Archive
Ephemeris: 06/17/2025 – Finding the naked-eye double star Mizar and Alcor
This is Ephemeris for Tuesday, June 17th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:56. The Moon, 1 day before last quarter, will rise at 1:36 tomorrow morning.
In tonight’s sky, the Big Dipper is high in the northwest hanging from its handle. In its handle is a star or two that are fascinating. It’s the star at the bend in the handle. It’s called Mizar. Next to it, for those with good eyesight, is a dimmer star, called Alcor. The name Mizar is from the Arabic, meaning apron or cover, while Alcor means the forgotten one. In ancient times the ability to actually see both stars was a test for good eyesight, especially for Arabic warriors. The pair is also known as the “Horse and the Rider”. Some Native American tribes saw the handle stars as hunters tracking the Great Bear, Ursa Major, of which the Big Dipper is a part, rather than its very unnatural tail. Dim Alcor became a hunting dog.
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: 06/16/2025 – Mars meets Regulus tonight
This is Ephemeris for Monday, June 16th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:30, and it will rise tomorrow at 5:56. The Moon, 2 days before last quarter, will rise at 1:17 tomorrow morning.
If one looks out tonight to the west after dark, two bright stars will appear very close together. One appears to the upper right of the other and very close, about one and a half moon-widths apart. The star to the upper right will have a reddish hue. It’s not a star at all but the planet Mars. The other one is a star, Regulus in Leo the lion. After tonight Mars will continue its trek eastward against the stars heading towards another bright star, Spica in Virgo. It will pass north of that star on September 11th. Mars will pass any particular star near the ecliptic on the average of one year, ten and a half months, which is its orbital period of the Sun. Since we’re viewing it from the moving Earth, along with Mars’ eccentric orbit, the interval can vary greatly.
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: 06/12/2025 – Another look at the star Spica
This is Ephemeris for Thursday, 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 past full, will rise at 11:20 this evening.
In the south-southwest at 11 PM is the bright star Spica in Virgo the virgin. Arcturus, high in the south, is much brighter than Spica and has an orange tint to Spica’s bluish hue. In fact, Spica is the 15th brightest and the bluest of the 21 first magnitude stars. That means that it has a really hot surface temperature. Spica is actually two stars in a tight 4-day orbit of each other. They are both reasonably matched in mass and brightness. I found that out once photographing a lunar eclipse near Spica, The star came out very blue. The twin stars of Spica are 250 light years away. I’m glad the stars are young now. They will have a very interesting future as they age and interact in the next few million years.
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: 06/11/2025 – Checking on the naked-eye planets for this week
This is Ephemeris for Wednesday, June 11th. Today the Sun will be up for 15 hours and 31 minutes, setting at 9:28, and it will rise tomorrow at 5:56. The Moon, at full today, will rise at 10:31 this evening.
Let’s take our weekly look at the whereabouts of the naked-eye planets. Only one naked eye planet will be visible in the evening sky. That is reddish Mars, now approaching the bright star Regulus in the constellation Leo the lion, which it will pass just north of next Monday evening, June 16th. Both are seen in the western sky. They are currently about the same brightness, but Mars has an orange-reddish hue, while Regulus, to the left, is white. By 5 AM Venus will be seen very low in the east, as the Morning Star, with Saturn to the right and above it in the east-southeast. Venus will be visible until close to 5:40. For those with telescopes, Saturn’s rings are now slowly opening up again, and will for the next 7 years.
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
Venus and Saturn at 5 AM tomorrow morning, June 12th, 2025, low in the east. Created using Stellarium.
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on June 11, 2025. The night ends on the left with sunrise on the 12th. Click or tap on the image to enlarge it. Created using my LookingUp app and GIMP.
Ephemeris: 06/10/2025 – Tonight’s Strawberry Moon
This is Ephemeris for Tuesday, June 10th. Today the Sun will be up for 15 hours and 30 minutes, setting at 9:27, and it will rise tomorrow at 5:56. The Moon, 1 day before full, will set at 5:36 tomorrow morning.
The actual instant that the Moon will be full, that is opposite the Sun in the sky, will be 3:44 tomorrow morning. So tonight’s full moon will be fuller than tomorrow night’s Moon. This month’s full moon is also called the Strawberry Moon by Native Americans, because this is the month that strawberries ripen. Also, the term honeymoon comes from the fact that many weddings are in June, when the full moon is low in the sky in the south and has a yellowish or honey color due to haze and atmospheric preferential scattering of blue light. The darker areas of the Moon give the effect of a face called the Man in the Moon. There is also a rabbit in the Moon, curled around the upper edge, with head and ears to the right and body to the left.
