Archive
10/13/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, October 13th. Today the Sun will be up for 11 hours and 5 minutes, setting at 7:01, and it will rise tomorrow at 7:57. The Moon, 1 day past first quarter, will set at 1:00 tomorrow morning.
Let’s search for the naked-eye planets for this week. Venus should be visible in the southwestern evening twilight by 7:20 tonight. It will set at 8:37 pm. By 7:45 pm, Jupiter will be spotted in the south-southeastern sky. The Jupiter should be easy to spot at that hour. Saturn will be dimmer, and to its right. It will be above and left of the Moon tonight. They will be visible for a while after midnight in the southwest, with Saturn setting first at 1:31 am, and Jupiter following at 2:52. Saturn’s rings are a beautiful sight in a telescope of even modest power, but the planet will appear tiny. Jupiter’s 4 brightest moons are spread out, two on each side of the planet tonight. They might all be visible in binoculars.
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
Venus seen in twilight at 7:20 pm, about 20 minutes after sunset on October 13, 2021. Created using Stellarium.
Jupiter, Saturn and the Moon at 7:45, about 45 minutes after sunset in this view to the south-southeast. Click on the image to enlarge it. Created using Stellarium.
The slight gibbous Moon as it might appear tonight in binoculars or small telescope. It appears here right side up as it would appear in the sky at 9 pm. Created using Stellarium.
Telescopic views of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening at 9 pm, October 13, 2021. Apparent diameters: Venus, 21.15″, 56.8% illuminated; Saturn 17.29″, its rings 40.27″; Jupiter, 44.63″. 9 pm is also the best time to find the Great Red Spot on Jupiter’s face. Io will be in transit of the face of Jupiter until 7:53 pm. After that, Io will be increasing its distance from the planet. 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 13, 2021. The night ends on the left with sunrise on the 14th. It looks like Mercury will be far enough from the Sun next week to spot in the morning. Click on the image to enlarge it. Created using my LookingUp program.
10/07/2021 – Ephemeris – The loneliest star in the sky
This is Bob Moler with Ephemeris for Thursday, October 7th. Today the Sun will be up for 11 hours and 23 minutes, setting at 7:11, and it will rise tomorrow at 7:49. The Moon, 1 day past new, will set at 8:06 this evening.
There’s a bright star that appears for only seven and a half hours on autumn nights. It’s appearance, low in the south-southeast at 9 p.m., is a clear indication of the autumn season. 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 appears to be quite alone low in the sky. The dimness of the constellation’s other stars and location close to the horizon make the other stars hard to spot. The Earth’s thick atmosphere near the horizon reduces their brightness by a factor of two or more, so Fomalhaut, one of the brightest stars in the sky, keeps a lonely vigil in the south.
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
Fomalhaut at 9 pm, October 7, 2021. This year it has two bright planets relatively nearby, By they’re just passing through, albeit slowly. Normally the closest first magnitude star to Fomalhaut is Altair, the southernmost of the Summer Triangle stars. Created using Stellarium.
10/06/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, October 6th. Today the Sun will be up for 11 hours and 26 minutes, setting at 7:13, and it will rise tomorrow at 7:48. The Moon is new today, and won’t be visible.
Let’s search for the naked-eye planets for this week. Venus should be visible in the southwestern evening twilight by 7:45 tonight. It will set at 8:52 pm. By 8 pm, Jupiter will be spotted in the south-southeastern sky. The Jupiter should be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. They will be visible into the morning hours, with Saturn setting first at 1:58 am, and Jupiter following at 3:20. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power the rings won’t appear separated from the planet, so Saturn will look like an elliptical disk. Jupiter’s 4 brightest moons are spread out, three on one side, and one on the other. They might all be visible in binoculars tonight.
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
Venus in evening twilight at 7:45 pm, about a half hour after sunset. Created using Stellarium.
Jupiter and Saturn at 8 pm, about 45 minutes after sunset tonight, October 6, 2021. Created using Stellarium.
Telescopic views of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening at 8 pm, October 6, 2021. Apparent diameters: Venus, 19.81″, 59.8% illuminated; Saturn 17.48″, its rings 40.73″; Jupiter, 45.55″. 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 6, 2021. The night ends on the left with sunrise on the 7th. Click on the image to enlarge it. Created using my LookingUp program.
09/29/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, September 29th. Today the Sun will be up for 11 hours and 47 minutes, setting at 7:26, and it will rise tomorrow at 7:39. The Moon, 1 day past last quarter, will rise at 12:40 tomorrow morning.
Let’s search for the naked-eye planets for this week. Venus should be visible in the southwestern evening twilight by 7:45 tonight. It will set at 8:59 pm. By 8 pm, Jupiter will be spotted in the southeastern sky. The Jupiter should be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. They will be visible into the morning hours, with Saturn setting first at 2:26 am, with Jupiter following at 3:49. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power the rings won’t appear separated from the planet, so Saturn will look like an elliptical disk. Jupiter’s four brightest moons are spread out, two on each side. They all might be visible in binoculars tonight.
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
Venus in evening twilight at 7:45 pm, about a half hour after sunset tonight, September 29, 2021. Created using Stellarium.
