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06/27/2022 – Ephemeris – Finding the Summer Triangle

June 27, 2022 Leave a comment

This is Ephemeris for Monday, June 27th. Today the Sun will be up for 15 hours and 33 minutes, setting at 9:32, and it will rise tomorrow at 5:59. The Moon, 1 day before new, will rise at 5:13 tomorrow morning.

We’re nearly a week into summer, and the asterism or informal constellation called the Summer Triangle can be seen rising in the east as it gets dark. Highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram nearby. The second star of the triangle is Deneb, in Cygnus the swan, lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years, while Deneb may be a whopping 2,600 light years away. One light year is 6 trillion miles (9 trillion kilometers).

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

Summer Triangle finder animation

The Summer Triangle finder animation showing first the unlabeled sky, Then the Summer Triangle with the stars labeled, then the constellations of those stars. Created using Stellarium and GIMP.

06/24/2022 – Ephemeris – Finding the greatest celestial hero: Hercules

June 24, 2022 Leave a comment

This is Ephemeris for Friday, June 24th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, halfway from last quarter to new, will rise at 3:31 tomorrow morning.

Orion, the hard luck mythical Greek hunter, gets a splashy constellation in the winter sky, but the greatest hero of all, Hercules, gets a dim group of stars on the border between the spring and summer stars. At 11 p.m. Hercules is high in the southeast. It is located right of the bright star Vega, in the east. Hercules’ central feature is a keystone shaped box of stars, called, of course, the Keystone of Hercules tilted to the left, which represents the old boy’s shorts. From the top and left corner stars extend lines of stars that are his legs, from the bottom and right stars, the rest of his torso and arms extend. So in one final indignity, he’s upside down in our sky. For those with a telescope, Hercules contains the beautiful globular star cluster Messier 13.

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

Hercules finder

Hercules animation showing neighboring stars at 11 p.m. for mid-June. Click on image to enlarge. Created using Stellarium.

Hercules globular star cluster finder

Hercules with all the stars visible in binoculars and its two globular star clusters: M13 and M92. M13 is almost bright enough to be spotted with the naked eye. It is easily visible in binoculars as a tiny fuzzy spot. It takes a telescope with an aperture of 6 – 8″ or 150 – 200 mm to begin to see some individual stars. M92 is dimmer and harder to resolve. Created using Cartes du Ciel (Sky Charts).

M 13

M 13, the Great Globular Star Cluster in Hercules. Credit: Scott Anttila.

06/23/2022 – Ephemeris – Corona Borealis, the Northern Crown

June 23, 2022 Leave a comment

This is Ephemeris for Thursday, June 23rd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:58. The Moon, 3 days past last quarter, will rise at 3:08 tomorrow morning.

High in the south at 11 this evening can be seen a small nearly circular constellation of Corona Borealis, the Northern Crown. It is just left of Boötes, the kite shaped constellation off the handle of the Big Dipper. According to Greek myth, the crown was given by the gods to the princess Ariadne, daughter of King Minos of Crete. The crown is more like a tiara with the bright star Alphecca at the front. To the Anishinaabe people, who are native to our region, it is the Sweat Lodge. Part of what we call Hercules next to it is the Exhausted Bather, who is lying on the ground after the ceremony. The seven stones that are heated for the Sweat Lodge ceremony are the Pleiades, now close to Venus 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

Corona Borealis and Sweat Lodge finder animation

Corona Borealis and Sweat Lodge finder animation. Looking high in the south at 11 pm, June 23rd. The tail of Ursa Major or the handle of the Big Dipper is in the upper right. Created using Stellarium and GIMP. Both star lore images are embedded in Stellarium. The Anishinaabe images are embedded in Stellarium and is from Ojibwe Giizhig Anung Masinaaigan – Ojibiwe Sky Star Map created by A. Lee, W. Wilson, and C. Gawboy.

05/20/2022 – Ephemeris – Spring constellations: Corvus the crow

May 20, 2022 Comments off

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 Comments off

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.

05/03/2022 – Ephemeris – Regulus, the “Little King Star”

May 3, 2022 Comments off

This is Bob Moler with Ephemeris for Tuesday, May 3rd. Today the Sun will be up for 14 hours and 20 minutes, setting at 8:50, and it will rise tomorrow at 6:28. The Moon, 3 days past new, will set at 12:05 tomorrow morning.

