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Ephemeris: 02/19/2026 – The star called Pup
This is Ephemeris for Thursday, February 19th. Today the Sun will be up for 10 hours and 40 minutes, setting at 6:17, and it will rise tomorrow at 7:35. The Moon, 2 days past new, will set at 9:05 this evening.
Sirius is the brightest nighttime star and is located in the south at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius last Monday, but there is another star in the Sirius system that is practically invisible due to Sirius’ dazzling glare. Its name is Sirius B, nicknamed the Pup, alluding to Sirius’ Dog Star title as the heart of Canis Major, Orion’s larger hunting dog. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path in the sky against the more distant stars. Sirius and the Pup have 50-year orbits of each other. The Pup was first seen in 1862. The Pup was the first of a new class of stars to be discovered, white dwarfs. The Pup, with the mass of the Sun, is packed into the volume of the Earth.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
by Howard E. Bond et al 2017 ApJ 840 70.
Ephemeris: 02/16/2026 – The Dog Star
This is Bob Moler with Ephemeris for President’s Day, Monday, February 16th. Today the Sun will be up for 10 hours and 31 minutes, setting at 6:12, and it will rise tomorrow at 7:39. The Moon, 1 day before new, will rise at 7:51 tomorrow morning.
The second-brightest star-like object in the evening sky is Sirius, also known as the Dog Star. It also is the brightest nighttime star in our skies period. Tonight at 9 p.m. it’s located in the southern sky. The Dog Star name comes from its position at the heart of the constellation Canis Major, the great dog of Orion the hunter. The three stars of Orion’s belt tilt to the lower left to Sirius. Sirius means ‘Dazzling One’, because of its great brilliance and twinkling. Its Egyptian name was Sopdet, and its first appearance in the dawn skies around July 20th signaled the flooding of the Nile, and the beginning of the agricultural year. The relationship of the heliacal rising of Sirius and the seasonal or tropical year lasted from about 2900 BCE to the start of the Common Era. Sirius owes much of its brilliance to the fact that it lies close to us, only 8.6 light years away.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Trivia Note
The Greeks invented the term “Dog days of summer” for the hottest days of July because they thought that Sirius added its intensity to the heat of the Sun to make it hotter out. So why doesn’t Sirius help warm our winter nights? Just asking.
Ephemeris: 02/09/2026 – Orion’s amazing belt stars
This is Ephemeris for Monday, February 9th. Today the Sun will be up for 10 hours and 11 minutes, setting at 6:02, and it will rise tomorrow at 7:50. The Moon, at last quarter today, will rise at 3:01 tomorrow morning.
Orion’s belt of three stars is one of the most noticeable star groupings in the sky. There are no other groups of three bright stars in a straight line visible anywhere else in the sky. The star’s names from left to right are Alnitak, Alnilam and Mintaka. They are actually a bit farther away than the other bright stars of Orion. Alnilam, the center star, is over three times the distance of red giant Betelgeuse above them and over twice as far as blue white giant star Rigel below them. Alnilam is 375 thousand times brighter than the Sun. These three stars were also known as Frigga’s Spindle by the Norsemen. Frigga, also known as Freya, is the goddess from which we get the name of the day of the week we call Friday.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 01/16/2026 – Comparing Orion’s two brightest stars
This is Ephemeris for Friday, January 16th. Today the Sun will be up for 9 hours and 13 minutes, setting at 5:29, and it will rise tomorrow at 8:15. The Moon, 2 days before new, will rise at 7:54 tomorrow morning.
Orion’s two brightest stars are kind of the same but different. Let me explain. Betelgeuse is a red giant star, extremely massive, maybe 14 to 19 times the sun’s mass. It is somewhere between 8 and 14 million years old, which compared to the sun is just a baby, except it is so massive that it is in the last million or so years of its life. Rigel is a bluish white and a bit more massive, about 21 times the mass of the sun, and maybe 8 million years old. It has used most of the hydrogen in its core, and is beginning to transition into its final years which is a few more millions of years. So it’s not as far along in its evolution as Betelgeuse and has not bloated out and turned red. Betelgeuse is 500 light years away, while Rigel is almost 900.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
Addendum
Ephemeris: 12/15/2025 – Capella, the winter star that never quite leaves us*
This is Ephemeris for Monday, December 15th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:02, and it will rise tomorrow at 8:14. The Moon, halfway from last quarter to new, will rise at 5:13 tomorrow morning.
Capella is the northernmost first magnitude stars. Tonight it shines in the northeastern sky. First magnitude stars are the 21 brightest stars in the night sky. Capella is the 6th brightest. Although I’ve always known it as the little she-goat, Capella’s name literally translates to “little goat.” Her three Kids are represented by a narrow triangle of stars positioned to the right of her in tonight’s evening sky. Capella is in the topmost corner of the pentagonal constellation of Auriga the Charioteer. Capella is actually a system of four stars only 43 light years away. And never sets for listeners in the Interlochen Public Radio transmission area who have a low northern horizon.
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; EST, UT – 5 hours) unless stated otherwise. Times will be different for other locations.
* If you live north of 44° north latitude.
Addendum
Ephemeris: 12/09/2025 – Aldebaran, the “Follower”
This is Ephemeris for Tuesday, December 9th. Today the Sun will be up for 8 hours and 53 minutes, setting at 5:02, and it will rise tomorrow at 8:09. The Moon, 2 days before last quarter, will rise at 10:34 this evening.
Tonight will be the night of the earliest sunset of the year. For the last few nights the Sun has been setting within the same minute. Soon the Sun will set noticeably later.
