01/09/2023 – Ephemeris – The Summer Triangle is still with us in the early evening

This is Ephemeris for Monday, January 9th. Today the Sun will be up for 9 hours and 1 minute, setting at 5:21, and it will rise tomorrow at 8:18. The Moon, 3 days past full, will rise at 7:56 this evening.

The bright Moon is now slowly leaving the evening sky tonight, giving us nearly an hour of dark skies after 7 pm. At 7pm, Orion is holding forth in the east-southeast. At that time, also, the Summer Triangle is still in the sky, west and northwest. The Northern Cross, which is also the constellation of Cygnus the swan, is standing upright in the west northwestern sky. Its top star Deneb, dimmest of the three Summer Triangle stars, will not set for observers north of Traverse City, though it will take a flat northern horizon and exceptionally clear skies to spot it at its lowest in the north. Altair, the southernmost of the triangle stars will set first in the west at 7:57 pm, Vega, the brightest will set in the northwest at 9:41 pm.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT –5 hours). They may be different for your location.

Addendum

The setting Summer Triangle and Northern Cross in the west and northwestern sky at 7 pm tonight, January 9th.

07/29/2022 – Ephemeris – The celestial Sand Hill Crane

This is Ephemeris for Friday, July 29th. Today the Sun will be up for 14 hours and 46 minutes, setting at 9:12, and it will rise tomorrow at 6:26. The Moon, 1 day past new, will set at 10:14 this evening.

Let’s look again at the constellation called Cygnus the swan and the informal constellation or asterism made from most of its stars, the Northern Cross. Cygnus is the official International Astronomical Union constellation name. However, the indigenous Anishinaabe people of our area had another bird in mind when seeing these stars, which are now fairly high in the east in the evening: Ajijaak, (pronounced a-ji-jock) a Sand Hill crane. While the swan is flying, neck outstretched to the south through the Milky Way, the crane is flying northward with its long legs trailing behind. The bright star Deneb is at his head. Where I live, I see and hear the cranes with their creaking-door-like calls, and see a pair from time to time in a field south of where I live.

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 IAU Cygnus the swan and the Anishinaabe Ajijaak the Sand Hill crane constellations demonstrated via an animated GIF image. Credit Stellarium (both star lore images are embedded in Stellarium). The Anishinaabe image is from Ojibwe Giizhig Anung Masinaaigan – Ojibiwe Sky Star Map created by A. Lee, W. Wilson, and C. Gawboy.

07/15/2022 – Ephemeris – How to find the constellation of Cygnus the swan

This is Ephemeris for Friday, July 15th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:25, and it will rise tomorrow at 6:12. The Moon, 2 days past full, will rise at 11:23 this evening.

Located 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 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

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. Created using Stellarium.

07/14/2022 – Ephemeris – The dimmest Summer Triangle star is actually the brightest

This is Ephemeris for Thursday, July 14th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:26, and it will rise tomorrow at 6:11. The Moon, 1 day past full, will rise at 10:49 this evening.

This evening, when it gets dark enough, the bright star Deneb in Cygnus the swan will be high in the east-northeast. I’ll cover Cygnus tomorrow when the sky is darker. Deneb is the dimmest star of the summer triangle. Of the other stars of the triangle, Vega is higher in the east, while Altair is lower in the southeast. Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars. That’s because of its vast distance of maybe 1,550 light years, 57 times the distance of Vega. If brought as close as Vega, Deneb would be as bright, at least, as the first quarter moon. It is possibly as bright as 196 thousand Suns; and it’s a huge star, possibly as large in diameter as the orbit of the Earth. For all this, it is only 23 or so times the mass 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

The Summer Triangle. Created using Stellarium and The Gimp.

If you put Deneb in the search box, you will find that the content of the posts, over the years, about the star are nearly identical. However, the distance estimates vary widely. It is too far away for trigonometric parallax measurements by earth based telescopes. Though in the range of ESA’s Hipparcos and Gaia satellites, it is too bright. So other less accurate measurements are used. I don’t think it involves coin flipping. The assumed distance also affects estimates of luminosity, and mass.

