05/23/2022 – Ephemeris – the Moon and the morning planets plus the Big Dipper’s stars Mizar and Alcor

May 23, 2022 Leave a comment

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 5/23/22 to 5/27/22

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

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

May 20, 2022 Leave a comment

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 finder animation

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

May 19, 2022 Leave a comment

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

Virgo finder animation with Libra added for 11 p.m. tonight, May 19th. Created using Stellarium and GIMP.

Virgo

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.

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.

05/18/2022 – Ephemeris – Let’s search for the naked-eye planets for this week

May 18, 2022 Comments off

This is Ephemeris for Wednesday, May 18th. Today the Sun will be up for 14 hours and 56 minutes, setting at 9:07, and it will rise tomorrow at 6:10. The Moon, 2 days past full, will rise at 12:43 tomorrow morning.

Let’s search for the naked-eye planets for this week. The one bright planet in the evening sky, Mercury, will pass between us and the Sun this Saturday to join the rest of the naked-eye planets in the morning sky. So that’s where the planet action is. At 5:15 am tomorrow, the planets will be spread out from brilliant Venus low in the east to Saturn higher in the southeast. Venus may be missed at that time, but may be up sufficiently by 5:30. To the right of Venus is the quite bright Jupiter. Farther right will be the dimmest of the 4, Mars, which is closing on Jupiter. The two will seem to pass each other on the 29th of this month. All will be in line, sloping to the upper right. They are still quite a sight to behold in the morning twilight.

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

Annotated Moon animation

The Moon as it might appear in binoculars or a small telescope tomorrow morning at 1:30 May 19, 2022. Created using Stellarium, GIMP and LibreOffice.

The morning planet parade

The morning planet parade is widening as Venus is moving away from Jupiter and toward the Sun. Mars is approaching Jupiter and will catch up to it on the 29th. These are shown at 5:15 am, or about an hour before sunrise tomorrow morning, May 19, 2022. Click on the image to enlarge it. Created using Stellarium.

Telescopic views of Venus, Saturn and Jupiter

Views of Venus, Jupiter, and Saturn (north up) as they would be seen in a small telescope, with the same magnification, tomorrow morning at 5:15 am, May 19, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 14.73″, 73.9% illuminated; Saturn 16.99″, its rings 39.59″; Jupiter 36.17″. Mars is not shown, its apparent diameter is 6.14″ and is 88.1% illuminated. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on May 18, 2022. The night ends on the left with sunrise on the 19th. Notice that all the naked-eye planets except Mercury are in the morning sky now. Click on the image to enlarge it. Created using my LookingUp program.

05/16/2022 – Ephemeris – A peek at the monster at the center of the Milky Way

May 17, 2022 Comments off

This is Ephemeris for Tuesday, May 17th. Today the Sun will be up for 14 hours and 54 minutes, setting at 9:06, and it will rise tomorrow at 6:11. The Moon, 1 day past full, will rise at 11:33 this evening.

This past Thursday the Event Horizon Telescope Collaboration released an image of the black hole at the center of the Milky Way, 27,000 light years away In the direction of the constellation of Sagittarius, which is currently visible low in the south in the morning hours. How they got the image is too complex to explain here, not that I know how they did it. It appears as a fuzzy donut with three bright areas around the edges. The dark center is the shadow of the black hole, because no light can escape it, plus it severely bends any light that comes near it. The light we’re seeing it is in millimeter microwaves, rather than the nanometer wavelengths of visible light. Part of the fuzziness of the image is due to the motion of the material surrounding it.

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

Milky Way Black Hole

This is the image released May 12, 2022 by the Event Horizon Telescope Collaboration.

M87 compared to Sagittarius A*

M87* size compared to Sagittarius A*. The size of a black hole is directly related to its mass. The asterisk * is pronounced “Star”. Credit: Event Horizon Telescope Collaboration.

It looks like I’ll have to update my presentation, What Lurks in the Center of the Milky Way? Astronomers were already sure it was a black hole, but the donut appearance of Sagittarius A* clinched it.

Off topic

Lunar eclipse shortly after the partial eclipse began

Last night’s (May 15/16) lunar eclipse, shortly after the partial eclipse began behind clouds. I often checked until totality, but it seems to get worse. I may have missed brief clearings. When I got up, it was clear… Figures.

