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Archive for the ‘Asterism’ Category

02/11/2021 – Ephemeris – The Winter Triangle

February 11, 2021 Comments off

This is Ephemeris for Thursday, February 11th. Today the Sun will be up for 10 hours and 17 minutes, setting at 6:06, and it will rise tomorrow at 7:47. The Moon is new today, and won’t be visible.

I usually talk about the Winter Circle of bright stars, but some other astronomers talk about the Winter Triangle. The stars involved are Betelgeuse in the hunter Orion, Sirius in Canis Major, Orion’s large hunting dog, and Procyon in Canis Minor, his other small hunting dog. These three stars enclose a rather blank piece of sky with the faint Milky Way running through it and the almost invisible constellation of Monoceros the unicorn. The Summer Triangle has three bright stars with no other close competition. The Winter Triangle has four other bright stars near it. Any three of these would make a nice triangle. One of these constellations Canis Minor is tiny, with Procyon and one other star. It makes me think of a dachshund, or maybe, if I’m hungry, a hot dog.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Winter triangle finder animation

Winter Triangle finder animation. It shows the star field, named first magnitude stars, then their constellations, then the Winter Triangle and constellations of the three stars. Click on the image to enlarge. Created using Stellarium and GIMP.

01/14/2021 – Ephemeris – The constellation of Auriga the charioteer

January 14, 2021 Comments off

This is Bob Moler with Ephemeris for Thursday, January 14th. Today the Sun will be up for 9 hours and 10 minutes, setting at 5:27, and it will rise tomorrow at 8:16. The Moon, 1 day past new, will set at 7:06 this evening.

The constellation Auriga the charioteer is nearly overhead at 9 p.m. It is a pentagon of stars, with the brilliant star Capella at one of its corners. Capella represents a she-goat he’s carrying. A narrow triangle of stars nearby Capella are her kids. The Kids is an informal constellation or asterism. Within and near that pentagon, binoculars and telescopes will find several star clusters, groups of hundreds of stars born in the clump we still see them in. These star clusters will appear as fuzzy spots in binoculars. One called M38 is near the center of the pentagon. Another, M36 is to the east of it. Still another star cluster, M37, is farther east, just outside the pentagon. The M designations come from Charles Messier who 250 years ago ran into them while looking for comets.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Auriga finder animation

Auriga finder animation showing the Kids, nearby stars including Aldebaran and the sideways V shape of the Hyades (unlabeled) of Taurus the bull and the Pleiades AKA M 45. Created using Stellarium and GIMP.

11/17/2020 – Ephemeris – The Pleiades in legends from different cultures

November 17, 2020 Comments off

This is Ephemeris for Tuesday, November 17th. Today the Sun will be up for 9 hours and 29 minutes, setting at 5:12, and it will rise tomorrow at 7:44. The Moon, 2 days past new, will set at 7:23 this evening.

Let’s look at how some other cultures saw the Pleiades, the star cluster that is seen in the eastern sky these evenings. To the Anishinaabe native peoples around here the Pleiades is the “Hole in the Sky” or the seven stones that are heated for the sweat lodge ceremony. To the Kiowa these were sister stars that had been whisked into the sky from the top of Devils Tower in Wyoming where they were threatened by a huge bear. In Norse mythology these were the goddess Freya’s hens. The name we know them by has rather misty origins. Some think the Greek name is from the mother of the seven sisters, Pleione. The Greek word for sail is similar to Pleiades, and it seems the appearance of the Pleiades in the morning sky saw the best sailing weather in the Mediterranean.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Devil's Tower

Seven maidens being attacked by a giant bear, having fled to the top of Devil’s Tower in Wyoming. Painting by Herbert Collins, https://www.nps.gov/deto.

The Pleiades, about what you'd see in binoculars.

The Pleiades, about what you’d see in binoculars, more than the 6 or 7 stars visible to the naked eye. The brighter stars are Freya’s Hens and also the Seven Sisters and Indian maidens. Credit Bob Moler.

Pleiades finder animation

Pleiades finder animation looking east about 8 pm in mid-November. Created using Stellarium.

11/16/2020 – Ephemeris – How to find the Pleiades or Seven Sisters

November 16, 2020 Comments off

This is Ephemeris for Monday, November 16th. Today the Sun will be up for 9 hours and 31 minutes, setting at 5:13, and it will rise tomorrow at 7:43. The Moon, 1 day past new, will set at 6:31 this evening.

