Ephemeris: 08/15/2023 – The Great Rift
This is Ephemeris for Tuesday, August 15th. Today the Sun will be up for 14 hours and 3 minutes, setting at 8:48, and it will rise tomorrow at 6:46. The Moon, 1 day before new, will rise at 6:41 tomorrow morning.
Once one finds the Milky Way which is pretty hard to miss this month, it becomes obvious that the Milky Way is split lengthwise starting near Deneb, the northernmost star of the Summer Triangle, almost all the way to the Teapot of Sagittarius low in the south. That dark split is called the Great Rift. Galileo first discovered that the hazy clouds of the Milky Way we’re actually made of faint stars, so it was thought the dark areas were due to a lack of stars. The great 18th century astronomer William Herschel did star counts all over the sky with his telescope. A map drawn of the shape of the Galaxy shows the lack of distant stars in the direction of the Great Rift. It’s not really fewer stars, but interstellar clouds of dust blocking the light of stars behind 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.
The span of the Milky Way across the summer sky as seen in the free Stellarium app. Specifically August 15th at 10 pm from Northern Michigan. The Milky Way has been set to its maximum brightness to show as much detail as possible. It really isn’t that bright. The horizon is only delineated by the compass points. The dark clouds of the Great Rift are also visible. The Milky Way, in Stellarium, is photo-realistic. The triangle of three bright stars above center is the Summer Triangle, Specifically, clockwise from the top star: Vega, Altair and Deneb. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image.
William Herschel’s vision of the cross-section of the Milky Way from 1785, drawn by his sister and collaborator, Caroline Herschel. The Great Rift is seen as the gap between the fingers of stars on the right. Herschel thought the rift was caused by a lack of stars. Other than that, he got the flattened shape right, for what he could see within ten thousand light years. The center of the Milky Way lies 27,000 light years to the right. The spiral structure of the Milky Way wasn’t determined until the advent of radio telescopes in the mid-twentieth century.
Ephemeris: 08/14/2023 – August is the month to explore the Milky Way
This is Ephemeris for Monday, August 14th. Today the Sun will be up for 14 hours and 6 minutes, setting at 8:50, and it will rise tomorrow at 6:44. The Moon, 2 days before new, will rise at 5:35 tomorrow morning.
Now is the time the summer Milky Way is displayed to its fullest to the southern horizon. We have a week and a half before the Moon begins to encroach on our dark skies after 10 pm. City folk come to our area and are sometimes fooled by the brightness and expanse of the Milky Way and think it’s a cloud. Yes, those are clouds indeed, but they are clouds of stars. Binoculars will begin to show them to be millions of stars, each too faint to be seen individually to the eye, but whose combined glow give the impression of a luminous cloud. Binoculars are the ideal tool to explore the Milky Way. Objects still too fuzzy can be checked out with a telescope to reveal their true nature. The dark nights of August and September are my favorites.
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 span of the Milky Way across the summer sky as seen in the free Stellarium app. Specifically August 15th at 10 pm from Northern Michigan. The Milky Way has been set to its maximum brightness to show as much detail as possible. It really isn’t that bright. The horizon is only delineated by the compass points. The dark clouds of the Great Rift are also visible. The Milky Way, in Stellarium, is photo-realistic. The triangle of three bright stars above center is the Summer Triangle, Specifically, clockwise from the top star: Vega, Altair and Deneb. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image.
Ephemeris: 08/11/2023 – The Perseid meteor shower will reach its peak tomorrow night to early Sunday morning
This is Ephemeris for Friday, August 11th. Today the Sun will be up for 14 hours and 14 minutes, setting at 8:54, and it will rise tomorrow at 6:41. The Moon, 3 days past last quarter, will rise at 2:32 tomorrow morning.
The Perseid meteor shower at its peak and will be visible all night tomorrow. It won’t have to compete with the Moon until after 3:30 am Sunday morning. The meteors will be seen all over the sky, However Perseid meteors can be backtracked to a spot below the W shaped constellation of Cassiopeia, in the area of the constellation Perseus. As the night progresses, the radiant point will be rising higher in northeast. So lay down on a blanket in a dark location, keep mosquito repellent handy, dress warmly, because the ground and air will be chilly and dewy. Bring some hot coffee or chocolate to drink. And enjoy up to 60 meteors an hour at the peak in the morning. They will be near peak all weekend.
