Archive
06/06/2022 – Ephemeris – In June we spend our evenings in the twilight zone
This is Ephemeris for Monday, June 6th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:25, and it will rise tomorrow at 5:57. The Moon, 1 day before first quarter, will set at 2:28 tomorrow morning
We spend our evenings after sunset during the months of June and July, pretty much in the twilight zone. Actually, it’s just twilight. There are three twilight periods: Civil, Nautical and Astronomical. In the evening, civil twilight lasts from sunset to when the Sun drops to 6 degrees below the horizon. The scene around is still quite bright, but car headlights still need to be on. Nautical twilight lasts until the Sun is 12 degrees below the horizon. Bright stars and the horizon are visible for sextant use. After that is astronomical twilight until the Sun is 18 degrees below the horizon, when the stars become more and more numerous. After that it’s officially dark, Moon permitting. This time of year we’re lucky to get three and a half hours of darkness.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Daylight, twilight, and dark example for June 6, 2022. This graph is centered on midnight. Light blue is daylight, while the three darker shades of blue denote the three twilight periods of civil, nautical and astronomical. The yellow lines show when the Sun, Moon and planets are visible. Dark of night is relegated only to the morning hours, thanks to the season, daylight saving time and our location 43 minutes west of our standard time meridian. The chart is produced by the app Cartes du Ciel (Sky Charts).
06/01/2022 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, June 1st. Today the Sun will be up for 15 hours and 21 minutes, setting at 9:21, and it will rise tomorrow at 5:59. The Moon, 2 days past new, will set at 11:49 this evening.
Let’s search for the naked-eye planets for this week. All the naked-eye planets are in the morning sky, although Mercury is too close to the Sun to be seen, and might just be visible low in the east-northeast after 5 am around mid-month. That’s at least for those as far north as we are. At 5 am tomorrow the planets will be spread out from brilliant Venus low in the east to Saturn higher in the south-southeast. To the right of Venus, tomorrow morning, in the east-southeast are Mars and Jupiter. Mars is quite a bit dimmer than Jupiter. All will be in line sloping to the upper right with Saturn all by its lonesome in the south-southeast. Though Mercury will enter the evening sky first, it won’t have great visibility. Saturn will enter the evening sky August 14th.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
The two-day-old Moon as it might be seen in binoculars tonight, June 1, 2022. Earth shine might illuminate the Moon’s night side. Created using Stellarium and GIMP.
Morning planets at 5 am tomorrow morning, June 2, 2022. Click on the image to enlarge it. The span of the planets from Venus to Saturn is 70 degrees. Click on the image to enlarge it. Created using Stellarium.
Views of Venus, Jupiter, and Saturn (north up) as they would be seen in a small telescope, with the same magnification, tomorrow morning at 5:00 am, June 2, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 13.58″, 78.3% illuminated; Saturn 17.40″, its rings 40.54″; Jupiter 37.49″. Mars is not shown, its apparent diameter is 6.46″ and is 87.2% illuminated. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts), planet information from Stellarium.
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on June 1, 2022. The night ends on the left with sunrise on the 2nd. Notice that all the naked-eye planets are in the morning sky now. Click on the image to enlarge it. Created using my LookingUp program.
Update on the Tau Herculid meteor shower of May 31st.
The meteor shower was rather weak. I saw one during an hour and a half of observing, slowly moving over the Big Dipper. The sky was “clear”, but there was a haze to it. It definitely wasn’t crystal clear. I’ve heard from others who had a bit more success.
05/30/2022 – Ephemeris – There might be a spectacular meteor shower/storm tonight after midnight!
This is Ephemeris for Memorial Day, Monday, May 30th. Today the Sun will be up for 15 hours and 18 minutes, setting at 9:19, and it will rise tomorrow at 6:00. The Moon is new today, and won’t be visible.