05/16/2022 – Ephemeris – More eclipses in our future

May 16, 2022 Comments off

This is Ephemeris for Monday, May 16th. Today the Sun will be up for 14 hours and 52 minutes, setting at 9:05, and it will rise tomorrow at 6:12. The Moon, at full today, will rise at 10:13 this evening.

Last night’s eclipse was the only eclipse that was visible in our area this year. However, in the next two years we will have a chance, weather permitting, to see two partial solar eclipses, the second of which will be even better than the partial solar eclipse seen here in August 2017. On October 14, 2023, there will be an annular eclipse. An annular eclipse is where the Moon is too far away to completely cover the face of the Sun. It leaves a ring of bright sun around the Moon. The technical term for a ring like that is annulus. The path of annularity will run from Oregon to Texas. For the Grand Traverse Area of Michigan, the Moon will cover less than half the face of the Sun. On April 8, 2024, the total eclipse path will run from Texas to Maine and just nip the Southeast corner of Michigan covering, for us in the Grand Traverse Area, about 85 percent of the Sun.

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

Path across US of Ocober 14 2023 annular solar eclipse

The areas where the October 14, 2023 solar eclipse can be seen are bounded by the outer green lines. The path where the annular part of the eclipse is visible is denoted by the triple green lines. Plotted on Google Earth using a file created by Occult4 software from the International Occultation Timing Association.

Path across the US of the April 8 2024 total solar eclipse

The areas across the U.S. where the April 8, 2024 solar eclipse can be seen are bounded by the outer green lines. The path where the total part of the eclipse is visible is denoted by the triple green lines. Plotted on Google Earth using a file created by Occult4 software from the International Occultation Timing Association.

05/13/2022 – Ephemeris – Remember, there is going to be an eclipse of the Moon late Sunday night!

May 13, 2022 Comments off

This is Bob Moler with Ephemeris for Friday, May 13th. Today the Sun will be up for 14 hours and 45 minutes, setting at 9:02, and it will rise tomorrow at 6:15. The Moon, 3 days before full, will set at 5:28 tomorrow morning.

There is going to be an eclipse of the Moon running from late Sunday night into the early Monday morning hours. That’s the night of May 15/16. By 10:30 pm, there will appear a noticeable “bite” out of the lower left edge of the Moon as it enters the Earth’s inner shadow, called the umbra. The shadow will creep across the Moon for the next hour. And by 11:30 the Moon is completely immersed in the Earth’s inner shadow. By now, one will notice that the shadow is not completely black. The Moon usually has a dim reddish hue caused by all the simultaneous sunrises and sunsets around the Earth. This is the total phase of the eclipse, which will last until almost 1 am. The Moon will slowly exit the inner shadow by 2 am.

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

05-16-22 Lunar eclipse diagram2

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. From Five Millennium Canon of Lunar Eclipses (Espenak & Meeus) NASA, with additions.

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 10 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).
Surveyor3 solar eclipse

Solar eclipse by the Earth as photographed by Surveyor 3, which had landed on the Moon, April 24, 1967. The Earth was seeing a lunar eclipse at the time. Light seeps into the Earth’s shadow at the Moon’s distance due to atmospheric refraction. The amount of light depends on the atmospheric conditions at the time. Great volcanic eruptions can cause a very dark, nearly invisible, eclipsed Moon. Credit: NASA.

Update 7:30 pm, May 15th

In note for P1 time: Expected actual visibility of penumbral shadow is changed to 10 pm (2 hr UT).

05/12/2022 – Ephemeris – There will be a total eclipse of the Moon this Sunday night/Monday morning

May 12, 2022 Comments off

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

Lunar Eclipse Geometry

How lunar eclipses occur. Credit NASA/Fred Espenak.

05-16-22 Lunar eclipse diagram2

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).

05/11/2022 – Ephemeris – Let’s search for the naked-eye planets for this week

May 11, 2022 Comments off

This is Bob Moler with Ephemeris for Wednesday, May 11th. Today the Sun will be up for 14 hours and 40 minutes, setting at 8:59, and it will rise tomorrow at 6:18. The Moon, 3 days past first quarter, will set at 4:45 tomorrow morning.

