10/31/2022 – Ephemeris – The perfect Halloween star

This is Bob Moler with Ephemeris for Halloween, Monday, October 31st. Today the Sun will be up for 10 hours and 13 minutes, setting at 6:32, and it will rise tomorrow at 8:20. The Moon, 1 day before first quarter, will set at 12:02 tomorrow morning.

Not all the ghosts and goblins out tonight will be children. One is out just about 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 the name before astronomers discovered what was really wrong with it. They found out that it does a slow wink about every two days, 21 hours because Algol is two stars that eclipse each other. Her next evening wink will be dimmest at 10:25 p.m. November 19th.*

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

*For the broadcast, the source for the Algol minimum brightness time was the Stellarium app. For whichever date the sky is displayed for and Algol is clicked on, among the data for the star that is displayed is next minimum light. However, in double-checking the times with those posted in Sky & Telescope magazine after I recorded the program, it turns out to be 3 hours 46 minutes early, so minimum light would be at 1:36 am on November 17th. At the time given then, the eclipse would just be starting. The actual first eclipse minimum in the evening in November would be at 10:25 pm on the 19th. I hope it’s clear on the night of the 16/17th to see which prediction is right. In the past, S&T was accurate, or accurate enough.

Perseus, Cassiopeia, Andromeda with Algol finder animation for Autumn evenings. Click on the image to enlarge it. Created using Stellarium and GIMP.

Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius. Note that the captions in the image are as seen in a mirror. Early star representations were painted on a globe, a celestial sphere, so the stars and constellations were shown as seen from the outside. A God’s eye view. Early printed star charts simply kept the convention. I reversed the image, so it is seen from inside the celestial sphere. An Earthly view to match the sky as we see it. The image was found with the article on Algol on Wikipedia.

Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky

10/28/2022 – Ephemeris – Mars is turning around this weekend

This is Bob Moler with Ephemeris for Friday, October 28th. Today the Sun will be up for 10 hours and 21 minutes, setting at 6:37, and it will rise tomorrow at 8:16. The Moon, 3 days past new, will set at 8:39 this evening.

This Sunday the 30th, the planet Mars will cease its normal eastward motion in relation to the stars, and backtrack to the west for a while. The instant Mars stops its eastward motion, it is said to be stationary. The backtracking is called retrograde motion, which was hard for ancient astronomers to explain because they thought the Earth was not moving and in the center of the universe. And the planets moved in uniform circular motion. So said the Greeks, because they thought that things in the heavens were perfect, not like the imperfect things of the Earth. Mars was a hard case. Its motion was definitely not uniform or circular. To Copernicus, the retrograde motion meant that the Earth was a planet passing another planet in their race around the Sun.

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

Mars retrograde path from October 29, 2022 to January 11, 2023 against the stars of Taurus the bull. It will be at opposition on December 7, and actually closest to the Earth on November 30 at 50.61 million miles or 81.45 million kilometers. In the upper right is the beautiful Pleiades star cluster, also known as the Seven Sisters. Below and right is the V shaped star cluster that represents the face of Taurus the bull, with the bright red star Aldebaran as the bull’s angry red eye. That V of stars is called the Hyades, who in mythology were the half sisters to the Pleiades. Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts) and GIMP.

10/27/2022 – Ephemeris – Trying to spot the young Moon tonight

This is Bob Moler with Ephemeris for Thursday, October 27th. Today the Sun will be up for 10 hours and 24 minutes, setting at 6:38, and it will rise tomorrow at 8:15. The Moon, 2 days past new, will set at 7:55 this evening.

The Moon is again making its appearance in the evening sky as a thin crescent. The crescent appearance is because the moon is mostly between the Earth and the Sun. So we are seeing mostly its night side, with just a sliver of it being sunlit. But the Moon has the Earth in its sky, which is quite big and bright, much brighter than the Moon in our skies. And when the Moon’s phase is thin, the Earth, having the opposite phase, will be a nearly full gibbous orb. The Earth illuminates the Moon’s night side with earthlight. We call it earthshine, when the whole Moon appears faintly inside the crescent. It’s also known more poetically as the “Old moon in the new moon’s arms.” If you’re not sure, because the effect is faint, check it out in binoculars. The effect should last another night.

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

An old picture of mine overexposing the crescent Moon to bring out earthshine. The moon was a wider crescent than it will appear to be tonight.