A marvelous member of the autumn skies can be found low in the east after 8 in the evening. It is the famous star cluster called the Pleiades or the Seven Sisters. I might also add the ‘Tiny Dipper’. Many people can spot a tiny dipper shape in its six or seven stars, and mistake it for the Little Dipper. When I was nearsighted*, though corrected, I never had been able to see more than a few stars and a bit of fuzz. However, with binoculars, even I could see over a hundred stars appear along with the dipper shape of the brightest. The fuzz I saw was unresolved stars, but in photographs the Pleiades actually contain wisps of the gas and dust they are currently passing through. In Greek mythology the sisters were daughters of the god Atlas. I’ll be revisiting the Pleiades several times this autumn, winter, and as they disappear in the west in evening twilight next spring.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

*My vision was corrected with cataract surgery a few years ago. The Pleiades now have a granular appearance now.

Addendum

Pleiades finder animation

Pleiades finder animation looking east at 8 pm, November 16th. Click on the image to enlarge. Created using Stellarium.

Aldebaran

Aldebaran in the ‘V’ shape of the Hyades (The face of Taurus the bull) with the Pleiades above. Created using Stellarium.

Greek Pleiades

The Greek Pleiades a painting by Elihu Vedder in the Metropolitan Museum of Art, New York City. Public Domain.

07/10/2020 – Ephemeris – The constellation Cygnus the swan

July 10, 2020 Comments off

This is Bob Moler with Ephemeris for Friday, July 10th. Today the Sun will be up for 15 hours and 20 minutes, setting at 9:28, and it will rise tomorrow at 6:08. The Moon, 2 days before last quarter, will rise at 12:52 tomorrow morning.

Fairly high in the east at 11 p.m. Is the constellation of Cygnus the swan, flying south through the Milky Way. It is also called the Northern Cross. At the left, the tail of the swan or the head of the cross is the bright star Deneb, one of the stars of the Summer Triangle. The next star right is Sadr the intersection of the body and the wings of the swan seen in flight, or the intersection of the two pieces of the cross. There are two or three stars farther to the right that delineate the swan’s long neck or upright of the cross, that ends with the star Alberio in the beak of the swan or foot of the cross. The crosspiece of the cross extends to the stars on either side of the intersection star Sadr, while the swan’s wings extend to a couple more stars each.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Cygnus finder animation

Animated Cygnus finder chart. Included also are, beside Deneb, the other stars of the Summer Triangle: Vega and Altair and their constellations Lyra the harp and Aquila. See if you can find them. Click on the image to enlarge it. Created using Stellarium.

06/12/2020 – Ephemeris – The Summer Triangle proclaims that summer is almost here

June 12, 2020 1 comment

This is Bob Moler with Ephemeris for Friday, June 12th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:29, and it will rise tomorrow at 5:56. The Moon, 1 day before last quarter, will rise at 2:27 tomorrow morning.

Summer skies are coming. It’s only 8 days until summer officially arrives. It is a calendar day early this year because of the extra day added in February for the leap year. Looking to the eastern sky at 11 pm are three bright stars in a large triangle. The top star Vega is about half way up the sky to the zenith, and the brightest of the three. It’s in the small constellation of Lyra the harp. Lowest of the stars and just about due east is Altair in Aquila the eagle. Completing the triangle is Deneb in the northeast in the tail of Cygnus the swan or the head of the horizontal Northern Cross. These three stars make up the Summer Triangle. Be that as it may, the Summer Triangle will be in our evening sky moving slowly westward until December.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Finder animation for the Summer Triangle, seen in red for 11 pm, June 12th. Created using Stellarium and GIMP.

02/20/2020 – Ephemeris – The Winter Triangle

February 20, 2020 Comments off

Ephemeris for Thursday, February 20th. Today the Sun will be up for 10 hours and 41 minutes, setting at 6:17, and it will rise tomorrow at 7:34. The Moon, 3 days before new, will rise at 6:53 tomorrow morning.