Comet Schwassmann-Wachmann 3, SW3 for short began to breakup in 1995, 27 years ago. Two large chunks of the comet’s nucleus and dozens of smaller pieces have been seen. We expect a vast debris field to be expanding from the remnants of the comet, unseen. Astronomers, calculating what happened to that unseen debris cloud, expect the Earth to run into a part of it around 1 am (EDT, 5 hours UT), give or take, tomorrow morning. Causing, if we’re lucky, a meteor shower or meteor storm. The radiant point from which the meteors seem to come is from between the Big Dipper’s handle and the bright star Arcturus. They will appear all over the sky. I’m crossing my fingers on this one, it could be great, or it could be nothing.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Position of the Tau Herculid radiant at 1 am, May 31, 2022. However, meteors will appear all over the sky, but could be traced back to the radiant. These meteors will appear to travel a lot slower than the Perseid meteors of August. Created using Stellarium for the star field and LibreOffice for annotations.
Comet Schwassmann-Wachmann 3 Hubble Space Telescope images from 2006 showing the breakup of the comet. Credit: NASA.
05/27/2022 – Ephemeris – There could be a spectacular meteor display Tuesday early morning, or nothing!
This is Bob Moler with Ephemeris for Friday, May 27th. Today the Sun will be up for 15 hours and 13 minutes, setting at 9:16, and it will rise tomorrow at 6:02. The Moon, 3 days before new, will rise at 5:03 tomorrow morning.
Comet Schwassmann-Wachmann 3, SW3 for short began to breakup in 1995, 27 years ago. Two large chunks of the comet’s nucleus and dozens of smaller pieces have been seen. A vast, unseen debris field is expected to be expanding from the remnants of the comet. Astronomers, calculating what happened to that unseen debris cloud, expect the Earth to run into a part of it around 1 am (EDT, 5 hours UT), give or take, on Tuesday, May 31st (That’s late Memorial Day night). Causing, if we’re lucky, a meteor shower or meteor storm. The radiant point from which the meteors seem to come is from between the Big Dipper’s handle and the bright star Arcturus. They will appear all over the sky. I’m crossing my fingers on this one, it could be great, or it could be nothing.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Position of the Tau Herculid radiant at 1 am, May 31, 2022. However, meteors will appear all over the sky, but could be traced back to the radiant. These meteors will appear to travel a lot slower than the Perseid meteors of August. Created using Stellarium for the star field and LibreOffice for annotations.
Comet Schwassmann-Wachmann 3 Hubble Space Telescope images from 2006 showing the breakup of the comet. Credit: NASA.
05/26/2022 – Ephemeris – There may be a spectacular meteor storm Tuesday am or nothing!
This is Ephemeris for Thursday, May 26th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:16, and it will rise tomorrow at 6:03. The Moon, halfway from last quarter to new, will rise at 4:42 tomorrow morning.
Early risers tomorrow morning should be able to see, if it’s clear, the planet Venus just above and right of the waning crescent Moon. The last of the visible Moon-planet encounters this month. Another event this month may be the Tau Herculid meteor shower. This may be a spectacular meteor shower, or nothing. It would be the result of the breakup of Comet Schwassmann-Wachmann 3 that started back in 1995. SW3, as it’s known for short, has a 5.44 year orbit of the Sun, so we only get a good look at it about every 11 years currently. As the nucleus breaks up, the debris field widens, with time. The comet will pass close to the orbit of the Earth in a few months. The comet’s orbit comes closest to the Earth’s orbit on May 31st. If the debris cloud has widened enough by now, the Earth should intercept it around 1 am our time that morning.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Position of the Tau Herculid radiant at 1 am, May 31, 2022. However, meteors will appear all over the sky, but could be traced back to the radiant. These meteors will appear to travel a lot slower than the Perseid meteors of August. The meteor storm, if it occurs, should peak around 1 am. However, there is an uncertainty with the time or if the meteor will show up. Created using Stellarium for the star field and LibreOffice for annotations.
Comet Schwassmann-Wachmann 3 Hubble Space Telescope images from 2006 showing the breakup of the comet. Credit: NASA.