10/26/2022 – Ephemeris – Let’s see where the naked-eye planets have wandered off to this week

This is Bob Moler with Ephemeris for Wednesday, October 26th. Today the Sun will be up for 10 hours and 27 minutes, setting at 6:40, and it will rise tomorrow at 8:14. The Moon, 1 day past new, will set at 7:21 this evening.

Let’s see where the naked-eye planets have wandered off to this week. Jupiter and Saturn will be visible this evening, in the east-southeast and south-southeast respectively, as soon after sunset as it will be dark enough to see them, which would be by 7:45 pm. Jupiter is seen against the stars of Pisces the fish, while Saturn is spotted in the eastern end of Capricornus the sea goat. The red planet Mars, though a morning planet, will rise tonight at 9:15 pm in the northeast. It’s located between the tips of the long horns of Taurus the bull. By seven tomorrow morning, the red planet Mars will be high in the southwestern sky, above the winter constellation of Orion. Mars has traveled about as far east as it will get for a while. It will head back westward after Sunday.

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

Jupiter and Saturn with label animation for 8 pm tonight, October 26, 2022. Click on the image to enlarge it. Created using Stellarium and GIMP.

Though Mars is a morning planet, since it is in the sky at sunrise, perhaps the best time to vies it is in the evening after it rises in the east-northeast at 9:15 pm. By 11 pm, as seen here, Mars should be high enough to present a decent image in a telescope. Click on the image to enlarge it. Created using Stellarium.

Telescopic views of Saturn Jupiter and Mars (north up) as they would be seen in a small telescope, with the same magnification. The image of Mars doesn’t show it, but the white north polar cap will appear at the top or north limb of Mars. Saturn and Jupiter are shown at 8 pm, Mars at 11 pm. Apparent diameters: Saturn 17.41″, its rings 40.55″; Jupiter 48.16″. Mars 14.58″. Mars’ distance is 59.7 million miles (96.2 million kilometers). The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on October 26, 2022. The night ends on the left with sunrise on the 27th. Click on the image to enlarge it. Created using my LookingUp program and GIMP.

10/25/2022 – Ephemeris – This eclipse season starts with a partial solar eclipse, but not for us

“But not for us” means not for Michigan in the United States. This is a script, as always, for a local radio program. Which also mentions the midterm election day, two weeks from now, which coincides with the total lunar eclipse that morning. I’ll have an Ephemeris Extra post before the lunar eclipse, which looks into the next few lunar and solar eclipses visible in Michigan and the United States.

This is Ephemeris for Tuesday, October 25th. Today the Sun will be up for 10 hours and 30 minutes, setting at 6:41, and it will rise tomorrow at 8:12. The Moon is new today, and won’t be visible.

The Moon will be visible in a negative way for some folks at this time. There is a partial solar eclipse in progress now for parts of Europe, Asia and Africa. So that thing blocking the northern part of the Sun for them will be the Moon. Being a partial eclipse means that an eclipse season has started, and we should have a lunar eclipse in about two weeks, when the Moon is full. There sure is, and it’s visible from here. In exactly two weeks, there will be. In the early morning hours of November 8th, Election Day, a total eclipse of the Moon. And if you’re standing outside the polling place waiting for the polls to open at 7 am, and it’s clear, and you have a view to the west, the partially eclipsed Moon will still be visible. That will be the ending partial phase of the eclipse.

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

Map for the area on the Earth where the partial solar eclipse of October 25, 2022, will be visible. Credit: NASA/GSFC, Fred Espenak.

10/24/2022 – Ephemeris – Finding Pisces the fish

This is Bob Moler with Ephemeris for Monday, October 24th. Today the Sun will be up for 10 hours and 33 minutes, setting at 6:43, and it will rise tomorrow at 8:11. The Moon, 1 day before new, will rise at 8:18 tomorrow morning.

High in the southeast at 9 p.m. are the four bright stars of the Great Square of Pegasus, the upside down flying horse. Lying along the left and bottom sides of the great square is the constellation of Pisces the fish, one of the constellations of the Zodiac that lie along the path of the Sun, Moon and planets. Even though the constellation is called the fish, the fish themselves are not well represented in the stars. What can be traced in the stars is the rope, that’s tied to their tails, anchored at the extreme southeastern part of the constellation. The right or western end of Pisces is the asterism, or informal constellation, of the Circlet. A loop of 5 stars, the rope around the tail of one of the fish, or the fish itself. Jupiter is seen against the stars of Pisces in the evening, the rest of this and early next year.