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 Dome of the sky for the night of August 12th and 13th, 2023 at 10:30 PM for northern Michigan. The Perseid radiant is in the northeast and fairly low in the sky, and marked in yellow with the caption PerR. It will continue to rise in the northeast throughout the night. The constellation names are abbreviated. Their full names can be found here. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image. Created using my LookingUp app.
The cool thing about viewing the meteor shower early in the evening is that the meteoroids enter the Earth’s atmosphere at a grazing angle, so they seem to last longer and have longer trains. I remember one early evening meteor traveling down the Milky Way, like it was a highway.
The Dome of the sky for August 12th and 13th, 2023 at 3 AM for northern Michigan. The Perseid radiant is in the northeast, much higher in the sky, and marked in yellow with the caption PerR. The constellation names are abbreviated. Their full names can be found here. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image. Created using my LookingUp app.
Binoculars come in handy to view the luminous trains that the brightest Perseids leave behind for a short time.
Ephemeris: 08/10/2023 – The Perseid meteor shower will reach its peak early Sunday morning
This is Bob Moler with Ephemeris for Thursday, August 10th. Today the Sun will be up for 14 hours and 17 minutes, setting at 8:56, and it will rise tomorrow at 6:40. The Moon, 2 days past last quarter, will rise at 1:43 tomorrow morning.
Back before astronomers recognized the major meteor shower that occurs at this time of year, the streaks of light in the sky of “falling” or “shooting” stars were called, by Christians, the Tears of Saint Lawrence, who was martyred on this day in the year 258. The bits of comet debris, ranging from the size of sand grains to that of a pea, hit our atmosphere at 38 miles (59 kilometers) per second and quickly vaporize due to friction, causing the streak of light we call a meteor. They are called the Perseids since they appear to come from the constellation of Perseus, located in the northeastern sky. They will be best seen Saturday night and into Sunday morning, with rates of up to one a minute, on average, especially in the early morning hours.
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 Dome of the sky for the night of August 12th and 13th, 2023 at 10:30 PM for northern Michigan. The Perseid radiant is in the northeast and fairly low in the sky, and marked in yellow with the caption PerR. It will continue to rise in the northeast throughout the night. The constellation names are abbreviated. Their full names can be found here. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image. Created using my LookingUp app.
The Dome of the sky for August 12th and 13th, 2023 at 3 AM for northern Michigan. The Perseid radiant is in the northeast, much higher in the sky, and marked in yellow with the caption PerR. The constellation names are abbreviated. Their full names can be found here. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image. Created using my LookingUp app.
Remember, the meteors only seem to come from the radiant. They will appear all over the sky! The meteors of a shower travel in parallel paths, like train tracks, disappearing to a point in the distance.
Ephemeris: 08/09/2023 – Let’s find out where the naked-eye planets have wandered off to this week
This is Ephemeris for Wednesday, August 9th. Today the Sun will be up for 14 hours and 19 minutes, setting at 8:57, and it will rise tomorrow at 6:39. The Moon, 1 day past last quarter, will rise at 1:04 tomorrow morning.
Let’s find out where the naked-eye planets have wandered off to this week. Venus is gone, setting too close to sunset. It will pass between the Earth and the Sun on the 13th, and be visible before sunrise by the end of the month. Mars and Mercury, though technically in the evening sky and like Venus also appear too close to the Sun to be spotted. Mars will pass behind the Sun in November. The other two naked eye planets are in the morning sky. Appearing at 5:45 am, which is roughly 55 minutes before sunrise, tomorrow morning, Jupiter will be high in the southeast, Saturn will be lower in the southwest. And tomorrow morning, the waning crescent Moon will be midway up the sky in the east.
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
Saturn, low in the east-southeast at 11 pm, or about 2 hours after sunset, along with nearby zodiacal constellations. Click or tap on the image to enlarge it. Created using Stellarium and GIMP.
