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04/28/2022 – Ephemeris – The story of Arcas and Callisto

April 28, 2022 Comments off

This is Bob Moler with Ephemeris for Thursday, April 28th. Today the Sun will be up for 14 hours and 6 minutes, setting at 8:44, and it will rise tomorrow at 6:35. The Moon, 2 days before new, will rise at 6:16 tomorrow morning.

Appearing in the eastern sky at 10 p.m. tonight is the kite shaped constellation of Boötes the herdsman. The bright star Arcturus is at the bottom of the kite which is horizontal to the left, pointed to by the arc of the handle of the Big Dipper, higher in the east. The Big Dipper is the hind end of the constellation Ursa Major, the Great Bear. In one story, Boötes represents a young hunter named Arcas, son of Callisto, a beautiful young woman who had the misfortune of being loved by god Zeus. Zeus’ wife, Hera, found out about the affair, and since she couldn’t punish Zeus, turned the poor woman into a bear. Arcas, many years later, unaware of why his mother disappeared, was about to kill the bear when Zeus intervened and placed them both in the sky, where he continues to chase her across the sky nightly.

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

Arcas and Callisto

Boötes and Ursa Major aka Arcas chasing Callisto around the pole of the sky. Created using Stellarium.

Arcas and Callisto woodcut

Arcas about to slay the bear by the 17th century artist Baur. Source: University of Virginia Electronic Text Center

04/27/2022 – Ephemeris – Let’s search for the naked-eye planets for this week

April 27, 2022 Comments off

This is Bob Moler with Ephemeris for Wednesday, April 27th. Today the Sun will be up for 14 hours and 4 minutes, setting at 8:42, and it will rise tomorrow at 6:37. The Moon, 3 days before new, will rise at 5:56 tomorrow morning.

Let’s search for the naked-eye planets for this week. There is one bright planet in the evening sky. Mercury may be spotted around and after 9:30 this evening very low in the west-northwest and be visible for the next hour or so before it sets at 10:43 pm. After that, the planet action shifts to the morning sky. The other 4 naked-eye planets are there. By 5:45 am, the planets will be spread out low from the east to southeast with brilliant Venus closer than ever to Jupiter, lowest in the east. Dim Mars will be to the right and a bit above Venus, while brighter Saturn will be right and above Mars. Saturn will rise tomorrow at 4 am, with Mars following at 4:40. Venus will rise at 5:10 tomorrow morning, followed by Jupiter four minutes later.

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

Mercury and bright winter stars in evening twilight

Mercury and bright winter stars in evening twilight at 9:30 tonight, or about 45 minutes after sunset tonight, April 27, 2022. It might take binoculars to spot the stars of Orion and Taurus, and Mercury itself, which is fading, becoming a crescent. Click on the image to enlarge it. Created using Stellarium.

The morning planet parade

The morning planet parade at 5:45 am or about 50 minutes before sunrise tomorrow, April 28, 2022. Venus will overtake Jupiter during the day, Saturday the 30th. Created using Stellarium.

Jupiter and Venus in binoculars

Jupiter and Venus in as they might be seen in binoculars, Saturday morning, April 30, 2022. The difference in brightness of Venus compared to Jupiter will be much greater than seen here. The planets will be about a half a degree apart, or about the width of the Moon. The image shows two satellites of Jupiter, Ganymede to the lower left of Jupiter and Callisto to the upper right. A third satellite, Io, is close to the upper right, within the enlarged Jupiter image. Europa is either behind the planet or in its shadow. Sunday morning, Jupiter will be on the other side of Venus, and a bit farther away. 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 5:45 am, April 28, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 16.78″, 67.4% illuminated; Saturn 16.47″, its rings 38.35″; Jupiter 34.76″. Mars is not shown, its apparent diameter is 5.74″ and is 89.5% illuminated. Mercury, in the evening, has an apparent diameter of 8.05″, and it’s 35.6% 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 April 27, 2022. The night ends on the left with sunrise on the 28th. 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.

04/26/2022 – Ephemeris – Tomorrow is the Moon’s final stop in passing the parade of morning planets

April 26, 2022 Comments off

This is Bob Moler with Ephemeris for Tuesday, April 26th. Today the Sun will be up for 14 hours and 1 minute, setting at 8:41, and it will rise tomorrow at 6:38. The Moon, 3 days past last quarter, will rise at 5:37 tomorrow morning.

