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Ephemeris: 08/25/2025 – Two fascinating constellations in and near the Summer Triangle
This is Bob Moler with Ephemeris for Monday, August 25th. Today the Sun will be up for 13 hours and 33 minutes, setting at 8:31, and it will rise tomorrow at 6:58. The Moon, 2 days past new, will set at 9:27 this evening.
There are two small constellations in and near the Summer Triangle of bright stars. Both are near Altair the bottom star of the triangle in the southeast. The first is Delphinus the dolphin to the left of Altair. Delphinus is made-up of a small squished box of stars with another star below. It does look a dolphin leaping out of the water. The legendary Greek poet Arion, according to myth, was rescued by a dolphin. Also, the little squished box is an asterism called Job’s Coffin, though no one knows the origin of that name. The second constellation is above Altair, and within the Summer Triangle. It is called Sagitta the arrow. The stars do line up to look like a short arrow. It’s supposed to represent Cupid’s dart.
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: 09/12/2023 – Two small but distinctive constellations by the Summer Triangle
this is Ephemeris for Tuesday, September 12th. Today the Sun will be up for 12 hours and 41 minutes, setting at 7:59, and it will rise tomorrow at 7:19. The Moon, 2 days before new, will rise at 5:37 tomorrow morning.
There are two small constellations in and near the Summer Triangle of bright stars. Both are near Altair the bottom star of the triangle in the southeast. The first is Delphinus the dolphin to the left of Altair. Delphinus is made-up of a small squished box of stars with another star below. It does look a dolphin leaping out of the water. The legendary Greek poet Arion, according to myth, was rescued by a dolphin. Also the little squished box is an asterism called Job’s Coffin, though no one knows the origin of that name. The second constellation is above Altair, and within the Summer Triangle. It is called Sagitta the arrow. The stars do line up to look like a short arrow. It’s supposed to represent Cupid’s dart.
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
Painting circa 1938.
Ephemeris: 08/17/2023 – Finding Aquila the eagle
This is Bob Moler with Ephemeris for Thursday, August 17th. Today the Sun will be up for 13 hours and 58 minutes, setting at 8:45, and it will rise tomorrow at 6:48. The Moon, 1 day past new, will set at 9:40 this evening.
Aquila the eagle is a constellation that lies in the Milky Way. It’s in the southeastern sky as it gets dark. Its brightest star, Altair, is one of the stars of the Summer Triangle, the group of three bright stars high in the east to southeastern sky in the evening now. Altair, in the head of the eagle, is flanked by two slightly dimmer stars, the shoulders of the eagle. The eagle is flying northeastward through the Milky Way. Its wings are seen in the wing tip stars. A curved group of stars to the lower right of Altair is its tail. Within Aquila, the Milky Way shows many dark clouds as part of the Great Rift that splits it here. The other summer bird is Cygnus the swan above and left of Aquila, flying in the opposite direction. It was said this was the eagle that attended the Roman god Jupiter.
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. Two small constellations are found near the head of Aquila. Created using Stellarium. Near the beak of the image of Aquila is Sagitta the arrow. A bit further left of Altair are the distinctive six stars of Delphinus the dolphin, as if it is jumping out of the water. Created using Stellarium and GIMP.
Animated photograph of Aquila the eagle with constellation lines taken on August 13, 2018, during the Perseid meteor shower. Alas, there are no Perseids in this photograph. The reddening of the image was in part due to the smoke and haze if the western states wildfires that year. Taken by me and processed using Registax and GIMP.
08/19/2022 – Ephemeris – Finding the small constellations near the Summer Triangle
This is Ephemeris for Friday, August 19th. Today the Sun will be up for 13 hours and 52 minutes, setting at 8:41, and it will rise tomorrow at 6:51. The Moon, at last quarter today, will rise at 12:32 tomorrow morning.
I’ve already talked about the three constellations whose bright stars mark the Summer Triangle: Vega in Lyra the harp, Deneb in Cygnus the swan, and Altair in Aquila the eagle. There are two small constellations near the south end of the triangle near Altair. These are Delphinus the dolphin and Sagitta the arrow. Delphinus is easily spotted, as it’s five or six stars appear as a tiny dolphin leaping out of the water. Sagitta appears as a very short arrow. An interesting sight can be spotted in binoculars near the tail end of Sagitta. It’s 7 stars in a nearly straight line, with a hook of four stars below the center of the line. It’s called The Coathanger. It’s even better if seen in a finder telescope, which inverts the image.
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
Finding the small constellations of Delphinus the dolphin and Sagitta the arrow among the stars and constellations of the Summer Triangle. Created using Stellarium and GIMP.