Jupiter Saturn and the Moon are seen at 5:45 tomorrow morning, August 10, 2023, about 55 minutes before sunrise. Also shown are the zodiacal constellations and Orion. The native peoples of our area, the Anishinaabe, called Orion the Winter Maker. So enjoy summer while it lasts, because and relatively few months it’s going to be all over, and Orion will be in the evening sky and winter will be here. Click or tap on the image to enlarge it. Created using Stellarium and GIMP.
Telescopic Saturn and Jupiter (north up) as they would be seen in a small telescope, with the same magnification, Saturn at 11 pm, the 9th and Jupiter at 5:45 am August 10, 2023. Apparent diameters: Saturn 18.87″, its rings 43.96″; Jupiter 41.02″. Saturn and Jupiter are approaching us, so their apparent diameters are growing. The ” symbol means seconds of arc (1/3600th of a degree). Click or tap on the image to enlarge it. Created using Cartes du Ciel (Sky Charts).
The Moon as it might appear in binoculars or telescope with selected features labeled tomorrow morning, August 10, 2023. Created using Stellarium, LibreOffice Draw for labels, and GIMP for the GIF animation.
The naked-eye planets and the Moon at sunset and sunrise on a single night, starting with sunset on the right on August 9, 2023. The night ends on the left with sunrise on the 10th. Venus is not in the sky at either sunset or sunrise, being south of the Sun. Large images can be truncated on the right. Click or tap on the image to enlarge and display the complete image. Created using my LookingUp app and GIMP.
Ephemeris: 08/08/2023 – What the indigenous peoples of the northern Great Lakes thought of Scorpius
This is Ephemeris for Tuesday, August 8th. Today the Sun will be up for 14 hours and 22 minutes, setting at 8:59, and it will rise tomorrow at 6:37. The Moon, at last quarter today, will rise at 12:32 tomorrow morning.
Scorpius the scorpion is now seen low in the southern sky in the at 10 pm. To me, the stars here make a very good scorpion. Scorpius was invented by the people of the Middle East, where scorpions are plentiful. The Anishinaabek native peoples of our area, however, saw here one of their legendary hero figures, Nenabozho. In the sky, the arc of four stars at the front of the scorpion and to the right of the bright star Antares is his bow. He is shooting an arrow toward the receding Great Panther or Curly Tail a constellation of spring whose curl of a tail is the head of the constellation Leo, now lost in the evening twilight in the west. Nenabozho was a hero in their creation stories, and a trickster who was sometimes seen as a rabbit.
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.
Ephemeris: 08/07/2023 – Sagittarius, centaur or teapot?
This is Bob Moler with Ephemeris for Monday, August 7th. Today the Sun will be up for 14 hours and 25 minutes, setting at 9:00, and it will rise tomorrow at 6:36. The Moon, 1 day before last quarter, will rise at 12:06 tomorrow morning.
Looking due south and low in the sky at 11 pm, now is one of my favorite asterisms, the Teapot of the constellation Sagittarius. Sagittarius, classically, represents a centaur with a bow and arrow aimed at the heart of the constellation Scorpius to its west. I can find the bow and arrow here, but the half man, half horse figure of the centaur eludes me. However, the stout little teapot of the children’s song is quite obvious, with its base, lid on top, handle to the left and the spout to the right. To make things more realistic, the bright Milky Way seems to rise like steam from its spout. The Teapot is an asterism, an informal constellation. As the night goes on, the Teapot moves westward and appears to tilt, pouring its tea on the southwestern horizon.
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
Sagittarius-Teapot finder animation for 11 pm, August 7, 2023. I’ve omitted all the lines in Sagittarius except the teapot stars from Stellarium, so there are more lines connecting the stars, most too far south to really spot easily from our latitude (45 degrees north). Click or tap on the image to enlarge it. Created using Stellarium and GIMP.
