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Archive for the ‘Asterism’ Category

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.

03/28/2019 – Ephemeris – The Big Dipper as seen by some other countries

March 28, 2019 Comments off

Ephemeris for Thursday, March 28th. Today the Sun will be up for 12 hours and 33 minutes, setting at 8:05, and it will rise tomorrow at 7:29. The Moon, at last quarter today, will rise at 4:21 tomorrow morning.

The Big Dipper is climbing up the northeastern sky at 9:30 in the evening, it’s seven stars shining brightly. The Big Dipper is not an actual constellation, recognized internationally. It’s part, the hind part, of Ursa Major, the great bear. The Big Dipper is an asterism or informal constellation. It is a distinctly North American constellation. For fugitive slaves, fleeing the southern states in the days before the Civil War, the Drinking Gourd, as they called it, showed the direction north to freedom. In England the dipper stars become the Plough, or Charles’ Wain (Charlemagne’s Wagon). In France, known for culinary delights it was the saucepan, or the cleaver. Many cultures saw what was familiar to them in these seven bright stars.

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

Addendum

Big Dipper as seen by different cultures

Cultural views of the Big Dipper as an Animation: Big Dipper/Sauce Pan, Plough (plow), Charle’s Wain (Charlemagne’s wagon), Cleaver.

12/04/2018 – Ephemeris – Auriga the Charioteer

December 4, 2018 Comments off

Ephemeris for Tuesday, December 4th. The Sun will rise at 8:03. It’ll be up for 8 hours and 59 minutes, setting at 5:02. The Moon, 3 days before new, will rise at 6:03 tomorrow morning.

The constellation Auriga the charioteer is half way up the sky in the east northeast at 9 p.m. It is a pentagon of stars, with the brilliant star Capella at the upper left of its corners. Capella represents a mama goat he’s carrying. A narrow triangle of stars just right of Capella are her kids, that is her baby goats. The Kids is an informal constellation or asterism. The Milky Way runs through Auriga, but it’s not very bright here. We are looking away from the center of the Milky Way to the more sparse outer parts. Within and near that pentagon, one can sweep with binoculars and low power telescopes to 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.

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

Addendum

Auriga

Auriga and neighboring constellations for 9 p.m. in early December. Created using Stellarium and GIMP.

11/13/2018 – Ephemeris – The Summer Triangle in autumn

November 13, 2018 Comments off

Ephemeris for Tuesday, November 13th. The Sun will rise at 7:37. It’ll be up for 9 hours and 39 minutes, setting at 5:16. The Moon, 2 days before first quarter, will set at 10:20 this evening.

The Summer Triangle is still in the sky at 9 p.m., even though it’s November. These three bright stars that straddle the Milky Way are high in the east for most of the summer, move overhead and begin to slide to the west in autumn. We will lose Altair, the southernmost of the three stars at 9 p.m. on the winter solstice, December 21st. We’ll lose the brightest, Vega in January. For the northern half of the IPR listening area the northernmost of the triangle stars, Deneb won’t quite set below a north Lake Michigan horizon. Next spring we’ll be waiting and watching for these three stars to rise, reclaim the skies, and bring again the warm summer skies. The winter skies do however have more bright stars than the summer sky.

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

Addendum

Summer Triangle tonight
The Summer Triangle of the three bright stars Vega, Deneb and Altair is still high in the west at 8 p.m. tonight. The zenith is near the top of the image. Created using Stellarium
Summer Triangle about to set.
The Summer Triangle with Altair about to set on the winter solstice at 9 p.,. Created using Stellarium.