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12/02/2020 – Ephemeris – A look at the naked-eye planets for this week

December 2, 2020 Leave a comment

This is Ephemeris for Wednesday, December 2nd. Today the Sun will be up for 9 hours and 1 minute, setting at 5:03, and it will rise tomorrow at 8:02. The Moon, 2 days past full, will rise at 6:51 this evening.

Let’s look for the naked-eye planets for this week. Jupiter and Saturn are both low in the southwestern sky from 7 to 8 pm. Jupiter is the very bright one. Above and left it by 2 degrees or 4 moon widths will be dimmer Saturn. They are slowly closing, so they will cross paths on the evening of December 21st and be seen in the same telescope field that evening. Jupiter will set first tonight at 8:20 with Saturn following at 8:32. Quite high in the southeast at that hour will be Mars, still in Pisces. Mars’ distance is increasing to 60.2 million miles (97.0 million km) away. Mars will set at 3:27 tomorrow morning. Brilliant Venus will rise at 5:40 am in the east-southeast as it retreats slowly towards the Sun, but actually it’s heading around behind the Sun.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Evening planets and the Moon

The evening planets with the Mon rising at 7 pm tonight December 2, 2020. Click on the image to enlarge. Created using Stellarium.

Binocular Moon

The Moon as it might be seen tonight at 9 pm, December 2, 2020. Created using Stellarium.

The planets as seen in a telescope (north up) with the same magnification for the night of November 25/26, 2020. Times of the display are: Jupiter, Saturn and Mars, 7 pm; Venus, 6:30 am. Apparent diameters: Jupiter, 34.28″; Saturn, 15.63″, rings, 36.41″; Mars, 14.27″; and Venus, 11.57″. Mars also displays an enlargement showing surface detail. Mars was closest to the Earth this go-a-round on October 6. The ” symbol means seconds of arc (1/3600th of a degree.)  Click on the image to enlarge. Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on December 2, 2020. The night ends on the left with sunrise on the 3rd. I’m afraid that the labels for Jupiter and Saturn will overlap, since the planets are getting very close. Click on the image to enlarge. Created using my LookingUp program.

11/30/2020 – Ephemeris – We’ve entered an eclipse season

November 30, 2020 Leave a comment

This is Bob Moler with Ephemeris for Monday, November 30th. Today the Sun will be up for 9 hours and 4 minutes, setting at 5:03, and it will rise tomorrow at 8:00. The Moon, at full today, will rise at 5:22 this evening.

This morning we had a slight eclipse of the Moon, where the Moon entered only the southern part of the Earth’s penumbral or partial shadow. On December 14th, at the next new moon there will be a total eclipse of the Sun that will be visible from South America. We are now in an eclipse season which lasts about 35 days. In that time two or rarely three eclipses can be fit in. The next eclipse season is 5 months and 18 days away in late May and early June 2021. Then there will be, for Michigan, the start of a lunar eclipse visible just before sunrise on May 26th and the end of a solar eclipse visible at sunrise on June 10th. Those two eclipses will just be teasing us. Our next nearby total solar eclipse is less than three and a half years away on April 8, 2024.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Explaining eclipse seasons, NASA/JPL

A diagram showing eclipse seasons. Though only solar eclipses are shown, it also includes lunar eclipses. Three months later (actually only a month later) the shadows of each are either too far north or south to fall on the other. Click on the image to enlarge. Credit: NASA/JPL

11/27/2020 – Ephemeris – There will be a slight eclipse of the Moon Monday morning

November 27, 2020 Comments off

This is Ephemeris for Native American Heritage Day, Friday, November 27th. Today the Sun will be up for 9 hours and 9 minutes, setting at 5:05, and it will rise tomorrow at 7:57. The Moon, 3 days before full, will set at 6:02 tomorrow morning.

Early Monday morning there will be a penumbral eclipse of the Moon. It’s not much of an eclipse to look at, but it is an eclipse to open the last eclipse season of this year. I’ll have more on that Monday, but the lunar eclipse on Monday will a slight one, where no part of the Moon disappears into the Earth’s inner shadow. The top part of the Moon will look a bit darker than the bottom part for a time, that’s all. The Earth and the Moon are illuminated by the Sun, and it isn’t a point light source. Your shadow isn’t sharp. The fuzziness at the edge of your head’s shadow on the ground in the sunlight is your penumbra. The maximum part of the eclipse will be at 4:44 am (09:44 UT)with the effect seen within a half hour of that time. The effect is best seen with sunglasses to dim the Moon.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Penumbral eclipse maximum

The maximum of the penumbral lunar eclipse at 4:44 am EST (9:44 UT) Monday, November 30, 2020. The upper right part of the Moon will have a dusky appearance. The effect should be visible from about 4:15 to 5:15 am (09:15 to 10:15 UT). I find it’s best to view the Moon with sunglasses to reduce the Moon’s glare to better see the effect. Created using Stellarium.