Fairly high in the south-southwest at 10 p.m. is a pattern of stars that’s in the shape of a backward question mark. This informal star group or asterism is also called the sickle. It is the head and mane of the official zodiacal constellation of Leo the lion. To the left is a triangle of stars is his hind end. The bright star at the bottom of the question mark, or end of the sickle’s handle is Regulus, the “Little King Star”, alluding to the lion’s status as the king of the jungle. Regulus is about 79 light years away and is a 4 star system that exists as two star pairs. The bright star Regulus itself and a companion too close to be imaged directly in telescopes, and a nearby pair of dim stars make up the system. The Moon often passes in front of Regulus, since it’s close to the ecliptic. These occultations, as they are called, will occur monthly for a year and a half starting July

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

Finder chart for Leo and Regulus

Animated finder chart for Leo and Regulus for early May at 10 pm or an hour after sunset. The orange line that appears is the ecliptic, the path of the Sun in the sky. The path of the Moon is tilted by about 5 degrees to that path. The paths cross at points called nodes. The nodes move slowly westward in an 18.6-year cycle called the regression of the nodes. Occultations of Regulus by the Moon occur during two periods in that cycle. The next period where occultations of Regulus will occur monthly from July 2025 to January 2027. Created using Stellarium and GIMP.

Occultations are like solar eclipses in that they can only be seen from a limited area. That area will shift southward during that period. Of the 21 occultations in that period, only 2 will be visible from the United States: February 3rd, and April 26th 2026.

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

04/19/2022 – 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).

03/28/2022 – Ephemeris – Finding the Great Bear

March 28, 2022 Comments off

This is Ephemeris for Monday, March 28th. Today the Sun will be up for 12 hours and 34 minutes, setting at 8:05, and it will rise tomorrow at 7:29. The Moon, 3 days past last quarter, will rise at 6:47 tomorrow morning.

The Big Dipper is now reaching for the zenith in the northeast at 10 p.m. The seven bright stars are second to Orion in the west as the seven brightest stars in a constellation. If you looked up a list of constellations, you’d find that the Big Dipper isn’t there. Ursa Major or the Great Bear is the constellation of which the Big Dipper is a part. The seven bright stars of the dipper are the rump and long tail of this constellation. The rest of the bear, including his head and legs, are delineated by dimmer stars. An anatomical problem is its long tail, which was drawn in by the ancients of the old world. Their explanation was that a god had grabbed the bear’s stubby tail, whirled the bear around his head, and threw it into the sky, thus stretching its tail.

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

Great Bear Finder animation

The Great Bear (Ursa Major) finder animation. It shows the stars only, then the Big Dipper, Then the lines of the constellations Ursa Major and Ursa Minor (Lesser Bear and Little Dipper) as a bonus, and finally the constellation artwork. The orientation is for about 9:30 pm on the latter days of March. We are looking high in the northeast. In Northern Michigan, the bear’s front paw is near the zenith at that time. Created using Stellarium and GIMP.

03/21/2022 – Ephemeris – Finding the celestial lion

March 21, 2022 Comments off

This is Ephemeris for Monday, March 21st. Today the Sun will be up for 12 hours and 12 minutes, setting at 7:56, and it will rise tomorrow at 7:42. The Moon, 3 days past full, will rise at 12:15 tomorrow morning.

At 10 p.m. the spring constellation of Leo the lion will be fairly high in the southeast. It can be found by locating the Big Dipper high in the northeast and imagining that a hole were drilled in the bowl to let the water leak out. It would drip on the back of this giant cat. The Lion is standing or lying facing westward. His head and mane are seen in the stars as a backwards question mark. This group of stars is also called the Sickle. The bright star Regulus is at the bottom, the dot at the bottom of the question mark. A triangle of stars, to the left of Regulus, is the lion’s haunches. Leo contains some nice galaxies visible in moderate sized telescopes. The stars in Leo’s part of the sky are fewer than those in the winter sky.

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

Leaky Dipper drips on Leo

Leaky Big Dipper drips on Leo. The positions in the sky are for 10 pm local time, or about 2 hours after sunset. The little distorted cross at the top of the image marks the zenith. Look high in the east and southeast to see these stars. Created using my LookingUp program, GIMP and LibreOffice.