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Ephemeris: 07/28/2025 – Deneb, a truly brilliant star
This is Ephemeris for Monday, July 28th. Today the Sun will be up for 14 hours and 48 minutes, setting at 9:12, and it will rise tomorrow at 6:26. The Moon, halfway from new to first quarter, will set at 11:06 this evening.
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, is deceptive. 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 almost as bright as the quarter moon. It is possibly as bright as 200 thousand Suns; and a huge star, possibly as large as half the diameter of Earth’s orbit. For all this, it is only 19 to 25 times the mass of the Sun.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 07/15/2025 – Finding Cygnus the swan
This is Ephemeris for Tuesday, July 15th. Today the Sun will be up for 15 hours and 13 minutes, setting at 9:25, and it will rise tomorrow at 6:12. The Moon, 2 days before last quarter, will rise at 12:01 tomorrow morning.
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, an asterism or informal constellation. 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 in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 06/13/2025 – Finding the Summer Triangle
This is Ephemeris for Friday, June 13th. 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, 2 days past full, will rise at 11:59 this evening.
Summer skies are coming. It’s only 7 days until summer officially arrives. Looking to the eastern sky at 11 pm are three of the brightest stars in a large triangle. The top star Vega is about halfway 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, which isn’t an official constellation. It’s one of the many informal star patterns called asterisms. The Summer Triangle will be in our evening sky moving slowly westward until December.
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 11/04/2024 – The Milky Way in Autumn
This is Ephemeris for Monday, November 4th. Today the Sun will be up for 10 hours and 1 minute, setting at 5:26, and it will rise tomorrow at 7:26. The Moon, 4 days past new, will set at 6:58 this evening.
As of yesterday the sunsets and sunrises have slipped back an hour so we have darker evenings and brighter mornings, as we came back to Standard Time. It seems odd that we spend less time of the year under Standard Time than we do under Daylight Time. Anyway, looking at the evening sky we see that Venus tonight will be above the four-day-old crescent Moon in the southwest after sunset. By 7 PM the northernmost star of the Summer Triangle, Deneb in Cygnus the swan or the Northern Cross, will be almost directly overhead. And the Milky Way at that time will run from northeast, overhead to the southwestern horizon. Remember tomorrow is Election Day. Make sure you cast your ballot before the end of voting tomorrow, if you haven’t already.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.
Addendum
Ephemeris: 08/23/2024 – The dimmest star of the Summer Triangle is really the brightest
This is Ephemeris for Friday, August 23rd. Today the Sun will be up for 13 hours and 39 minutes, setting at 8:34, and it will rise tomorrow at 6:56. The Moon, 3 days before last quarter, will rise at 10:29 this evening.
This evening when it gets dark enough the bright star Deneb in Cygnus the swan will be very high in the east. Deneb is the dimmest star of the Summer Triangle. Of the other stars of the triangle, Vega is nearly overhead, while Altair is lower in the south-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 at least as bright 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 astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT–4 hours). Times will be different for other locations.
Addendum
Ephemeris: 08/02/2024 – The Northern Cross
This is Ephemeris for Friday, August 2nd. Today the Sun will be up for 14 hours and 35 minutes, setting at 9:06, and it will rise tomorrow at 6:31. The Moon, 2 days before new, will rise at 5:12 tomorrow morning.
The star Deneb is high in the east-northeast. It is the dimmest of the three stars of the Summer Triangle. It is at the head of the Northern Cross, an informal constellation or asterism. The upright extends to the South. The crossbeam can be seen crossing the star just south of Deneb. There’s also a constellation there. It’s actually Cygnus the swan flying southward along the Milky Way with its neck outstretched. The Anishinaabe natives peoples of our area see Ajijaak the crane, also with a long neck flying north, but also long legs trailing to the south, its wings outstretched. In Greek mythology Cygnus was the guise of the god Zeus when he seduced Leda, whose offspring was Pollux, one of the Gemini twins.
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
Ephemeris: 05/27/2024 The evening sky is transitioning into summer
This is Bob Moler with Ephemeris for Memorial Day, Monday, May 27th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:17, and it will rise tomorrow at 6:02. The Moon, 3 days before last quarter, will rise at 1:36 tomorrow morning.
The sky tonight at 10:30 is beginning to show the transition from spring to summer. Antares in Scorpius is very low in the southeast, rising and chasing away Orion who has disappeared in the West. According to Greek mythology, at least in one story, Orion was killed by the sting of a giant scorpion and so neither he nor Scorpius the scorpion can be in the sky at the same time. The bright star Spica in Virgo the virgin is due South at that time, with Leo the lion in the southwest. Very high in the southeast is the star Arcturus. The Big Dipper is overhead. And in the east-northeast high up this is the bright star Vega, one of the stars of the summer triangle. The second star of the triangle Deneb is lower in the northeast. The third star has yet to rise.
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
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.
Bob Moler's Ephemeris Blog 