05/25/2022 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, May 25th. Today the Sun will be up for 15 hours and 10 minutes, setting at 9:15, and it will rise tomorrow at 6:04. The Moon, 3 days past last quarter, will rise at 4:22 tomorrow morning. | Let’s search for the naked-eye planets for this week. All the naked-eye planets are back in the morning sky, although the newcomer, Mercury, is too close to the Sun to be seen, and may stay that way for the rest of its morning appearance. That’s at least for those as far north as we are (45° N). At 5 am tomorrow the planets will be spread out from brilliant Venus low in the east to Saturn higher in the southeast. To the right of Venus, tomorrow morning, will be the thin crescent Moon. Farther right is the quite bright Jupiter. Just to the right of Jupiter will be the dimmest of the 4, Mars, which is closing on Jupiter. The two will seem to pass each other on Sunday. All will be in line sloping to the upper right with Saturn all by its lonesome in the southeast.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
All the morning planets except Mercury, which is too close to the Sun to be seen, will be visible at 5 am tomorrow morning, May 26, 2022. The labels for Mars and Jupiter are on top of each other. Click on the image to enlarge it. Created using Stellarium.
The waning crescent moon as it might appear in binoculars tomorrow morning, May 26, 2022. Earth shine might also illuminate the Moon’s night side. Created using Stellarium.
Views of Venus, Jupiter, and Saturn (north up) as they would be seen in a small telescope, with the same magnification, tomorrow morning at 5:00 am, May 26, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 14.13″, 76.1% illuminated; Saturn 17.20″, its rings 40.06″; Jupiter 36.80″. Mars is not shown, its apparent diameter is 6.30″ and is 87.7% illuminated. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on May 25, 2022. The night ends on the left with sunrise on the 26th. Notice that all the naked-eye planets are in the morning sky now. Click on the image to enlarge it. Created using my LookingUp program.
05/23/2022 – Ephemeris – the Moon and the morning planets plus the Big Dipper’s stars Mizar and Alcor
This is Bob Moler with Ephemeris for Monday, May 23rd. Today the Sun will be up for 15 hours and 6 minutes, setting at 9:13, and it will rise tomorrow at 6:05. The Moon, 1 day past last quarter, will rise at 3:44 tomorrow morning.
This week, the Moon is in the process of passing the morning planets. This morning it passed Saturn. Tomorrow afternoon and evening it will pass Mars, then Jupiter. By Thursday morning, the Moon will be below and left of Jupiter. Thursday evening, it will pass Venus.
Back to tonight’s sky, the Big Dipper is nearly overhead. In its handle is a star or two that are interesting. It’s the star at the bend in the handle. It’s called Mizar. Next to it, for those with good eyesight, is a dimmer star, called Alcor. The name Mizar is from the Arabic, meaning apron or cover, while Alcor means the forgotten one. Before optometrists, the ability to actually see both stars was a test for good eyesight, especially for Arabic warriors. The pair is also known as the “Horse and the Rider”.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
The Moon passing the morning planets at 5 am 5/23/2022 to 5/27/2022. Click on the image to enlarge it. Created using Stellarium and GIMP.
Mizar and Alcor in the Big Dipper as it is nearly overhead towards the north. Click on the image to enlarge it. Created using Stellarium.
Alcor seems to be a true companion to Mizar, since they are at the same distance of 81.7 light years. Alcor also has an unseen companion star. Mizar also has a much closer companion star that can be seen in a telescope. On top of that, each of them has another unseen companion star. Six stars for the price of two. What a deal.
How can you detect a companion star that can’t be seen? When analyzing a star’s spectra, the companion star betrays it presence by its chemical absorption lines shifting with respect to its primary due to the Doppler effect of its motion.
05/20/2022 – Ephemeris – Spring constellations: Corvus the crow
This is Bob Moler with Ephemeris for Friday, May 20th. Today the Sun will be up for 15 hours even, setting at 9:09, and it will rise tomorrow at 6:08. The Moon, 2 days before last quarter, will rise at 2:23 tomorrow morning.