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

Pisces finder animation looking south-southeast with Jupiter at 9 pm tonight, October 24, 2022. Created using Stellarium and GIMP.

10/21/2022 – Ephemeris – Lots of transient astronomical activity this weekend

This is Bob Moler with Ephemeris for Friday, October 21st. Today the Sun will be up for 10 hours and 41 minutes, setting at 6:48, and it will rise tomorrow at 8:07. The Moon, halfway from last quarter to new, will rise at 4:44 tomorrow morning. | We have several astronomical events happening tonight and over the weekend. The Orionid meteor shower may still be at peak, appearing tonight between 11 pm and moonrise tomorrow morning. Up to 20, and maybe more, meteors per hour may be spotted just prior to moonrise. Tomorrow Venus will be in superior conjunction with the Sun, the passing behind, though not directly behind the Sun, and thus entering the evening sky. It will be a month or so for Venus to separate itself from the Sun’s glare to be spotted in the early evening. Finally, on Sunday Saturn will end its retrograde or westward movement against the stars of Capricornus and resume moving eastward, its normal motion around our sky.

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 Orionid meteor shower radiant. The radiant rises at 11 p.m., so the meteors will be visible from then into morning twilight. Despite the location of the radiant, the meteors will b e seen all over the sky. However, true Orionids can be traced back to the radiant point. This chart is from another year. This year, bright Mars would be at the top center of the image. Created using Stellarium.

Venus near Superior conjunction through the Solar and Heliospheric Observatory (SOHO) LASCO C2 Coronagraph. The white circle inside the occulting disk is the diameter of the Sun’s photosphere, the disk we see of the Sun in white light. Launched in 1995, SOHO has been in halo orbit around the Sun-Earth L1 Lagrange point ever since.

Saturn stationary animation showing it with and without annotations. The fine, folded line with tick marks is Saturn’s path. The tick marks are at 10-day intervals. Saturn starts out in retrograde motion, heading westward or to the right. On October 23rd, it slows and stops that motion. It begins to head back eastward in its normal prograde motion to the left. Outer planets like Saturn, Jupiter, Mars and the rest exhibit retrograde motion when the Earth in effect passes them on the same side of the Sun. Click on the image to enlarge it slightly. Created using Cartes du Ciel (Sky Charts), LibreOffice Draw, and GIMP.

10/20/2022 – Ephemeris – Halley’s Comet returns… in little bitty pieces

This is Bob Moler with Ephemeris for Thursday, October 20th. Today the Sun will be up for 10 hours and 44 minutes, setting at 6:49, and it will rise tomorrow at 8:06. The Moon, 3 days past last quarter, will rise at 3:36 tomorrow morning.

Halley’s Comet is back! (Pronounced Hawley’s) Well sorta. In the form of the Orionid meteor shower. Bits of Halley’s Comet from previous passes by the Earth’s orbit make their twice-yearly show in our skies as these bits collide with the Earth’s atmosphere. Halley’s orbit passes close to the Earth’s orbit at points where the Earth is around May 6th and again near October 21st. Light dust and ionized gas get blown back into the tail of the comet. Heavier particles will roughly follow in the comet’s orbit. The radiant, a spot above the constellation Orion and below Gemini from which they will seem to come, will rise around 11 pm. So view them any time after that as their numbers will increase until the Moon rises both tonight and tomorrow nights.

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 Orionid Radiant is high in the south at 5 a.m. this weekend. Created using Stellarium.

Halley’s Comet orbit with the orbits of the inner planets showing the points at which the debris from the comet intersect with the Earth’s orbit, causing meteor showers. Click on the image to enlarge it. Diagram credit JPL Small-Body Database Browser with my annotations.

10/19/2022 – Ephemeris – Let’s search for the naked-eye planets for this week

This is Bob Moler with Ephemeris for Wednesday, October 19th. Today the Sun will be up for 10 hours and 47 minutes, setting at 6:51, and it will rise tomorrow at 8:04. The Moon, 2 days past last quarter, will rise at 2:29 tomorrow morning.

Let’s search for the naked-eye planets for this week. Jupiter and Saturn will be visible this evening, in the east-southeast and south-southeast respectively, as soon after sunset as it will be dark enough to see them, which would be by 7:45 pm. Jupiter is seen against the stars of Pisces the fish, while Saturn is spotted in the eastern end of Capricornus the sea goat. The red planet Mars, though a morning planet, will rise tonight at 9:41 pm in the northeast. It’s located between the tips of the long horns of Taurus the bull. By seven tomorrow morning, the red planet Mars will be high in the southwestern sky, above the winter constellation of Orion. Tiny Mercury might be spotted very low in the east around 7:30 am for the next few days.

