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09/15/2022 – Ephemeris – Finding Cassiopeia this time of year

September 15, 2022 Comments off

This is Ephemeris for Thursday, September 15th. Today the Sun will be up for 12 hours and 31 minutes, setting at 7:53, and it will rise tomorrow at 7:22. The Moon, 2 days before last quarter, will rise at 10:30 this evening.

In the northeastern sky is a letter W shaped constellation of Cassiopeia, the queen of Greek myth. I can’t say Cassiopeia is rising in the northeast, because it never sets for us in northern Michigan. This time of year it skirts above the northern horizon during the daytime. One of Cassiopeia’s claims to historical astronomical fame is that it’s the location of Tycho’s Star, a supernova discovered in 1572 by Danish astronomer Tycho Brahe, the last of the great astronomers prior to the invention of the telescope. Tycho was able to prove that the temporary phenomenon was actually a star in the heavens, disproving the Greek notion that the heavens were changeless and perfect. The Chinese had already known that, calling them Guest Stars.

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

Cassiopeia finder animation

Cassiopeia finder animation for 10 pm tonight, September 15th. One cannot miss the distinctive W. Created using Stellarium.

Tycho's Supernova 1574A

Tycho’s Supernova 1574A, as simulated in Stellarium for mid-November 1572.

Tycho's Supernova remnant seen in x-rays

Tycho’s Supernova remnant, seen in x-rays by the orbiting Chandra X-ray Observatory. Credit: NASA / Chandra

08/23/2022 – Ephemeris – A king’s shield in the sky

August 23, 2022 Comments off

This is Bob Moler with Ephemeris for Tuesday, August 23rd. Today the Sun will be up for 13 hours and 40 minutes, setting at 8:35, and it will rise tomorrow at 6:55. The Moon, halfway from last quarter to new, will rise at 3:42 tomorrow morning.

In the southern sky between the Teapot of Sagittarius below and Aquila the Eagle with its southernmost star of the Summer Triangle lies Scutum the shield of John Sobieski, the Polish king who stopped the advance of the Turks at Kalenberg in 1683. The Polish half of me is very proud. Scutum is one of two official constellations which are related to real persons. The other one is Coma Berenices, a hank of the Egyptian Queen Berenice’s hair. However, the stars here are so dim and embedded in the glow of the Milky Way as to be nearly impossible to discern. Scutum lies in one of the richest portions of the Milky Way, wonderful to scan with binoculars and telescopes for star clusters and nebulae or clouds of dust and gas.

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

I think of Scutum as an area of the Milky Way between Aquila and Sagittarius. Created using Stellarium and GIMP.

08/19/2022 – Ephemeris – Finding the small constellations near the Summer Triangle

August 19, 2022 Comments off

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.

Coathanger finder

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.

08/16/2022 – Ephemeris – Scanning Sagittarius with binoculars

August 16, 2022 Comments off

This is Bob Moler with Ephemeris for Tuesday, August 16th. Today the Sun will be up for 14 hours to the minute, setting at 8:46, and it will rise tomorrow at 6:47. The Moon, 3 days before last quarter, will rise at 11:15 this evening.

The Moon has left the evening sky, so let’s take another look at the constellation of Sagittarius. Its bright stars make a follow the dots image of a stout little teapot. In, around and above the teapot is a wealth of nebulae, which are clouds of gas and dust and clusters of stars. Stars are born in bunches from a cloud of gas. When enough stars are born, their stellar winds blow away the nebulosity leaving a star cluster. Use a pair of binoculars or a very low power telescope and just wander around and above the teapot, including and especially the spout on the right side. In binoculars, star clusters appear fuzzy like nebulae, however a small telescope with magnification of 20 times should resolve most of them.

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

Annotated Sagittarius photograph

Sagittarius in a short time exposure with added annotations. The “M” designations are objects in Charles Messier’s catalog created in the latter half of the 18th century. LSSC is the Large Sagittarius Star Cloud, SSSC is the Small Sagittarius Star Cloud. Labels are to the right of the objects they name. Credit Bob Moler.