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: 06/04/2025 – Taking our weekly look at where the naked-eye planets have wondered off to
This is Ephemeris for Wednesday, June 4th. Today the Sun will be up for 15 hours and 25 minutes, setting at 9:23, and it will rise tomorrow at 5:58. The Moon, 2 days past first quarter, will set at 2:57 tomorrow morning.
Let’s take our weekly look at the whereabouts of the naked-eye planets. At 10 PM this evening two naked eye planets will be out. Jupiter, is then very low on the west-northwestern horizon, difficult or impossible to find. Fading Mars, with its distinctive reddish hue, is in the west-southwest, at that time, though better seen when the skies are darker. It’s slowly approaching the bright star Regulus in Leo the lion, which it will pass on June 16th. By 5 AM Venus will be seen very low in the east, as the Morning Star, with Saturn to the right in the east-southeast and above it. Venus will be visible until close to 5:40. For those with telescopes, Saturn’s rings are now slowly opening up again, and will for the next 7 years.
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: 06/03/2025 – Looking at the Moon tonight
This is Bob Moler with Ephemeris for Tuesday, June 3rd. Today the Sun will be up for 15 hours and 23 minutes, setting at 9:23, and it will rise tomorrow at 5:58. The Moon, 1 day past first quarter, will set at 2:41 tomorrow morning.
For me, the best time to view the Moon with binoculars or a telescope is around first quarter and tonight’s Moon is just a day past first quarter. At this time we see the maximum amount of shadowing of the craters because the sunrise line which we call the terminator is cutting across, pretty much, the center of the Moon. Since the Moon is a pretty uniformly dark gray with light gray areas, shadows make all the difference in seeing detail. One thing to notice on tonight’s Moon is that the southern or bottom part of the Moon has a lot of craters and is bright gray. This is called the lunar highlands and is brighter than the darker areas to the north and on the western side of the Moon, which are covered by the maria or seas, plains of solidified lava flows.
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
Translations of some lunar feature names according to Virtual Moon Atlas
Lacus Mortis – Lake of Death
Lacus Somniorum – Lake of Dreams
Mare Crisium – Sea of Crises
Mare Fecunditatis – Sea of Fruitfulness
Mare Frigoris – Sea of Cold
Mare Imbrium – Sea of Showers
Mare Nectaris – Sea of Nectar
Mare Serenitatis – Sea of Serenity
Mare Tranquillitatis – Sea of Tranquility
Mare Vaporum – Sea of Vapors
Montes Alpes – Alps Mountains
Montes Apenninus – Apennines Mountains
Sinus Asperitatis – Bay of Roughness
Sinus Medii – Central Bay
Note: Mare is pronounced Mar-e, and Maria is pronounced Mar-e-a.
These features, for the most part, were named by Giovanni Battista Riccioli in 1651, when he produced the first accurate map of the Moon. Craters are named for persons, real or otherwise. Features like Seas, Lakes and Bays were given fanciful names. Labels are centered on their feature where possible.
Ephemeris: 05/29/2025 – Finding the celestial dragon
This is Ephemeris for Thursday, May 29th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:01. The Moon, 3 days past new, will set at 12:40 tomorrow morning.
High in the northern sky at 11 p.m. lies the twisted constellation of Draco the dragon. This dragon is more like the snakelike dragon of the Chinese New Year parades than the dinosaur-like dragon of European legend. I find it better to start at the tail of Draco, to trace him out in the stars. Draco’s tail ends between the Big and Little Dippers high in the north-northwest. The Dragon is seen in a line of stars that extends parallel to the handle of the Big Dipper before curving around the bowl of the Little Dipper then bends back down to the level of Polaris in the north-northeast before turning toward the east. The head of Draco is an odd box of stars near the bright star Vega, in the east. Though not made up of very bright stars, Draco has an easy shape to trace.
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: 05/28/2025 – Our weekly look at the whereabouts of the naked-eye planets
This is Ephemeris for Wednesday, May 28th. Today the Sun will be up for 15 hours and 15 minutes, setting at 9:18, and it will rise tomorrow at 6:01. The Moon, 2 days past new, will set at 11:50 this evening.
Let’s take our weekly look at the whereabouts of the naked-eye planets. At 10 PM this evening two naked eye planets will be out. Jupiter, is now low in the west-northwestern sky Underneath the waxing crescent Moon. The fading Mars, with its distinctive reddish hue, is in the west-southwest, at that time. It’s slowly approaching the bright star Regulus in Leo the lion, which it will pass on June 16th. By 5 AM Venus will be seen very low in the east, as the Morning Star, with Saturn to the right and a bit above it. Venus will require a low eastern horizon then. But it will rise and be visible until close to 5:45. For those with telescopes, Saturn’s rings are now opening up again, and will for the next 7 years.
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
Bob Moler's Ephemeris Blog 