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

Jupiter and Saturn in the evening finder animation for 9 pm tonight, October 19, 2022. Click on the image to enlarge. Created using Stellarium and GIMP.

Mars among the winter stars at 7 tomorrow morning, October 20, 2022. Click on the image to enlarge it. Created using Stellarium.

Waning crescent Moon labeled/unlabeled animation for 7 tomorrow morning, October 20, 2022. Created using Stellarium, LibreOffice Draw, and GIMP.

Telescopic views of Saturn Jupiter and Mars (north up) as they would be seen in a small telescope, with the same magnification. The image of Mars doesn’t show it, but the white north polar cap will appear at the top or north limb of Mars. Saturn and Jupiter are shown at 9 pm, Mars at 7 am. I do not show planets less than 10 seconds of arc in diameter, so Mercury is not shown. Apparent diameters: Saturn 17.61″, its rings 41.02″; Jupiter 48.82″. Mars 13.86″. Mars’ distance is 63.0 million miles (101.4 million kilometers). The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).

The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on October 19, 2022. The night ends on the left with sunrise on the 20th. Click on the image to enlarge it. Created using my LookingUp program and GIMP.

10/18/2022 – Ephemeris – The Great Andromeda Galaxy

Oct 18. This is Bob Moler with Ephemeris for Tuesday, October 18th. Today the Sun will be up for 10 hours and 50 minutes, setting at 6:52, and it will rise tomorrow at 8:03. The Moon, 1 day past last quarter, will rise at 1:22 tomorrow morning.

The closest large galaxy to our Milky Way galaxy is the Great Andromeda Galaxy, seen in the eastern sky when it gets dark. It is barely visible to the naked eye. To locate it, first find the Great Square of Pegasus high in the east, standing on one corner. The left star of the square is the head of the constellation Andromeda. Follow two stars to the left and a bit downward, then two stars straight up. The galaxy is near that last star as a small smudge of light. Binoculars are the best way to see it as a thin spindle of light. Visually through a telescope, one can see only the bright nucleus of the galaxy, that spans six Moon diameters in photographs. M 31* is its most well known catalog designation, and it’s two and a half million light years away.

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.

* M 31 is the 31st entry in French comet hunter Charles Messier’s catalog of fuzzy objects that can be mistaken for comets because they didn’t move in relation to the stars. It is a catalog of some of the brightest, what we call, deep sky objects: star clusters, nebulae, and galaxies. It is not a comprehensive catalog of these objects, since Messier was interested in comets.

Addendum

Andromeda animated finder, including the Great Andromeda Galaxy. I’ve added Cassiopeia that some folks use to find the galaxy. I start with the leftmost star of the Great Square of Pegasus that connects to Andromeda. I count off two stars on the lower curve because they are brighter than the upper curve. Then count two stars up. Next to that top star is a little smudge. That is the core of the Great Andromeda Galaxy. Click on the image to enlarge to full size. Created using Stellarium and GIMP.

Low resolution and exposure view of M 31, the Great Andromeda Galaxy, simulating what it looks like in binoculars. Credit mine.

M 31, The Great Andromeda Galaxy. This image really shows the red H II Regions intermixed with the dark dust lanes that delineate the galaxy’s spiral arms. H II or ionized hydrogen regions are illuminated by hot young stars that were born within them. Click on the image to enlarge it. Credit: Dan Dall’Olmo.

The moon superimposed on the Great Andromeda Galaxy, M31, for apparent size comparison. Created using Stellarium and the embedded image of the galaxy with that of the full Moon of October 31, 2020. M31 Image credit: Herm Perez: http://home.att.net/~hermperez/default.htm License: “Feel free to use these images, if you use them in a commercial setting please attribute the source.”

The Great Andromeda Galaxy is shown with two of its satellite galaxies, both elliptical. The nearly spherical one is M 32. The other one I knew and observed, in the 1950s, as NGC 205**. Even though Messier had described this object in 1773, he didn’t add it to his catalog. The suggestion that it be added as the last entry in Messier’s catalog was made in 1967 by Welsh amateur astronomer Kenneth Glyn Jones***

** NGC is the New General Catalogue of Nebulae and Clusters of Stars, and is not so new. It was published in 1888 by John Louis Emil Dreyer.

*** Source: messier-objects.com