This is the short radio program version of the August 8, 2022, Ephemeris Extra post Wandering through Sagittarius

Ephemeris Extra – Wandering through Sagittarius

August 8, 2022 Comments off

Annotated Sagittarius photograph

Sagittarius in a short time exposure with added annotations. The “M” designations are objects in Charles Messier’s catalog created in the latter half of the 18th century. LSSC is the Large Sagittarius Star Cloud, SSSC is the Small Sagittarius Star Cloud. Credit Bob Moler.

Sagittarius is seen low in the south in August. It’s between Scorpius to the west, and Capricornus, rising in the southeast. The name Sagittarius simply means archer. It doesn’t describe the fact that the archer isn’t just any old bloke with a bow and arrow, but is, indeed, a centaur, one of the two in the list of constellations. The other, Centaurus, is too far south to be seen from Michigan. And whose brightest star, Alpha Centauri, is in the closest star system to our solar system.
Centaurs, as a rule, were a rowdy bunch, the ancient Greek equivalent to a modern motorcycle gang. However, the centaur depicted by Sagittarius can be thought to be Chiron, though it can also be ascribed to Centaurus. Chiron was learned, a teacher and physician. I’ve noticed that in some artist’s depictions of Chiron, he is teaching Achilles how to use the bow and arrow. He also taught medicine to Asclepius, the great physician, who is seen in the heavens as the constellation Ophiuchus, above and right of Sagittarius.
What most of us see in the stars here is maybe a bow drawn to shoot at the heart of Scorpius, or a stout little teapot as in the children’s song. It even has the Milky Way seeming to rise from the spout like steam. The teapot rises in the southeast as if standing upright, and as the night wears on, it rises and move westward, slowly tilting to pour out its tea on the southwestern horizon.
The area of Sagittarius and the Milky Way is a fantastic part of the sky to explore with binoculars or a low power telescope on moonless nights. At the head of this post is a photograph of Sagittarius and the Milky Way taken from my home, with lines and labels. It’s somewhat spoiled by the sky glow from Chum’s Corner, a small commercial center 3.6 miles away, from the lower left. Most binoculars will show open or galactic star clusters as fuzzy spots like nebulae, which are fuzzy because they are clouds. The older globular star clusters require larger amateur telescopes to resolve.
I’ve only pointed out one in the image, that’s M22, whose designation, we have fun with at star parties at the Sleeping Bear Dunes National Lakeshore, since the road M22 runs through the park. Which came first? That’s easy, Charles Messier cataloged his 22nd object before Michigan was a state or even had roads. Well, maybe there were a few, around Detroit and Sault Ste. Marie, back when the major “roads” were the Great Lakes, and the rest Indian trails.
A telescope, even a small one, will resolve open clusters, showing individual stars. Telescopes will show the shapes of nebulae if they are bright enough.
One nebula with a distinctive shape is M17. The descriptive name I first knew it as was the Omega Nebula, and also the Horseshoe Nebula. To me, it never looked like either. It looked like a check mark, or a somewhat short necked swan. And it also goes by those names too. The planetarium program I use a lot, Stellarium, also calls it the Lobster nebula. I’m not much for seafood, but it doesn’t look like a lobster, or maybe I’m not hungry enough.
M16, is the Eagle Nebula. It has an associated star cluster. My eyes are drawn to the star cluster. The nebulosity is very faint, and I usually can’t see it. Part of the nebula was famously photographed by the Hubble Space Telescope and called the Pillars of Creation. In actuality, they are the Pillars of Destruction as they are being blown away by the stellar winds of the star cluster.
M8 is the Lagoon Nebula, it also has an associated star cluster. In telescopes, it is crossed by a narrow dust cloud suggestive of a lagoon. Nearby M20 is the Trifid nebula, which has a low surface brightness and can easily be missed. It is crossed by three narrow dust clouds dividing it into three, or on closer inspection, four wedges.
These just scratch the surface. So with or without optical aid wander through the celestial wonders and star clouds of Sagittarius. You have August and September to do it in the evening before they set for another year.