The bright star Aldebaran appears at the lower left tip of a letter V group of stars laying on it’s side, the Hyades star cluster and the face of Taurus the Bull. It’s in the east in the evening, above Orion. Aldebaran isn’t actually part of the group. The cluster is about 153 light years away, while Aldebaran is 65. The star has an orange hue because its surface is cooler than the Sun’s. However, Aldebaran is 44 times larger in diameter, and shines 425 times brighter than the Sun. The name Aldebaran means “Follower” because it follows the Pleiades star cluster across the sky.
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: 11/10/2025 – Waiting on a stellar explosion
This is Ephemeris for Monday, November 10th. Today the Sun will be up for 9 hours and 46 minutes, setting at 5:19, and it will rise tomorrow at 7:34. The Moon, 2 days before last quarter, will rise at 10:22 this evening.
According to one astronomer, that I mentioned last Thursday, today is about the day he expects a star to erupt as a nova in the constellation Corona Borealis, the Northern Crown. In the early evening, it will appear low in the west northwest. The star is designated T Coronae Borealis (T CrB). Its appearance should make the normal news outlets, because it will be the brightest stellar outburst in a very long time. It will appear just left of the constellation Corona Borealis and be about as bright as its brightest normal star. However, it will soon fade and to be less the naked eye brightness in about a week. So we’re hoping for clear skies, if it happens. If it’s not this time, the next predicted time is June 25th, next year. Or he could be wrong, and it could go off at any time. Spaceweather.com has more information.
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
According to a paper in the Research Notes of the American Astronomical Society, Jean Schneider with the Paris Observatory predicted that the next eruption of T Coronae Borealis would be somewhere around November 10th 2025, or June 25th 2026. The first prediction of the 27th of March earlier this year turned out to not have occurred. These were tentative predictions based on the orbit around each other, of the two stars involved. The period of 80 years between eruptions is an approximation. There is an additional periodicity due to the fact that the two stars involved, a red giant and a white dwarf, have an orbital period of about 228 days which is why the predictions are 228 days apart. There have been four previous eruptions of the star observed. The first was in 1217, the next in 1787, then in 1866 and then finally in 1946. The reason for the big gap between 1217 and 1787 is unknown. Either the star didn’t erupt, or more likely, nobody observed and recorded it. The times of the first two eruptions weren’t accurately reports, but fell within what the 228-day periodicity would explain.
T Coronae Borealis is far enough north in the sky so that it is visible sometime during the night, year round. Currently, it would be best seen at the end of twilight in the west northwest. This will shift over to the morning sky, before morning twilight, after about the 25th of November, only 15 days from now in the east northeast. This star like any other star that rises and sets does so approximately 4 minutes earlier each night, or 28 minutes per week. So after the 25th the best observing opportunity will be before dawn in the morning until much later in the late winter, when it will be available also in the evening sky again.
Ephemeris: 10/30/2025 – Algol, the perfect Halloween star
This is Ephemeris for Thursday, October 30th. Today the Sun will be up for 10 hours and 15 minutes, setting at 6:33, and it will rise tomorrow at 8:19. The Moon, 1 day past first quarter, will set at 2:03 tomorrow morning.
Not all the ghosts and goblins out tomorrow night will be children. One will be out every night because it’s a star. Its name is Algol, from the Arabic for Ghoul Star or Demon Star. It’s normally the second-brightest star in the constellation Perseus the hero, visible in the northeast this evening. The star is located where artists have drawn the severed head of Medusa, whom he had slain. Medusa was so ugly that she turned all who gazed upon her to stone. Algol is her still glittering eye. The star got these names before we knew what was wrong with it. It does a slow wink every two days, 21 hours. That’s because Algol is two stars that eclipse each other. Her next evening wink will be its dimmest at 10:12 p.m. Tuesday, November 4th.
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: 10/17/2025 – Fomalhaut, lonely again
This is Ephemeris for Friday, October 17th. Today the Sun will be up for 10 hours and 52 minutes, setting at 6:54, and it will rise tomorrow at 8:02. The Moon, halfway from last quarter to new, will rise at 5:04 tomorrow morning.
There’s a bright star that appears for only seven and a half hours on autumn evenings. Its appearance, low in the south in the evening, is a clear indication of autumn. It is currently below and right of the much brighter Saturn. The star’s name is Fomalhaut, which means fish’s mouth. That’s fitting because it’s in the constellation of Piscis Austrinus, the southern fish. At our latitude it’s kind of the fish that got away, because Fomalhaut is low in our skies where stars lose more than half their brightness. For the last few years Jupiter, then Saturn have kept it company. However, Saturn is moving on, having shifted into Pisces, leaving Fomalhaut to its lonely vigil in the south.
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: 08/04/2025 – Mars’ twin
This is Bob Moler with Ephemeris for Monday, August 4th. Today the Sun will be up for 14 hours and 31 minutes, setting at 9:04, and it will rise tomorrow at 6:33. The Moon, 3 days past first quarter, will set at 2:10 tomorrow morning.
Low in the south as it gets dark is the red giant star Antares. It lies at the heart of Scorpius the scorpion. Its name means Rival of Mars, because it has the same hue as the red planet. In Mars case the color comes from iron oxide, rust. In Antares case it has a cool surface temperature, relatively speaking, of 7,000 degrees Fahrenheit (3,660 K). As a red giant star Antares is near the end of its life, though compared to the Sun it is young – possibly 12 million years old. At that age the Sun was just getting started. Antares, with around 13 to 16 times the Sun’s mass, has already run out of fusible hydrogen in its core and has bloated out to double Mars’ orbit in size. Antares is 550 light years away and has a companion star in its system that looks greenish in contrast to Antares red. But, when Antares A, the red giant’s light is blocked, the companion looks bluish.
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
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