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

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

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.

10/05/2021 – Ephemeris – Can you spot the North American Nebula?

This is Bob Moler with Ephemeris for Tuesday, October 5th. Today the Sun will be up for 11 hours and 29 minutes, setting at 7:15, and it will rise tomorrow at 7:47. The Moon, 1 day before new, will rise at 7:46 tomorrow morning.

Most of what we see in the Milky Way are just masses of stars, but there are bright clouds of gas, or to name them properly: emission nebulae. These bright clouds are areas of star formation. It is the ultraviolet light from young massive stars that light up the clouds they were formed from. A bright one, easily visible in binoculars, is just about overhead at 9 p.m. Called the North American Nebula, a glow, that in photographs is shaped much like our continent, is just east of the star Deneb which is practically overhead in the evening. Deneb is the northernmost star of the Summer Triangle, and brightest star in Cygnus the swan or Northern Cross. There are many other nebulae in the Milky Way, visible in binoculars and small telescopes. Many enjoyable hours can be spent sweeping the Milky Way for nebulae and star clusters.

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

North American Nebula finder animation. I’ve dimmed down the stars a bit and increased the brightness of the Milky Way to aid in spotting the nebula. It requires dark skies to see it. I believe I can make it out with the naked eye too. Click on the image to enlarge it. Created using Stellarium and GIMP.

One of my old photographs of Deneb and the North American Nebula, digitized from a slide.

Better view of the North American Nebula taken by Scott Anttila.

07/08/2021 – Ephemeris – How to find the constellation of Cygnus the swan

This is Ephemeris for Thursday, July 8th. Today the Sun will be up for 15 hours and 23 minutes, setting at 9:29, and it will rise tomorrow at 6:06. The Moon, 1 day before new, will rise at 5:23 tomorrow morning.

Halfway up the sky in the east at 11 pm 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 to the 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, a beautiful double star in telescopes, 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 for a couple more stars each side.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT-4). They may be different for your location.

Addendum

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.

06/29/2021 – Ephemeris – The Summer Triangle

This is Ephemeris for Tuesday, June 29th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon, 2 days before last quarter, will rise at 1:14 tomorrow morning.

Dominating the eastern sky at 11 pm are three bright stars. These are all first magnitude stars, members of the group of 21 brightest stars in the night sky. Highest, in the east, is Vega, the brightest of the three. It and a small, slim parallelogram of stars below it belong to the constellation of Lyra the harp. Below it to the northeast is Deneb, dimmest of the three at the head of the horizontally appearing Northern Cross, an informal constellation or asterism. Properly, Deneb is in the tail of Cygnus the swan flying south through the Milky Way. The third star of the three is Altair, lower still, but in the east-southeast at the head of Aquila the Eagle. These three stars are in a large asterism called the Summer Triangle, which will be with us through summer and fall.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT-4). They may be different for your location.

Addendum

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

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

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

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.

07/02/2020 – Ephemeris – The star Deneb in Cygnus the swan

This is Ephemeris for Thursday, July 2nd. Today the Sun will be up for 15 hours and 29 minutes, setting at 9:31, and it will rise tomorrow at 6:02. The Moon, 3 days before full, will set at 4:29 tomorrow morning.

This evening when it gets dark enough the bright star Deneb in Cygnus the swan will be high in the east-northeast. Deneb is the dimmest star of the summer triangle. Of the other stars of the triangle, Vega is higher in the east, while Altair is lower in the southeast. Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars. Its vast distance of possibly 2,600 light years is over 100 times the distance of Vega. If brought as close as Vega, Deneb would be as bright at least as the quarter moon. It is possibly as bright as 200 thousand Suns; and a huge star, possibly as large in diameter as the orbit of the Earth. For all this it is only 19 or so times the mass of the Sun.

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

Addendum

Deneb with the other stars and constellations in the Summer Triangle. Created using Stellarium.

One of my old photographs of Deneb and the North American Nebula digitized from a slide.