I usually talk about the Winter Circle of bright stars, but some other astronomers talk about the Winter Triangle. The stars involved are Betelgeuse in the hunter Orion, Sirius in Canis Major, Orion’s large hunting dog, and Procyon in Canis Minor, his other small hunting dog. These three stars enclose a rather blank piece of sky with the faint Milky Way running through it and the equally invisible constellation of Monoceros the unicorn. The Summer Triangle has three bright stars with no other close competition. The Winter Triangle has 4 other bright stars near it. Any three of these would make a nice triangle. One of these stars, Betelgeuse has been the news recently because it is dimming to an unprecedented degree.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Winter Triangle

The Winter Triangle. It enclose a pretty blank space where Monoceros the unicorn lies. Created using Stellarium with my annotations for the Winter Triangle. By the way, Betelgeuse is currently only as bright as Bellatrix, the star next to the “n” in Orion.

10/24/2019 – Ephemeris – Let’s find Aquarius

October 24, 2019 Comments off

Ephemeris for Thursday, October 24th. Today the Sun will be up for 10 hours and 33 minutes, setting at 6:43, and it will rise tomorrow at 8:11. The Moon, half way from last quarter to new, will rise at 4:41 tomorrow morning.

One of the constellations of the zodiac is in the southeastern sky at 8 in the evening. It’s the constellation of Aquarius the water bearer. The image that is supposed to be depicted in the stars is that of a fellow spilling a stone jar of water. Aquarius is fairly hard to spot because it is made of faint stars. One part of him, though, is easy to spot. That is the Water Jar, an asterism or informal constellation. It is a distinctive small nearly equilateral triangle of stars with another star in the center. Stars extending to the right from the water jar are the yoke he’s holding the water jar with. The Water jar is just below the top of the head of the upside down Pegasus the flying horse. The water is flowing down a vertical line of stars.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Aquarius finder animation

Aquarius finder animation for tonight at 8 p.m. October 24, 2019. Created using Stellarium and GIMP.

08/20/2019 – Ephemeris – To find Sagittarius, look for the Teapot

August 20, 2019 Comments off

Ephemeris for Tuesday, August 20th. Today the Sun will be up for 13 hours and 49 minutes, setting at 8:40, and it will rise tomorrow at 6:51. The Moon, 3 days before last quarter, will rise at 11:16 this evening.

Due south and low in the sky at 10:30 p.m. now is one of my favorite asterisms the Teapot of the constellation Sagittarius. Sagittarius classically represents a centaur with a bow and arrow aimed at the heart of the constellation Scorpius to its west. I can find the bow and arrow here, but the half man half horse figure of the centaur eludes me. However the stout little teapot of the children’s song is quite obvious, with its base, lid on top, handle to the left and the spout to the right. To make things more realistic the bright Milky Way seems to rise like steam from its spout. As the night goes on the Teapot slides westward and appears to tilt, pouring its tea on the southwestern horizon. Saturn this year is above and left of it.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Sagittarius Teapot finder animation based of August 20, 2019 at 10:30 p.m. It includes the tiny asterism Terebellum, Latin for auger. It’s made to faint 4th and 5th magnitude stars. Created using Stellarium and GIMP.

07/26/2019 – Ephemeris – Scorpius the starry scorpion crawls over the southern horizon

July 26, 2019 Comments off

Ephemeris for Friday, July 26th. Today the Sun will be up for 14 hours and 53 minutes, setting at 9:15, and it will rise tomorrow at 6:23. The Moon, 2 days past last quarter, will rise at 2:11 tomorrow morning.

There’s a large constellation located low in the south at about about 11 tonight. It’s Scorpius the scorpion. Its brightest star is Antares in its heart, a red giant star, that I get calls about from time to time as being a UFO. With bright Jupiter above and left of it, it won’t be as noticeable. From Antares to the right is a star then a vertical arc of three stars that is its head. The Scorpion’s tail is a line of stars running down to the left of Antares swooping to the horizon before coming back up and ending in a pair of stars that portray his poisonous stinger. There is a beautiful star cluster seen in binoculars at that first bend in the tail that is unfortunately too low to appreciate from this far north. I was very impressed with it when spotting it from the Florida Keys when I was down there in 1986 observing Halley’s Comet.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Animated finder chart for Scorpius the scorpion for 11 p.m. July 26, 2019. A year from now Jupiter will be just pass where Saturn is, and Saturn will be just off the frame of this image. Also note the “Teapot” asterism of Sagittarius just left of the scorpion with the Milky Way as steam rising from its spout.