Jupiter and Saturn in the southeast at 8 pm. Created using Stellarium.
Low magnification view of the waxing crescent Moon as it would appear at 6:30 am tomorrow, September 30, 2021. Created using Stellarium.
Telescopic views of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening at 8 pm, September 29, 2021. Apparent diameters: Venus, 18.65″, 62.6% illuminated; Saturn 17.68″, its rings 41.18″; Jupiter, 46.41″. 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 September 29, 2021. The night ends on the left with sunrise on the 30th. Click on the image to enlarge it. Created using my LookingUp program.
09/24/2021 – Ephemeris – Capricornus, home this season to Jupiter and Saturn
This is Bob Moler with Ephemeris for Friday, September 24th. Today the Sun will be up for 12 hours and 3 minutes, setting at 7:35, and it will rise tomorrow at 7:33. The Moon, halfway from full to last quarter, will rise at 9:26 this evening.
Nearly 2000 years ago the southernmost of the constellations of the zodiac was Capricornus the water goat. That’s why the latitude on the Earth where the Sun is overhead on the winter solstice is called the Tropic of Capricorn. Not anymore, Sagittarius, one constellation west, has that honor today*. Capricornus is large, but made up of dim stars. To me, it looks like a 45 degree isosceles triangle, long side up, but which all the sides are sagging. The constellation is found low in the south at 10 to 11 p.m. The image that is supposed to be represented by the stars is that of a goat whose hind quarters are replaced by a fish’s tail, not a mermaid but a mer-goat. This autumn, Jupiter is at the left end of Capricornus, with Saturn on the right.
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 reason for the shift is lunisolar precession, which I talked about yesterday.
Addendum
Capricornus w/Jupiter & Saturn finder animation for 10 pm, September 24, 2021. Created using Stellarium and GIMP.
09/22/2021 – Ephemeris – Autumn starts this afternoon and a look at the naked-eye planets
This is Bob Moler with Ephemeris for Wednesday, September 22nd. Today the Sun will be up for 12 hours and 9 minutes, setting at 7:39, and it will rise tomorrow at 7:31. The Moon, 2 days past full, will rise at 8:43 this evening.
Here on Earth, the season of fall will begin at 3:21 this afternoon. Let’s search for rest of the naked-eye planets for this week. Venus should be visible in the southwestern evening twilight by 8 o’clock tonight. It will set at 9:08 pm. By 8:15 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. They will be visible into the morning hours, with Saturn setting first at 2:55 am, with Jupiter following at 4:19. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power the rings won’t appear separated from the planet, so Saturn will look like an elliptical disk.
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
Venus in twilight at 8 pm, or about 20 minutes after sunset, tonight, September 22, 2021. An animation showing its altitude at that time of 10 degrees (about the width of your fist held at arm’s length). Created using Stellarium and GIMP.
Waning gibbous Moon, about 15 minutes after rising as it might be visible in binoculars or small telescope. Created using Stellarium.
Telescopic views of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 8 pm, Jupiter and Saturn at 10 pm, September 22, 2021. Apparent diameters: Venus, 17.61″, and 65.3% illuminated; Saturn 17.86″, its rings 41.61″; Jupiter, 47.20″. 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).
Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on September 22, 2021. The night ends on the left with sunrise on the 23rd. Click on the image to enlarge it. Created using my LookingUp program.
09/15/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, September 15th. Today the Sun will be up for 12 hours and 30 minutes, setting at 7:52, and it will rise tomorrow at 7:23. The Moon, 2 days past first quarter, will set at 1:59 tomorrow morning.
Let’s search for the naked-eye planets for this week. Venus should be visible in the western evening twilight before 8:15 tonight. It will set at 9:19 pm. By 8:30 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Both these planets will be to the left of the bright gibbous Moon. They will be visible for most of the night, with Saturn setting first at 3:24 am, with Jupiter setting at 4:50 tomorrow morning. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power, the rings won’t appear separated from the planet, so Saturn will look like an elliptical spot. Most of Jupiter’s 4 brightest moons can even be spotted in binoculars.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.
Addendum
Venus in evening twilight at 8:15 tonight, about 20 minutes after sunset, September 15, 2021. Created using Stellarium.
Jupiter Saturn and the Moon at 8:30 tonight, about 40 minutes after sunset, September 15, 2021. Created using Stellarium.
Low magnification view of the Moon tonight. The large crater Clavius is seen at the south (bottom) of the Moon. The crater Copernicus is seen near the left edge of the Moon, the sunrise terminator. Created using Stellarium.
Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 8:30 pm, September 15, 2021. Apparent diameters: Venus, 16.70″ 68% illuminated; Saturn 18.03″, its rings 42.00″; Jupiter, 47.88″. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).
Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on September 15, 2021. The night ends on the left with sunrise on the 16th. Click on the image to enlarge. Created using my LookingUp program.
09/08/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, September 8th. Today the Sun will be up for 12 hours and 52 minutes, setting at 8:06, and it will rise tomorrow at 7:14. The Moon, 2 days past new, will set at 9:16 this evening.
