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01/17/2022 – Ephemeris – Venus at dawn

January 17, 2022 Leave a comment

This is Ephemeris for Martin Luther King Day, Monday, January 17th. Today the Sun will be up for 9 hours and 15 minutes, setting at 5:31, and it will rise tomorrow at 8:14. The Moon, at full today, will rise at 5:04 this evening.

Should it be clear these mornings, the planet Venus should be visible in the 7 to 8 o’clock hour low in the southeast. Venus, in this position, was known to the ancient Greeks as Phosphoros the Light-bringer, or Hesphoros which means the same thing. That is also what another name for Venus the Morning Star meant. That of Lucifer, which became the name of the Devil, a fallen angel. However, in Roman mythology, Lucifer was the son of Aurora, the goddess of dawn. Now Venus, despite its beautiful and brilliant appearance in the sky, is in reality a hellish place. It has sulfuric acid clouds, a nightmarish surface temperature of 850 degrees Fahrenheit, and 90 plus times the Earth’s atmospheric pressure at its surface.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Venus, Mars and two bright stars in the morning

Venus, Mars and two bright stars in the morning at 7:30, around 45 minutes before sunrise. Venus will pass Mars on for the first time this year on February 12th, only to have Mars pass Venus back on March 15th. That’s 5 days before Venus reaches its greatest separation from the Sun, and begins to head back around the Sun. Click in the image to enlarge it. Created using Stellarium.

01/14/2022 – Ephemeris – Mayan civilization and the planet Venus

January 14, 2022 Leave a comment

This is Ephemeris for Friday, January 14th. Today the Sun will be up for 9 hours and 10 minutes, setting at 5:27, and it will rise tomorrow at 8:16. The Moon, 3 days before full, will set at 6:47 tomorrow morning.

The Mayan people of pre-Columbian Central America were diligent observers of the planet Venus. One of their few surviving records is the Dresden Codex. It counts through a long series of Venus’ 584 day cycles. The location of the Mayan cities are a lot closer to the equator than we are, so when Venus disappears as it moves between the Earth and the Sun as it did last weekend, it only disappeared for 8 days. For us, at our latitude, it can be a few days longer. So we should spot it on clear mornings next week in the southeast by 7:15 to 7:30 am. It will appear as a thin crescent in telescopes or even binoculars. Venus will stay in the morning sky until later this year, which will set it up to be a spectacular evening star next year.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Venus Cycle

Venus Cycle derived from John P Pratt who had another purpose for the diagram and annotated to include the day number of days in each phase. For my purposes, ignore points 1 and 4. The Mayan cycle starts with 7, the first appearance of Venus during the morning. Points 8 and 5 are the points where Venus is at greatest elongation from the Sun. Credit John P Pratt.

Venus section of the Dresden Codex

Pages of the Dresden Codex, produced by the Maya tracking Venus’ appearances in the skies over the Yucatán, for 104 years. The Dresden Codex is one of only 4 surviving Mayan Codices.

01/13/2022 – Ephemeris – The Moon, first target for a new telescope

January 13, 2022 Leave a comment

This is Ephemeris for Thursday, January 13th. Today the Sun will be up for 9 hours and 8 minutes, setting at 5:26, and it will rise tomorrow at 8:17. The Moon, halfway from first quarter to full, will set at 5:47 tomorrow morning.

The Moon is probably the first astronomical object owners of a new telescope look at. The first discovery is that it’s not that easy to find. Most telescopes produce an upside down or a mirror reversed image, so steering the telescope may take a bit of getting used to. The Moon is at its gibbous phase tonight, so it’s quite bright, and a lot of it doesn’t have much contrast except for the large dark gray areas, called seas. There’s no water in them, of course, but they are huge lava basins caused by large asteroid impacts in the early days of the Moon’s history. The best detail on the Moon is near the terminator, in the time before full moon, it is the sunrise line. There the shadows are longest, and the detail of craters are best seen.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Virtual Moon Atlas showing Moon for tonight

This is a great guide to the Moon called Virtual Moon Atlas for a computer, showing the Moon for any date and time. It’s a free app which runs natively on Windows, but also can run with emulators on Linux and macOS. I find it to be an amazing program. Check it out under Free Astronomical Software on the right of this page.

The other free app I use is Stellarium (See the right column). Zoom in enough, so the Moon fills the frame, and It will show labels to some of its features if clicked on.

01/10/2022 – Ephemeris – Venus starts a new cycle in the morning sky

January 10, 2022 Comments off

This is Ephemeris for Monday, January 10th. Today the Sun will be up for 9 hours and 3 minutes, setting at 5:22, and it will rise tomorrow at 8:18. The Moon, 1 day past first quarter, will set at 2:36 tomorrow morning.