Based on an article I wrote for the August 2022 issue of the Stellar Sentinel, the Newsletter of the Grand Traverse Astronomical Society.

07/19/2022 – Ephemeris – How to find the constellations of the man with the snake

July 19, 2022 Comments off

This is Ephemeris for Tuesday, July 19th. Today the Sun will be up for 15 hours and 7 minutes, setting at 9:22, and it will rise tomorrow at 6:16. The Moon, 1 day before last quarter, will rise at 12:52 tomorrow morning.

The red star Antares shines in the south at 11 pm, in the constellation of Scorpius. In the area of sky above lies a large constellation of faint stars called Ophiuchus, the serpent bearer. The constellation shape is like a large tilted bell, which reminds me of the head, shoulders and arms of a fellow that’s holding the snake, like a weight lifter pulling up a heavy barbell. The serpent he’s holding is Serpens, the only two-part constellation in the heavens. The head rises to Ophiuchus’ right, and the tail extends up to the left. In Greek legend Ophiuchus represents a great physician, educated by the god Apollo, and the centaur Chiron, who is also found in the stars as Sagittarius, now rising in the south-southeast below and left of him.

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

Ophiuchus finder animation

Ophiuchus finder animation for mid-July at 11 pm. Created using Stellarium and GIMP.

07/18/2022 – Ephemeris – How to find the celestial eagle

July 18, 2022 Comments off

This is Bob Moler with Ephemeris for Monday, July 18th. Today the Sun will be up for 15 hours and 8 minutes, setting at 9:23, and it will rise tomorrow at 6:15. The Moon, 2 days before last quarter, will rise at 12:33 tomorrow morning.

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, a group of three bright stars that dominate the eastern 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 toward the eagle.

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

Aquila finder animation

Animated Aquila finder chart, also showing Cygnus the swan. The named stars are the stars of the Summer Triangle. Created using Stellarium.

Actual Aquila

Annotated and animated photograph taken of Aquila August 13, 2018 during the Perseid meteor shower. Alas, no Perseids in this photograph. The clouds of the Great Rift are easily visible. The red tinge of the image was due to the smoke haze from the wildfires in the western states. Taken by me and processed using Registax and GIMP.

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

July 15, 2022 Comments off

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

Cygnus finder animation

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.

06/28/2022 – Ephemeris – Finding the celestial harp

June 28, 2022 Comments off

This is Ephemeris for Tuesday, June 28th. 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 is new today, and won’t be visible.

High in the east at 11 p.m. can be found a bright star just above a small, narrow, but very distinctive parallelogram of stars. They are the stars of the constellation Lyra the harp. The bright star is Vega, the 4th or 5th brightest nighttime star*, and currently the topmost star of the Summer Triangle. To the Romans, the star Vega represented a falling eagle or vulture. Apparently they never made the distinction between the two species. It is a pure white star and serves as a calibration star for color and brightness. In the evening, it is the top-most star of the Summer Triangle. The harp, according to Greek mythology, was invented by the god Hermes. The form of the harp, in the sky, is as he had invented it: by stretching strings across a tortoise shell. Hermes gave it to his half-brother Apollo, who in turn gave it to the legendary musician Orpheus.

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.

*Vega’s rival for the fourth spot on the brightness list is Arcturus to it’s west. Wikipedia’s source says that Arcturus is slightly brighter. Stellarium’s source says Vega is brighter. The difference is a few hundredths of a magnitude. However, they are of different colors. Vega is pure white, while Arcturus is yellow-orange because it has a cooler surface temperature than Vega. Check them out for yourself.

Addendum

Annimated Lyra finder chart

Animated Lyra finder chart. The lyre image not supplied by Stellarium but is from The World’s Earliest Music by Hermann Smith, Figure 60, A Project Gutenberg E-Book, and captioned “The Chelys or Greek Tortoiseshell Lyre”. The three names stars are the stars of the Summer Triangle in the eastern sky these evenings of late June. Created using Stellarium.

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

June 27, 2022 Comments off

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

Summer Triangle finder animation

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.