Let’s search for the naked-eye planets for this week. Venus should be visible in the western evening twilight before 8:30 tonight. It will set at 9:41 pm. By 8:30 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Both these planets will be visible for most of the night, with Saturn setting first at 3:53 am, with Jupiter setting at 5:21 tomorrow morning. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power, the rings won’t appear separated from the planet, so Saturn will look like an elliptical spot. Most of Jupiter’s 4 brightest moons can even be spotted in binoculars.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.
Addendum
Venus and the Moon in evening twilight at 8:30 pm tonight, September 8, 2021. This is about 25 minutes after sunset. Created using Stellarium.
The thin crescent Moon as it might appear with earth shine in binoculars at 8:30 pm tonight, September 8, 2021. Created using Stellarium.
Jupiter and Saturn in the southeast at 8:30 pm, about a half hour after sunset tonight, September 8, 2021. Created using Stellarium.
Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 8:30 pm, and the other two at 10 pm, September 8, 2021. Apparent diameters: Venus, 15.88″ 70% illuminated; Saturn 18.19″, its rings 42.36″; Jupiter, 48.43″. Jupiter’s moons will slowly approach the planet from our viewpoint overnight. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).
Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on September 8, 2021. The night ends on the left with sunrise on the 9th. Click on the image to enlarge it. Created using my LookingUp program.
09/01/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, September 1st. Today the Sun will be up for 13 hours and 13 minutes, setting at 8:18, and it will rise tomorrow at 7:06. The Moon, 2 days past last quarter, will rise at 1:57 tomorrow morning.
Let’s search for the naked-eye planets for this week. Venus should be visible in the western evening twilight before 9 tonight. It will set at 9:41 pm. By 9 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Both these planets will be visible for most of the night, with Saturn setting first at 4:22 am, with Jupiter setting at 5:53 tomorrow morning. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power, the rings won’t appear separated from the planet, so Saturn will look like an elliptical spot. Most of Jupiter’s 4 brightest moons can be spotted in binoculars.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.
Addendum
Venus in twilight at 8:45 pm, about 1/2 hour after sunset tonight, September 1, 2021. Created with Stellarium.
Jupiter and Saturn in the southeast about three quarters of an hour after sunset. Created using Stellarium.
The waning crescent Moon as it might be seen in binoculars or low magnification telescope at 6 am tomorrow morning, September 2, 2021.
Created using Stellarium.
Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 9 pm, and the other two at 11 pm, September 1, 2021. Apparent diameters: Venus, 15.16″, 73% illuminated; Saturn 18.32″, its rings 42.67″; Jupiter, 48.83″. Jupiter’s moons Io and Europa will slowly approach the planet over the morning hours. Io will be occulted by the planet around 4:05 am (08:05 UT). Europa will begin its transit across the face of the planet around 5:04 am (09:04 UT). 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). Jovian satellite event times determined from Stellarium.
Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on September 1, 2021. The night ends on the left with sunrise on the 2nd. Click on the image to enlarge. Created using my LookingUp program.
Note: Mars and Mercury are too close to the direction of the Sun to be visible from Northern Michigan. However, Mercury will be easily visible far south of here and into the Southern Hemisphere.
08/25/2021 – Ephemeris – Let’s search for the naked-eye planets for this week
This is Ephemeris for Wednesday, August 25th. Today the Sun will be up for 13 hours and 34 minutes, setting at 8:31, and it will rise tomorrow at 6:58. The Moon, 3 days past full, will rise at 10:20 this evening.
Let’s search for the naked-eye planets for this week. Venus should be visible in the western evening twilight before 9 tonight. It will set at 9:53 pm. By 9 pm, Jupiter and Saturn will be seen low in the southeastern sky. The brighter Jupiter will be easy to spot at that hour. Saturn will be dimmer, but a bit higher and to its right. Both these planets will be visible for most of the night, with Saturn setting first at 4:52 am, with Jupiter setting at 6:26 tomorrow morning. Saturn’s rings can be seen in a spotting scope of about 20 power magnification. Though at that power, the rings won’t appear separated from the planet, so Saturn will look like an elliptical spot. Most of Jupiter’s 4 brightest moon can be spotted in binoculars.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.
Addendum
Venus in evening twilight tonight, August 25, 2021 at 9 pm, about 1/2 hour after sunset. Created using Stellarium.
Jupiter and Saturn in the southeast at 9:30 pm tonight, August 25, 2021, about 45 minutes after sunset. Created using Stellarium.
The Moon as it might appear tonight in binoculars or a small telescope at 11:30 pm, about an hour after it rises tonight, August 25, 2021. Created using Stellarium.
Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening. Venus at 9:15 pm, and the other two at 11 pm, August 25, 2021. Apparent diameters: Venus, 14.51″ 75% illuminated; Saturn 18.43″, its rings 42.93″; Jupiter, 49.06″. Jupiter’s moons Io and Ganymede will slowly separate after 11 pm. 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).
Planets and the Moon at sunset and sunrise of a single night, starting with sunset on the right on August 25, 2021. The night ends on the left with sunrise on the 26th. Click on the image to enlarge. Created using my LookingUp program.
Bob Moler's Ephemeris Blog 