Also, tomorrow morning, the Moon will conclude its sweep under the four bright planets of the morning sky by being seen below the left-most and lowest of the four, Jupiter. With nearby Venus, it makes a small right triangle The other planets in order to the right of Jupiter are Venus, Mars and finally Saturn. Jupiter and Venus are appearing to get closer to each other every day now. They will cross paths in conjunction this Saturday. Venus is slowly retreating back and around behind the Sun. Jupiter now appears to be moving away from the Sun. Both, however, are still moving eastward against the stars, it’s just that Venus is moving faster. Next month, when the Moon passes by these planets, they will be a different order.

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 from Sunday to Wednesday mornings 4/24 to 4/27/2022

The Moon passing the morning planets from Sunday to Wednesday mornings 4/24 to 4/27/2022. Note also the approach of Jupiter and Venus. Their paths will cross on Saturday, 4/30/2022. Click on the image to enlarge it. Created using Stellarium and GIMP.

04/25/2022 – Ephemeris – The moon is passing the morning planet parade

April 25, 2022 Comments off

This is Bob Moler with Ephemeris for Monday, April 25th. Today the Sun will be up for 13 hours and 58 minutes, setting at 8:40, and it will rise tomorrow at 6:40. The Moon, 2 days past last quarter, will rise at 5:16 tomorrow morning.

Over this and the next couple of mornings, the waning crescent Moon will be passing the four morning planets. This morning it was below and between Saturn and Mars. Tomorrow morning, the Moon will be between and below Mars and Venus. Wednesday morning the Moon, Venus and Jupiter will make a nice right triangle with Jupiter above and a bit left of the Moon and Venus will appear above and a bit to the right of it. There’s some motion between Venus and Jupiter. While both are traveling eastward when comparing them to the stars, Venus is moving eastward faster, and is moving toward the Sun in our sky. Jupiter is moving away from the Sun from our vantage point. They will cross paths on Saturday.

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 from Sunday to Wednesday mornings 4/24 to 4/27/2022

The Moon passing the morning planets from Sunday to Wednesday mornings 4/24 to 4/27/2022. Note also the approach of Jupiter and Venus. Their paths will cross on Saturday, 4/30/2022. Click on the image to enlarge it. Created using Stellarium and GIMP.

04/21/2022 – Ephemeris – The Lyrid Meteor Shower reaches its peak tomorrow afternoon

April 21, 2022 Comments off

This is Bob Moler with Ephemeris for Thursday, April 21st. Today the Sun will be up for 13 hours and 47 minutes, setting at 8:35, and it will rise tomorrow at 6:46. The Moon, 2 days before last quarter, will rise at 2:54 tomorrow morning.

The second major meteor shower this year will reach its peak tomorrow afternoon around 2 pm (~19h UT). One of the best times to see it will be tonight from about 10 pm to near 3 am when the Moon rises. The other is tomorrow night. The meteor shower is called the Lyrids, because they seem to come from near the constellation Lyra the harp and the bright star Vega. At 10 p.m. Vega is the brightest star low in the northeastern sky. By 3 a.m. Vega will be high in the east. The radiant of the meteors is to the west of Vega, between Lyra and the dim constellation of Hercules. The most meteors will be visible just before the Moon begins to brighten the sky before 3 a.m. Though a major shower, the peak hourly rate is expected to be less than 20 meteors an hour.

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

Lyrid radiant at 11 pm

The Lyrid radiant at 11 pm, looking to the east-northeast. The meteors will be seen all over the sky, but their tracks can be traced back to the radiant point, like the parallel rails of a train track recede to a point in the distance. Click on the image to enlarge it. Created using Stellarium.

Lyrid radiant at 3 am

The Lyrid radiant at 3 am, looking in this all-sky view. Vega will be very high in the east and Hercules will be almost overhead. The meteors will be seen all over the sky, but their tracks can be traced back to the radiant point, like the parallel rails of a train track recede to a point in the distance. There are two other minor meteor showers happening at the same time, though neither is at peak, providing only a few meteors per hour. Click on the image to enlarge it. Created using Stellarium.

04/20/2022 – Ephemeris – Let’s search for the naked-eye planets for this week

April 20, 2022 Comments off

This is Ephemeris for Wednesday, April 20th. Today the Sun will be up for 13 hours and 44 minutes, setting at 8:34, and it will rise tomorrow at 6:48. The Moon, 3 days before last quarter, will rise at 1:51 tomorrow morning.