Penumbral lunar eclipse with earth's shadow

Penumbral lunar eclipse with Earth’s shadow at maximum. The outer ring is the outer edge of the penumbra the Moon’s outer shadow where so little sunlight is cut off as to not be discernible. The inner circle is the edge of the umbra, the darkest part of the Earth’s shadow, where almost 100% of the Sun’s light is cut off. The Moon will be in the western sky at this time, and its motion with respect to the Earth’s shadow is to the upper left. Created using Cartes du Ciel (Sky Charts).

11/26/2020 – Ephemeris – A look at Saturn (planet and god) in mythology

November 26, 2020 Comments off

This is Ephemeris for Thanksgiving Day, Thursday, November 26th. Today the Sun will be up for 9 hours and 11 minutes, setting at 5:05, and it will rise tomorrow at 7:55. The Moon, 4 days before full, will set at 4:59 tomorrow morning.

Over the next 25 days Jupiter and Saturn will draw together to be in conjunction. And like I said Tuesday, I don’t know what that means astrologically, since I don’t believe in that stuff. I find the universe quite indifferent to my fate or the fate of anything happening on the third rock. Saturn, which will seem to cross paths with Jupiter on the evening of December 21st, a few hours after winter starts is named after the Roman god of agriculture and periodic renewal among others. He is depicted carrying a scythe, and even today we see him as the Grim Reaper, and at the end of the year as Father Time. The Saturn is the Roman counterpart of the Greek Cronus a Titan, the bringer of old age. It’s a fitting name for the slowest of the naked-eye planets, known from antiquity, taking almost 30 years to shuffle its way around the Sun.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Saturn and rings

Saturn and rings from the Cassini spacecraft, plus the aurora oval in ultraviolet. Credit: NASA/JPL/Space Science Institute

A statuette of Cronus (Saturn) shown holding a scythe and an hour glass. Source: https://respuestas.tips/quien-es-cronos-en-la-mitologia-griega/

11/25/2020 – Ephemeris – Let’s look for the naked-eye planets for this week

November 25, 2020 Comments off

This is Ephemeris for Wednesday, November 25th. Today the Sun will be up for 9 hours and 12 minutes, setting at 5:06, and it will rise tomorrow at 7:54. The Moon, 4 days past first quarter, will set at 3:58 tomorrow morning.

Let’s look for the naked-eye planets for this week. Jupiter and Saturn are both low in the southwestern sky from 7 to 8 pm. Jupiter is the very bright one. Above and left will be dimmer Saturn. They are slowly closing, so they will cross paths on the evening of December 21st and be seen in the same telescope field that evening. Jupiter will set first tonight at 8:41 with Saturn following at 8:56. Off in the southeast at that hour will be Mars above the bright gibbous Moon tonight. Mars’ distance is increasing to 55.6 million miles (89.6 million kilometers) away. Mars will set at 3:47 tomorrow morning. Brilliant Venus will rise at 5:21 am in the east-southeast as it retreats slowly toward, but actually around the back of the Sun.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Evening planets

Evening planets and the Moon for 7 pm tonight November 25, 2020. Click on the image to enlarge. Created using Stellarium.

The gibbous Moon

The gibbous Moon as it might be seen in binoculars this evening at 7 pm November 25, 2020. Created using Stellarium.

Venus in the morning

Venus and the morning constellations at 6:30 am tomorrow November 26, 2020. Created using Stellarium.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification for the night of November 25/26, 2020. Times of the display are: Jupiter and Saturn, 7 pm; Mars, 10 pm; Venus, 6:30 am. Apparent diameters: Jupiter, 34.76″; Saturn, 15.76″, rings, 36.72″; Mars, 15.45″, and Venus 11.85″. Mars also displays an enlargement showing surface detail. Mars was closest to the Earth this go-a-round on October 6. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on November 25, 2020. The night ends on the left with sunrise on the 26th. I’m afraid that the labels for Jupiter and Saturn will overlap, since the planets are getting very close. Click on the image to enlarge. Created using my LookingUp program.