Two days ago, Venus passed between the Earth and the Sun in an event called an inferior conjunction. Inferior has nothing to due to quality, but denotes the fact that Venus is passing between the Earth and the Sun. The other Venus conjunction is the superior conjunction when Venus passes the Sun on the far side. We should be able to spot Venus rather suddenly in the late 7 to 8 am hour in a few days. Its appearance seems sudden and is sometimes reported as a UFO. It sometimes surprises airport control tower officials, because it may look like an airplane coming in with its landing lights on. But it never lands. In its morning appearance, Venus is sometimes called the Morning Star or Lucifer.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

The Mayans of pre-Columbian Central America were meticulous observers of Venus, as is seen in one of their surviving books, the Dresden Codex. A Venus Cycle lasts 584 days, from first appearance in the morning sky, its heliacal rising, through its morning appearance, disappearance behind the Sun, through its evening appearance and disappearance on front of the Sun to the next heliacal rising. Astronomers call that it’s synodic period. Five Synodic periods equal almost exactly 8 years.

Venus 9 days after Inferior conjunction

Venus, 9 days after Inferior conjunction, next Monday morning. Venus will be just under 5 degrees above an unobstructed horizon at 7:30 am in northwest lower Michigan. Created using Stellarium.

12/16/2021 – Ephemeris – The brightest spot on the Moon

December 16, 2021 Comments off

This is Ephemeris for Thursday, December 16th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:03, and it will rise tomorrow at 8:14. The Moon, 2 days before full, will set at 6:53 tomorrow morning.

The Moon tonight is bright. The sunrise line or terminator on the moon is crossing the large gray plain called Oceanus Procellarum, the largest of the moon’s seas. These seas were figments of the first telescopic observers imagination. They are really huge impact basins into which interior lava flowed. On the upper left edge of the moon near the terminator is a bright spot visible in binoculars. In a telescope, it is a crater called Aristarchus. It is a fairly new crater, probably less than a billion years old. As a rule the brighter the crater the newer it is. Aristarchus is the brightest spot on the moon. Over the years, visual astronomers have seen hazes and bright spots from time to time in and near Aristarchus. Their cause is still a mystery.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Brightest spots on the nearly full Moon

The brightest spots on the Moon as they might appear tonight, December 16, 2021. This is not a photograph. But created using Stellarium, presumably from lunar satellite photographs that simulate the phase and shadows.

Oblique view of the crater Aristarchus from a lunar orbiting satellite

Oblique view of the crater Aristarchus from a lunar orbiting satellite. Credit: NASA/GSFC/Arizona State University.

12/14/2021 – Ephemeris – The Moon tonight will reveal more than you think

December 14, 2021 Comments off

This is Ephemeris for Tuesday, December 14th. Today the Sun will be up for 8 hours and 49 minutes, setting at 5:02, and it will rise tomorrow at 8:13. The Moon, halfway from first quarter to full, will set at 4:45 tomorrow morning.

The gibbous Moon tonight is revealing a bit more of itself. In binoculars the dark oval spot visible on the Moon’s right side is the Sea of Crises or Mare Crisium a small dark lava plain. The Moon’s rotation is quite uniform, however its orbit isn’t circular, so the Moon’s face seems to rock a bit back and forth over the month. It’s an effect called libration. And one way to track that is to note how close the Sea of Crises is to the edge of the Moon. Right now that sea is as far from the Moon’s right edge or limb as it gets, and reveals two other seas in the edge: Mare Marginis, the Border Sea, and Mare Smythi, Smith’s Sea.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Moon showing libration

The Moon showing Maria Marginis and Smythi past Mare Crisium at 9 pm tonight, December 14, 2021. Created using Stellarium.

Moon as seen if over Mare Marginis

The Moon, seen as if flying over the border area of what we could see from the Earth. To the left is the Moon’s near side. To the right is the far side to the terminator or sunset line. Created using Virtual Moon Atlas.

Both the Stellarium and Virtual Moon Atlas apps are free. Links to them are elsewhere on this page.

12/13/2021 – Ephemeris – The Geminid Meteor Shower reaches its peak tomorrow morning

December 13, 2021 Comments off

This is Ephemeris for Monday, December 13th. Today the Sun will be up for 8 hours and 50 minutes, setting at 5:02, and it will rise tomorrow at 8:12. The Moon, 3 days past first quarter, will set at 3:41 tomorrow morning.

Tomorrow morning we will have the chance to see near the peak of the Geminid meteor shower after the Moon sets. Some of its members can be seen tonight, in the bright moonlight. This shower is currently besting the Perseid meteor shower of August, with a predicted 120 meteors per hour tomorrow morning. The problems for us in viewing this fabulous shower, beside the bright Moon this year, are the cold temperatures and usually cloudy skies. The source of the Geminids was discovered in 1983. It is a probably burnt out comet with the asteroid designation 3200 Phaethon, which swoops down to only 13 million miles of the Sun. Some call it a rock comet. The Geminids were first seen in 1862.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Geminids radiant finder

An all sky view at 4 am, December 14th, 2021, showing the radiant for the Geminid meteor shower. The meteors will be seen all over the sky. Their trails, however, can be traced back to their radiant. The radiant is marked on the chart as GemR, near the star Castor in Gemini. The sky at that hour is that of the evening sky of early spring. Created using my LookingUp program.

For a list of constellation names to go with the abbreviations, click here.