Named stars that are shown in the image above are Nunki, from an ancient tablet of thirty stars – The proclaimer of the sea. This is because the next four constellations to the east are water constellations: Capricornus, the sea goat; Aquarius, the water bearer; Pisces the fish; and Piscis Australis, the southern fish. Antares, in Scorpius, is of course the Rival of Mars, due to its reddish hue, and Mars passes Antares regularly on its journey through the Zodiac. An archer has to have his bow. Kaus Australis is the southern bow star. The star above that is Kaus Media, the middle bow star. And the star above and left of that is Kaus Borealis, the northern bow star. The constellation art that comes with Stellarium doesn’t match up with the stars of the bow.
The five stars on the left side of the Teapot is another asterism called the Milk Dipper.
Sagittarius in a short time exposure with added annotations. This would be later in the evening, around midnight. 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. These will be easily visible in binoculars. Credit Bob Moler.
Ephemeris: 08/04/2023 – Star party tonight if it’s clear
This is Ephemeris for Friday, August 4th. Today the Sun will be up for 14 hours and 32 minutes, setting at 9:04, and it will rise tomorrow at 6:33. The Moon, 3 days past full, will rise at 11:02 this evening.
The Grand Traverse Astronomical Society will be hosting a star party tonight at Northwestern Michigan College’s Joseph Rogers observatory from 10:00 and midnight. If it’s clear, there will be at least a good solid hour of relatively dark sky to view the wonders beyond the solar system between 10 and 11 pm tonight before the bright moon rises. Saturn should be spotted by 11 pm. Low in the east southeast. Though Saturn will be fuzzy due to all the Earth’s atmosphere we have to look through to see it, it will still be a great sight. Astronomers don’t consider Saturn to be an evening planet yet. To be an evening planet, it must rise before sunset. The observatory is located south of Traverse City, MI on Birmley Road between Keystone and Garfield roads.
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
Some of the GTAS members’ telescopes set up behind the observatory for the star party. There’s a 16-inch telescope in the dome above. The dome at ground level is set up for to transmit images for a Zoom connection with a 14-inch telescope. When Saturn and the Moon rise, they will only be visible from the 16-inch telescope in the big dome.
Ephemeris: 08/03/2023 – What is a rogue planet?
This is Bob Moler with Ephemeris for Thursday, August 3rd. Today the Sun will be up for 14 hours and 35 minutes, setting at 9:06, and it will rise tomorrow at 6:32. The Moon, 2 days past full, will rise at 10:40 this evening.
Did you ever hear of something called a rogue planet? A rogue planet is an exoplanet without a star, wandering through interstellar space. A planet could be ejected from its planetary system through interaction with another planet, or maybe it’s in a multiple star system and usually the body with the lease mass loses and can be ejected from the system. Another way to create a rogue planet is to have a planet being created like a star but without enough mass to build it up and be left with too little mass to ignite the hydrogen within its core to create helium and thus begin to shine. Rogue planets are detectable by gravitational microlensing, causing a background star inline with the rogue planet and the Earth to briefly brighten. Rogue planets can be detected and studied because they are relatively warmer than the 3
Kelvin Cosmic Microwave Background. The James Webb Space Telescope is an ideal tool to study them. There may be more rogue planets than stars in the Milky Way.
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.
This has been extensively modified from the presentation in the radio program.
Addendum
Ephemeris: 08/02/2023 – Let’s find out where the naked-eye planets have wandered off to this week
This is Bob Moler with Ephemeris for Wednesday, August 2nd. Today the Sun will be up for 14 hours and 37 minutes, setting at 9:07, and it will rise tomorrow at 6:31. The Moon, 1 day past full, will rise at 10:15 this evening.
Let’s find out where the naked-eye planets have wandered off to this week. Venus is gone, setting too close to sunset. It will pass between the Earth and the Sun on the 13th, and be visible before sunrise by the end of the month. Mars and Mercury, though technically in the evening sky and like Venus, appear too close to the Sun to be spotted. Mars will pass behind the Sun in November. The other two naked eye planets are in the morning sky. Appearing at 5:45 am, which is roughly 45 minutes before sunrise, tomorrow morning, Jupiter will be high in the southeast, while Saturn will be lower in the southwest. And tomorrow morning Saturn will be just above the bright waning gibbous Moon.
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
Large images like this are sometimes truncated to the right. Enlarging the image will restore the whole image.