11/24/2020 – Ephemeris – Next month’s conjunction of Jupiter and Saturn

November 24, 2020 Comments off

This is Ephemeris for Tuesday, November 24th. Today the Sun will be up for 9 hours and 14 minutes, setting at 5:06, and it will rise tomorrow at 7:53. The Moon, 3 days past first quarter, will set at 2:57 tomorrow morning.

Over the next 27 days Jupiter and Saturn will draw together to be in conjunction. I don’t know what that means astrologically, since I don’t believe in that stuff. It just means that Jupiter and Saturn lie near the same line of sight from the Earth. Though they will be almost as close as they get to each other, that won’t be that close. They were closest to each other earlier this month, at about 450 million miles (724 million kilometers). Jupiter is now about 525 million miles (845 million kilometers) away from us. Both, of course, are on the other side of the Sun from us. Jupiter, in its nearly 12 year orbit of the Sun laps the slower Saturn in it’s nearly 30 year orbit about every 20 years. It will do so again on November 5th of 2040.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Possible telescope view of Jupiter-Saturn conjunction 6 pm, December 21, 2020

Possible telescopic view of Jupiter-Saturn conjunction 6 pm, December 21, 2020. Created using Cartes du Ciel (Sky Charts).

Jupiter and Saturn along the same line of sight

Jupiter and Saturn along the same line of sight from the Earth on December 21, 2020. Created using my LookingUp program.

11/23/2020 – Ephemeris – Our Moon is different

November 23, 2020 Comments off

This is Bob Moler with Ephemeris for Monday, November 23rd. Today the Sun will be up for 9 hours and 16 minutes, setting at 5:07, and it will rise tomorrow at 7:52. The Moon, 2 days past first quarter, will set at 1:55 tomorrow morning.

The Earth’s Moon is different from most other moons. First it is very big when compared to the Earth. The Moon is a bit more than quarter the Earth’s diameter. Only Pluto’s moon Charon is larger compares to its primary, being half the size of Pluto. Most big moons orbit over their planet’s equator. Our Moon orbits the Earth close to the plane of Earth’s orbit of the Sun. That’s why the Moon is seen passing the planets each month. The Moon is too big to have been captured by the Earth in a chance flyby. The moon rocks brought back during Apollo showed that the Moon was made of the same crustal material as the Earth, so the impact theory was put forth that the Moon was the result of a collision of the Earth and a Mars sized body soon after they were formed.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The Moon's orbit vs the ecliptic

The Moon’s orbit (red) vs the ecliptic or plane of the Earth’s orbit (orange). The Moon’s orbit is tilted to the Earth’s orbit by 5 degrees. This is for 4:30 pm or a little more than a half hour before sunset. The black sky is due to removing atmospheric scattering in the program. Click on the image to enlarge. Created using Stellarium.

In the image note that the Moon’s orbit crosses the ecliptic just east of the Sun’s position. That crossing point is called the Moon’s descending node, since the Moon’s eastward motion will take it from north of the ecliptic to south of it. When the Sun is close to a node eclipses can occur. The ascending node is at the opposite side of the ecliptic so both solar and lunar eclipses occur in an eclipse season that lasts about a month.

An indeed there will be a penumbral eclipse of the Moon on the 30th, and a total solar eclipse for Chile and Argentina December 14th. The nodes don’t stay in one place, but they move westward, making one rotation around the ecliptic in 18.61 years. Since the nodes are moving westward it is called the regression of the nodes. So eclipse seasons occur about every 5 2/3 months, moving backwards in the calendar.

11/20/2020 – Ephemeris – Martian Trojan asteroid may have come from our Moon

November 20, 2020 Comments off

This is Ephemeris for Friday, November 20th. Today the Sun will be up for 9 hours and 22 minutes, setting at 5:09, and it will rise tomorrow at 7:48. The Moon, 1 day before first quarter, will set at 10:39 this evening.

The way gravity works there are several gravitational sweet spots called Lagrangian points between orbital bodies. Two of those points, 60 degrees ahead of and behind a planet in its orbit, are called L4 and L5. Bodies at these points are called Trojan asteroids. Because the first ones found in Jupiter’s orbit were named after warriors of the Trojan War. What was discovered recently was that one of the planet Mars’ L5 Trojans is not like the others. It has a different composition as analyzed by a spectrograph. It reflects light like the Earth’s Moon, while the others appear to have come from Mars itself. Perhaps an ejected piece of the Moon made it out to Mars orbit. We know small meteoroids can make it planet to planet, maybe huge chunks can make it too.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Martian Trojan asteroids

Mars and its Trojan asteroids including 101429 the asteroid that is spectroscopicly like the Moon. The other Trojans appear to have come from Mars itself. I tend to be a stickler for image accuracy: The Mars image is upside down and reversed, while the rest of the diagram is essentially correct other than being way out of scale. Credit Armagh Observatory and Planetarium (AOP) in Northern Ireland.