How to locate the binocular asterism of the Coathanger. It is also known as Collinder 399, Brocchi’s Cluster and Al Sufi’s Cluster. It’s not a real star cluster, but a random arrangement of stars at various distances, that from the solar system make a distinctive pattern.
09/15/2020 – Ephemeris – The dolphin and the arrow, small summer constellations
This is Bob Moler with Ephemeris for Tuesday, September 15th. Today the Sun will be up for 12 hours and 30 minutes, setting at 7:52, and it will rise tomorrow at 7:23. The Moon, 2 days before new, will rise at 6:01 tomorrow morning.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is nearly overhead in our sky at 10 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Delphinus and Sagitta finder animation. Created using Stellarium and GIMP.
08/23/2019 – Ephemeris – Two small constellations around the Summer Triangle
Ephemeris for Friday, August 23rd. Today the Sun will be up for 13 hours and 41 minutes, setting at 8:35, and it will rise tomorrow at 6:55. The Moon, at last quarter today, will rise at 12:43 tomorrow morning.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is overhead in our sky at 10 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart. Above-right of Sagitta binoculars will find a little star group called the Coat hanger.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Delphinus and Sagitta finder animation. Created using Stellarium and GIMP.
Closeup of Sagitta and the binocular asterism the Coathanger. Created using Stellarium.
09/06/2018 – Ephemeris – The constellations of Delphinus and Sagitta
Ephemeris for Thursday, September 6th. The Sun will rise at 7:11. It’ll be up for 12 hours and 59 minutes, setting at 8:10. The Moon, 3 days before new, will rise at 4:19 tomorrow morning.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is nearly overhead in our sky at 10 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Delphinus and Sagitta finder animation. Click on image to enlarge. Created using Stellarium and GIMP.
09/11/2017 – Ephemeris – The celestial dolphin and an arrow
Ephemeris for Monday, September 11th. The Sun will rise at 7:16. It’ll be up for 12 hours and 43 minutes, setting at 8:00. The Moon, 2 days before last quarter, will rise at 11:27 this evening.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is high in the east to overhead in our sky at 9 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do, and told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Delphinus and Sagitta finder animation. Created using Stellarium and GIMP. Click on image to enlarge.
10/04/2016 – Ephemeris – Celestial dolphin and Cupid’s arrow
Ephemeris for Tuesday, October 4th. The Sun will rise at 7:45. It’ll be up for 11 hours and 31 minutes, setting at 7:16. The Moon, 4 days past new, will set at 9:28 this evening.
There’s two small constellations I’ve overlooked in the heat of Summer. Located above the southernmost star of the Summer Triangle of three of the brightest stars in the sky, which is nearly overhead at 9 p.m., is the tiny constellation of Delphinus the dolphin, which is seen high in the south. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks appreciated this aquatic mammal as we do. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow, which represents Cupid’s dart.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Delphinus and Sagitta seen in an animation showing them without captions, with stick constellations, labeled, and as an artist sees them. Created using Stellarium.
09/07/2015 – Ephemeris – Small summer constellations
Ephemeris for Labor Day*, Monday, September 7th. The Sun will rise at 7:11. It’ll be up for 12 hours and 56 minutes, setting at 8:08. The Moon, 2 days past last quarter, will rise at 2:47 tomorrow morning.
Located below the eastern edge of the Summer Triangle of three of the brightest stars in the sky, which is overhead in our sky at 10 p.m., is the tiny constellation of Delphinus the dolphin. Delphinus’ 6 stars in a small parallelogram with a tail, really does look like a dolphin leaping out of the water. The parallelogram itself has the name Job’s Coffin. The origin of this asterism or informal constellation is unknown. Of the dolphin itself: the ancient Greeks told stories of dolphins rescuing shipwrecked sailors. There’s another tiny constellation to the right of Delphinus, Sagitta the arrow a small thin group of 5 stars, which represents Cupid’s dart. Behind Sagitta binoculars will find a little star group called the Coat hanger.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle. Created using Stellarium and The Gimp.
Delphinus, Sagitta and the Coat hanger. Diagram created using Stellarium.
* In the US Labor Day is celebrated on the first Monday in September and is considered the unofficial end of summer. The weather generally agrees. Last week we had a preview of fall weather. This week, except for today has been hot. The outlook for next week is looking decidedly cooler. Most schools in Michigan start the day after Labor Day. and end after June 1st. The unofficial start of summer is Memorial day, the last Monday in May.
Bob Moler's Ephemeris Blog 