The small constellation of Corvus the crow is located low in the south at 10:30 this evening. It’s made of 6 dim stars, but the pattern is a distinctive but distorted box with two stars at the upper left marking that corner, and another two marking the lower right corner. I usually don’t notice the extra star at these corners, which denote the wings of this crow in flight to the upper right. To me the box is distinctive enough. It’s pretty much alone below Virgo and its bright star Spica, left an above it. I don’t see a crow here, but the box is distinctive in that no two sides are parallel. In the US we call the shape a trapezium, the British call it a trapezoid. Anyway it is a very memorable shape, at least to me.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Corvus the crow finder animation for 10:30 pm, May 20th. My visualization of the crow flying to the upper right doesn’t match the one the artist drew in this depiction. There’s no right or wrong. Created using Stellarium and GIMP.
05/19/2022 – Ephemeris – Spring constellations: Virgo
This is Ephemeris for Thursday, May 19th. Today the Sun will be up for 14 hours and 58 minutes, setting at 9:08, and it will rise tomorrow at 6:09. The Moon, halfway from full to last quarter, will rise at 1:40 tomorrow morning.
Tonight at 11 p.m. in the south is the constellation and member of the zodiac: Virgo the virgin. Virgo is a large constellation of a reclining woman holding a stalk of wheat. Spica, the bluest of the first magnitude stars, is the head of that spike of wheat; and as such it ruled over the harvest in two of Virgo’s guises as the goddesses Persephone and Ceres. Virgo is also identified as Astraea the goddess of justice. The constellation of Libra, the scales, which she is associated with, is found just east of her low in the southeast. Early Christians who sought to de-paganize the heavens saw Virgo as the Virgin Mary. Virgo is the host to a great cluster of galaxies seen far beyond its stars, which belong to our galaxy.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
Virgo finder animation with Libra added for 11 p.m. tonight, May 19th. Created using Stellarium and GIMP.
Virgo as depicted in Urania’s Mirror, a set of constellation cards published in London c.1825. From the Library of Congress. H/T Wikipedia.
Brighter members of the Virgo Cluster. Created using Stellarium. Open circles are galaxies, circles with crosses are globular star clusters, outlying members of our Milky Way galaxy.
05/12/2022 – Ephemeris – There will be a total eclipse of the Moon this Sunday night/Monday morning
This is Ephemeris for Thursday, May 12th. Today the Sun will be up for 14 hours and 43 minutes, setting at 9:01, and it will rise tomorrow at 6:16. The Moon, halfway from first quarter to full, will set at 5:06 tomorrow morning.
Late Sunday night through early Monday morning May 15/16 there will be a total eclipse of the Moon which will run from 10:28 pm Sunday night to 1:55 Monday morning. I’ll be more specific tomorrow. Also known as lunar eclipses, these only occur at full moon when the Moon crosses the earth’s shadow. Usually, the Moon passes too far north or south to run into earth’s shadow. In only in one in six full moons does this happen. To see it, one has to be on the night side of the Earth. And it has to be clear at your location, a big problem around here. Our last lunar eclipse in November was clouded out from my location, which is usually my luck with lunar eclipses. However, May is a better month. Here’s hoping.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.
Addendum
How lunar eclipses occur. Credit NASA/Fred Espenak.
The eclipse occurs on the 16th for Universal Time, because the eclipse events take place after 8 pm EDT on the 15th. The Moon travels through the Earth’s shadow from right to left. What are seen are points of contact with the shadow and mid-eclipse. On the world map, locations in the white or light part of the map can see all or part of the eclipse. From Five Millennium Canon of Lunar Eclipses (Espenak & Meeus) NASA, with additions by me.
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:
- P1 – 9:32:07 pm (1:32:07 UT) Enter the penumbra (unseen). By about 9 pm, the duskiness on the left edge of the moon will start to be noticeable. Wearing sunglasses to dim the bright Moon will help show the effect.
- 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, the 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).