11/17/2020 – Ephemeris – Let’s look for the naked-eye planets for this week

November 18, 2020 Comments off

This is Bob Moler with Ephemeris for Wednesday, November 18th. Today the Sun will be up for 9 hours and 26 minutes, setting at 5:11, and it will rise tomorrow at 7:45. The Moon, halfway from new to first quarter, will set at 8:24 this evening.

Let’s look for the naked-eye planets for this week. Jupiter and Saturn are both low in the southwestern sky 7 to 8 pm. Jupiter is the very bright one. Above and left it will be the somewhat dimmer Saturn. They are near the Moon tonight. They are slowly closing, so they will cross paths on December 21st and be seen in the same telescope field that evening. Jupiter will set first tonight at 9:02 with Saturn following at 9:21. Off in the southeast at that hour will be Mars. Its distance is increasing to 51.5 million miles (82.9 million kilometers) away. Mars will set at 4:10 tomorrow morning. Brilliant Venus will rise at 5:03 am in the east-southeast as it retreats slowly toward the Sun. Close to ending its morning appearance now is Mercury which will rise at 6:15 am in the east.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Jupiter, Saturn and Moon in the early evening

Jupiter, Saturn and Moon low in the southwest at 7:30 pm tonight, November 18, 2020. Created using Stellarium.

Evening planets, Moon, ecliptic and zodiac in the evening

Evening planets, Moon, ecliptic and zodiac at 7:30 pm tonight November 18, 2020. Click on the image to enlarge. Created using Stellarium.

Venus and Mercury with the star Spica and Corvus in the morning

Venus and Mercury with the star Spica, the ecliptic (path of the Sun) and the constellation Corvus at 6:30 tomorrow morning November 19, 2020. Created using Stellarium.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification for the night of November 18/19, 2020. Times of the display are: Jupiter and Saturn, 7:30 pm; Mars, 10 pm; Venus, 6:30 am. Apparent diameters: Jupiter, 35.30″; Saturn, 15.91″, rings, 37.06″; Mars, 16.72″, and Venus 12.15″. Mars also displays an enlargement showing surface detail. Mars was closest to the Earth this go-a-round on October 6. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).

Planets and the Moon on a single night

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on November 18, 2020. The night ends on the left with sunrise on the 19th. I’m afraid that the labels for Jupiter and Saturn will overlap, since the planets are getting very close. Click on the image to enlarge. Created using my LookingUp program.

11/17/2020 – Ephemeris – The Pleiades in legends from different cultures

November 17, 2020 Comments off

This is Ephemeris for Tuesday, November 17th. Today the Sun will be up for 9 hours and 29 minutes, setting at 5:12, and it will rise tomorrow at 7:44. The Moon, 2 days past new, will set at 7:23 this evening.

Let’s look at how some other cultures saw the Pleiades, the star cluster that is seen in the eastern sky these evenings. To the Anishinaabe native peoples around here the Pleiades is the “Hole in the Sky” or the seven stones that are heated for the sweat lodge ceremony. To the Kiowa these were sister stars that had been whisked into the sky from the top of Devils Tower in Wyoming where they were threatened by a huge bear. In Norse mythology these were the goddess Freya’s hens. The name we know them by has rather misty origins. Some think the Greek name is from the mother of the seven sisters, Pleione. The Greek word for sail is similar to Pleiades, and it seems the appearance of the Pleiades in the morning sky saw the best sailing weather in the Mediterranean.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Devil's Tower

Seven maidens being attacked by a giant bear, having fled to the top of Devil’s Tower in Wyoming. Painting by Herbert Collins, https://www.nps.gov/deto.

The Pleiades, about what you'd see in binoculars.

The Pleiades, about what you’d see in binoculars, more than the 6 or 7 stars visible to the naked eye. The brighter stars are Freya’s Hens and also the Seven Sisters and Indian maidens. Credit Bob Moler.

Pleiades finder animation

Pleiades finder animation looking east about 8 pm in mid-November. Created using Stellarium.