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris, the North Star.
  • Follow the arc of the handle of the Big Dipper to the star Arcturus, then
  • Follow the spike to Spica.

12/10/2021 – Ephemeris – Our last look at Comet Leonard before it leaves forever*

December 10, 2021 Comments off

This is Ephemeris for Friday, December 10th. Today the Sun will be up for 8 hours and 52 minutes, setting at 5:02, and it will rise tomorrow at 8:10. The Moon, at first quarter today, will set at 12:25 tomorrow morning.

This is the day of the earliest sunset of the year. It doesn’t coincide with the shortest day because the Earth is moving faster in its orbit than average and getting ahead of its rotation a bit. Comet Leonard’s last appearance in the morning sky is tomorrow or Sunday before twilight overwhelms it. At 6:30 am it will be just a bit south of due east at azimuth 93 degrees and an altitude of 9 degrees, a bit less than the width of a fist held at arm’s length. When it gets into the evening sky, its track will take will be along the horizon from the southwest to the south. It will come very close to Venus, and I suspect that is what will alter its orbit slightly, so it will never return and end up becoming an interstellar comet.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

* After this weekend, the comet will enter the evening sky, but will hang quite low to the horizon in evening twilight as it passes Venus, heads southward and fades. It would best be viewed by observers in the Southern Hemisphere. It’s headed out of the solar system in a hyperbolic orbit.

Addendum

Comet Leonard 7 am, 12/11/21

Comet Leonard (C/2021 A1) finder chart for 7:00 am, December 11, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 22.1 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 7:15 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for December 10th. The star field will be shifting to the upper right each morning at 7:15 from the December 10th date at 7:15. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Created using Cartes du Ciel (Sky Charts).

12/09/2021 – Ephemeris – Comet Leonard and the Oort Cloud

December 9, 2021 Comments off

This is Ephemeris for Thursday, December 9th. Today the Sun will be up for 8 hours and 53 minutes, setting at 5:02, and it will rise tomorrow at 8:09. The Moon, 1 day before first quarter, will set at 11:14 this evening.

Comet Leonard will only be available to be spotted for the next two mornings. After that, it will be too close to the direction of the Sun to be spotted. It came in from hundreds of times the Earth’s distance from the Sun from a spherical area around the solar system call the Oort cloud. This area, proposed as a source of comets, was named after Dutch astronomer, Jan Oort, who hypothesized its existence. Near as we can tell, Comet Leonard had been falling toward the Sun for 40,000 years. Tomorrow morning the comet will be nearly 30 degrees below and a bit left of the bright star Arcturus from 6:00 to 7 am tomorrow morning. 30 degrees is three times the width of one’s fist held at arm’s length.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Comet Leonard 6 am 12-10-21

Comet Leonard (C/2021 A1) finder chart for 6:00 am, December 10, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 23.1 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 7:15 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for December 10th. The star field will be shifting to the upper right each morning at 7:15 from the December 10th date at 7:15. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. The tails shown here simply show the direction of the tail, which will be very short, if visible at all visually. Created using Cartes du Ciel (Sky Charts).

12/07/2021 – Ephemeris – This is the best week to view Comet Leonard

December 7, 2021 Comments off

This is Bob Moler with Ephemeris for Tuesday, December 7th. Today the Sun will be up for 8 hours and 55 minutes, setting at 5:02, and it will rise tomorrow at 8:07. The Moon, halfway from new to first quarter, will set at 8:43 this evening.

The evening sky between 5:45 and 7 pm will feature Venus, the crescent Moon, with dim Saturn above it and Jupiter all in the southwestern sky. Saturn will appear dim, only in the early part of that period, due to bright twilight. Saturn is about midway between Venus and Jupiter. In the morning sky, Comet Leonard continues to fall inward toward the Sun. It’s passing relatively close to the Earth, now about 29 million miles. It will pass its closest to on Sunday at about 21 million miles, at which time we’ll have a hard time spotting it in morning twilight. Comet Leonard will stay barely bright enough to spot in dark skies by really sharp-eyed observers without binoculars or a telescope. The rest of us will need optical aid.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

Comet Leonard finder 12/08/21 6:30 am

Comet Leonard (C/2021 A1) finder chart for 6:30 am, December 8, 2021. The comet’s tail may not be visible visually. The comet’s head, what astronomers call a coma, may appear as a large fuzzy spot. At that time it will be 26.7 million miles away, and will come within 21.7 million miles at its closest to us on the 12th. Created using Stellarium.

Comet Leonard (C/2021 A1) in the morning

Comet Leonard’s positions at 6:30 am on the dates indicated. The labels are Month-Day Total Magnitude. The star’s position relative to the horizon and the position of Mars are for November 27th. The star field will be shifting to the upper right each morning at 6:30 from the November 27th date at 6:30. Comets always appear dimmer than their magnitude suggests because they are extended objects, not points like stars. Also, comet magnitudes can be unpredictable. Created using Cartes du Ciel (Sky Charts). I’ve reversed the colors from previous printings of this image. Reprinted from my article in the Stellar Sentinel, the newsletter for the Grand Traverse Astronomical Society.