Let’s search for the naked-eye planets for this week. There is one bright planet in the evening sky. Mercury may be spotted around and after 9:15 this evening very low in the west-northwest and be visible for the next half hour or so. After that, the planet action shifts to the morning sky. The other 4 naked-eye planets are there. By 6 am, the planets will be spread out low from the east to southeast with brilliant Venus moving closer to Jupiter, lowest in the east. Dim Mars will be to the right and a bit above Venus, while brighter Saturn will be right and above Mars. Saturn will rise tomorrow at 4:27 am, with Mars following at 4:55. Venus will rise at 5:19 tomorrow morning, followed by Jupiter at 5:39 am. The Moon will be in the south at 6 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

Mercury in the evening

Mercury in the evening at 9:15, or about 40 minutes after sunset tonight, April 20, 2022. Created using Stellarium.

Annotated Binocular Moon

Annotated Binocular Moon. What the Moon might look like tomorrow morning, April 21, 2022. Created using Stellarium, GIMP and LibreOffice.

Translations

Mare Frigoris – Sea of Cold
Mare Humorum – Sea of Moisture
Mare Imbrium – Sea of Showers
Mare Nubium – Sea of Clouds
Mare Serenitatis – Sea of Serenity
Oceanus Procellarum – Ocean of Storms

Note that Mare is pronounced Mar-é

Parade of the morning planets

Parade of the morning planets at 6 am or about 45 minutes before sunrise tomorrow, April 21, 2022. Created using Stellarium.

Telescopic views of Venus, Saturn and Jupiter

Views of Venus, Saturn, and Jupiter (north up) as they would be seen in a small telescope, with the same magnification, tomorrow morning at 6:00 am, April 21, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 18.01″, 64.0% illuminated; Saturn 16.24″, its rings 37.82″; Jupiter 34.24″. Mars is not shown, its apparent diameter is 5.56″ and is 90.2% illuminated. The moons of Jupiter and Saturn may not be visible in twilight. Io transiting the face of Jupiter definitely will not be visible. Jupiter is shown here much dimmer compared to its moons than it actually is. 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 April 20, 2022. The night ends on the left with sunrise on the 21st. Notice that all the naked-eye planets are in the morning sky now, with the Moon still hanging out in the evening sky. Click on the image to enlarge it. Created using my LookingUp program.

04/19/2022 – Ephemeris – A constellation memorializing a real person

April 19, 2022 Comments off

This is Ephemeris for Tuesday, April 19th. Today the Sun will be up for 13 hours and 41 minutes, setting at 8:32, and it will rise tomorrow at 6:49. The Moon, 3 days past full, will rise at 12:37 tomorrow morning.

High in the southeast at 10 p.m. is a tiny and faint constellation of Coma Berenices, or Berenice’s Hair. In it are lots of faint stars arrayed to look like several strands of hair to the naked eye. The whole group will fit in the field of a pair of binoculars, which will also show many more stars. The story behind it was that Berenice was a real Queen of Egypt, whose husband was away at war. This was in the days when the Greeks ruled Egypt after Alexander conquered it. She offered her golden tresses to the gods for the king’s safe return. The hair, was placed in a temple. However, the offering disappeared when the king returned. Ever since then, the constellation of Coma Berenices has been seen to commemorate the queen’s sacrifice.

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

Coma Berinices

Coma Berenices and neighboring constellations at 10 p.m. in mid-April. Note that only the upper right star of the upside down L shape actually belongs to the cluster. Click on the image to enlarge it. Created using Stellarium.

Coma Berenices

Approximate 7 power binocular field of view (FOV) of the Coma Berenices Cluster. Created using Cartes du Ciel (Sky Charts).

04/18/2022 – Ephemeris – Arcturus, the fourth-brightest nighttime star*

April 18, 2022 Comments off

This is Ephemeris for Monday, April 18th. Today the Sun will be up for 13 hours and 38 minutes, setting at 8:31, and it will rise tomorrow at 6:51. The Moon, 2 days past full, will rise at 11:17 this evening.

The fourth-brightest nighttime star* is now up in the east these evenings. It is Arcturus, a bright star with an orange hue. It can be found otherwise by finding the Big Dipper and tracing out and extending the curve of the handle and saying the phrase “Follow the arc of the handle to Arcturus”, to remember the name of the star and how to find it. Arcturus is about 37 light years from us and is moving quite rapidly across the sky, compared to most stars, but one would not notice it to the naked eye in one’s lifetime. Arcturus is slightly more massive than our Sun, and about 7 billion years old, and is entering its red giant stage of life after using all the hydrogen fuel in its core. Our Sun, being slightly less massive, will survive on hydrogen a bit longer.