Let’s search for the naked-eye planets for this week. The one bright planet in the evening sky, Mercury, is now too dim and close to the Sun to be seen, so the only planet action is in the morning sky where the other 4 naked-eye planets are. At 5:15 am tomorrow the planets will be spread out low from the east to southeast with brilliant Venus lowest and due east to Saturn almost exactly in the southeast. Venus may be missed at that time, but may be up sufficiently by 5:30. To the right of Venus is the quite bright Jupiter. Farther right will be the dimmest of the four, Mars. Farther to the right will be Saturn. All will be in A sloping to the upper right. They are still quite a sight to behold in the morning twilight.

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

Annotated Binocular Moon

Animated annotated Binocular Moon for this evening, May 11, 2022. Created using Virtual Moon Atlas, GIMP and LibreOffice.

Translations

Mare Crisium – Sea of Crises
Mare Fecunditatis – Sea of Fertility
Mare Frigoris – Sea of Cold
Mare Imbrium – Sea of Showers
Mare Nectaris – Sea of Nectar
Mare Nubium – Sea of Clouds
Mare Serenitatis – Sea of Serenity
Mare Tranquillitatis – Sea of Tranquility
Mare Vaporum – Sea of Vapors
Sinus Iridium – Bay of Rainbows
Sinus Medii – Bay of the Center

Note that Mare is pronounced Mar-é

Morning planet parade

The morning planet parade is widening as Venus is moving away from Jupiter, and Mars is approaching Jupiter. These are shown at 5:15 am, or about an hour before sunrise tomorrow morning, May 12, 2022. Created using Stellarium.

Telescopic views of Venus, Saturn and Jupiter

Views of Venus, Jupiter, and Saturn (north up) as they would be seen in a small telescope, with the same magnification, tomorrow morning at 5:15 am, May 12, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 15.42″, 71.6% illuminated; Saturn 16.79″, its rings 39.12″; Jupiter 35.60″. Mars is not shown, its apparent diameter is 5.99″ and is 88.6% illuminated. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on May 11, 2022. The night ends on the left with sunrise on the 12th. Notice that all the naked-eye planets except Mercury are in the morning sky now. Click on the image to enlarge it. Created using my LookingUp program.

05/10/2022 – Ephemeris – Event Horizon Telescope Collaboration will announce “groundbreaking Milky Way results” on Thursday

May 10, 2022 Comments off

This is Ephemeris for Tuesday, May 10th. Today the Sun will be up for 14 hours and 38 minutes, setting at 8:58, and it will rise tomorrow at 6:19. The Moon, 2 days past first quarter, will set at 4:25 tomorrow morning.

This Thursday, May 12th at 13:00 UT (9 am our time EDT) the Event Horizon Telescope Collaboration will announce “groundbreaking Milky Way results.” Their words. Their first groundbreaking result came in three years ago with the release of an image of the billion solar mass black hole in the heart of the giant galaxy M 87 over 50 million light years away. Beforehand, I was expecting the results to concern a more nearby black hole called Sagittarius A* (pronounced Sagittarius A Star) at the center of our galaxy, only 25 to 27 thousand light years away. That turned out to be much more difficult than the one in M 87, due to the amount of dust and gas in the way. So maybe this time they have done it. We’ll all find out this Thursday.

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

Black hole in M87

The first image of the black hole in M87. Credit Event Horizon Telescope.

The Event Horizon Telescope isn’t a single telescope. But millimeter wavelength radio telescopes spaced out to use the diameter of the Earth as its simulated aperture. The ability to resolve tiny objects at great distances depends on the wavelength of the radiation and the size of the telescope aperture. So the smaller the wavelength and the larger the aperture, the greater the resolution of the telescope or array.

The observation of all the telescopes must be performed at the same time, recording the observations on terabyte magnetic disks. The disks are brought to a single location for processing together to actually produce the image, which takes a while.

Event Horizon Telescope

Event Horizon Telescope component radio telescopes. Credits: © APEX, IRAM, G. Narayanan, J. McMahon, JCMT/JAC, S. Hostler, D. Harvey, ESO/C. Malin.