southeastern part of the sky.
I almost missed this. While putting together this month's Stellar Sentinel the Extras section turned out to be corrupted. In reconstructing this section, I ran into an article I saved fom EarthSky.org: https://earthsky.org/astronomy-essentials/tau-herculid-meteors-may-intense-shower/. It was about a possible intense meteor shower from a comet that began to break up in 1995. The comet was 73P/Schwassmann-Wachmann 3 (SW3). I wrote about the comet and its many pieces that came around in 2006 in the May 2006 issue of the Stellar Sentinel. And I was actually able to spot three of the larger pieces with my telescope.
In 2006, 28 fragments were counted. In 2017 there were 2. This approach of this 5.44 year period comet so far shows only one fragment left, but it's early. Its perihelion is in late August, when the main fragment is expected to reach magnitude 12.
The swarm of meteoric fragments is supposed to pass the Earth at about 1 am (5 hr UT) May 31st. That's Memorial Day night. It's also the night after new moon. Despite the name of the shower, the radiant of this meteor shower is expected to be about a third of the way between Arcturus and Cor Caroli in Canes Venatici, near the globular cluster M 3. The information about the peak date and location of the radiant differs from that in the planetarium app Stellarium.
For more information :
International Meteor Organization https://www.imo.net/files/meteor-shower/cal2022.pdf, pages 9 and 10.
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