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.

*Or 5th brightest star, depending on which list you look at. Arcturus and Vega, which is just above the horizon in the northeast at 10 pm, are nearly the same brightness, however Vega is white while Arcturus is orange, making brightness comparisons difficult visually. Stellarium, however, reports Vega is a slightly brighter magnitude 0.00, while Arcturus is 0.15. My older lists say Arcturus is the 4th brightest star. I’m an older guy, so I’m sticking with it.

Addendum

How to find Arcturus nearly a month into spring. Arcturus is in the east in the evening. The Big Dipper is high in the northeast standing on its handle. To find and remember the name of this star, simply follow the arc of the handle to Arcturus. Created using Stellarium and GIMP.

I’ll have more tidbits about this remarkable star throughout the spring and summer. Can’t wait? Search for Arcturus on this blog.

04/06/2022 – Ephemeris – Let’s search for the naked-eye planets for this week

April 6, 2022 Comments off

This is Bob Moler with Ephemeris for Wednesday, April 6th. Today the Sun will be up for 13 hours and 2 minutes, setting at 8:16, and it will rise tomorrow at 7:12. The Moon, 3 days before first quarter, will set at 2:16 tomorrow morning.

Let’s search for the naked-eye planets for this week. There is one bright planet in the evening sky, but too close to the Sun to be seen. Mercury passed behind the Sun last Saturday and will be visible later this month, so the planet action still shifts to the morning sky. The other 4 naked-eye planets are there, though Jupiter is too close to the Sun to be seen. Late winter and early spring mornings aren’t the best for spotting planets close to the Sun, since they tend to lie low in the southeastern sky. Venus, Mars, and Saturn will rise within 16 minutes of each other by 5:35. By 6:30, they will be low in the east-southeast with dim Saturn to the right and a bit above Venus, and much dimmer Mars to the left and below Saturn.

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 crescent Moon

Annotated crescent Moon animation of the Moon tonight, April 6, 2022. The annotations are the official names in Latin of the seas of Tranquility, Crises, Nectar, and Fertility. Created using Stellarium.

Venus, Mars and Saturn in the morning

Venus, Mars and Saturn as they might be seen around 6:30 tomorrow morning, April 7, 2022. Created using Stellarium.

Telescopic views of Venus and Saturn

Views of Venus and Saturn (north up) as they would be seen in a small telescope, with the same magnification, tomorrow morning at 6:30 am, April 7, 2022. I do not show planets less than 10 seconds of arc in diameter. Apparent diameters: Venus 20.38″, 58.2% illuminated; Saturn 15.92″, its rings 37.08″. Mars is not shown, its apparent diameter is 5.30″ and is 91.2% 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 April 6, 2022. The night ends on the left with sunrise on the 7th. Notice that all the naked-eye planets are in the morning sky now, with the Moon still hanging out in the evening sky. Click on the image to enlarge it. Created using my LookingUp program.

04/04/2022 – Ephemeris – Two apparent planetary encounters tonight and tomorrow morning

April 4, 2022 Comments off

This is Ephemeris for Monday, April 4th. Today the Sun will be up for 12 hours and 56 minutes, setting at 8:14, and it will rise tomorrow at 7:16. The Moon, 3 days past new, will set at 12:10 tomorrow morning. | We have action at both end of the night tonight. This evening the Pleiades, or Seven Sisters star cluster, will be seen just above and right of the three-day old crescent Moon. The cluster will be at the one o’clock position from the Moon at 9 pm. At the other side of night, at 6:30 tomorrow morning, Venus will be shining brilliantly in the east-southeast and the planets Mars and Saturn will be very close together. This type of appearance is called a conjunction. Mars will appear about three-quarters of a moon diameter below and left of the slightly brighter Saturn. Mars is getting slowly brighter as the Earth creeps up on it, to overtake it this December. It’s currently 165 million miles (266 million kilometers) away.

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 and the Pleiades and Hyades tonight at 9 pm EDT, April 4, 2022. The Moon appears near the stepsister star clusters tonight. In Greek mythology, these two star clusters were indeed stepsisters, fathered by the god Atlas with different mothers. Created using Stellarium with additional captions in LibreOffice.

Saturn-Mars conjunction

A Saturn-Mars conjunction with brilliant Venus nearby as it might look like tomorrow morning, April 5, 2022. Created using Stellarium with labels added in LibreOffice.