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Archive for October, 2020

10/30/2020 – Ephemeris – The spookiest star in the sky

October 30, 2020 Comments off

This is Ephemeris for Friday, October 30th. Today the Sun will be up for 10 hours and 14 minutes, setting at 6:33, and it will rise tomorrow at 8:20. The Moon, 1 day before full, will set at 8:08 tomorrow morning.

With the COVID virus around probably the only spooky thing out tomorrow night will be the star Algol. It’s out every night actually. It’s name, Algol, is from the Arabic for Ghoul Star or Demon Star. The Chinese had a name for it that meant “piled up corpses”. 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 winking eye. The star got the name before astronomers found out what was wrong with it. They found out that it does a slow wink every two days, 21 hours. That’s because Algol is two stars that eclipse each other. Her next evening wink will be at its dimmest at 12:11 am November 13th. Remember, daylight time ends on Sunday.

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

Addendum

Algol at 7:30 p.m. on Halloween

Algol at 7:30 p.m. on Halloween, in a modern portrayal. Created using Stellarium.

Eclipsing Binary Star

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

Algol minima table

Algol Minima through November 24th 2020. Click on the image to enlarge. Eclipses are about 10 hours long with 5 hours of dimming and another 5 hours to regain brightness. Source: Insula Astra http://www.astropical.space/algol.php.

 

 

10/29/2020 – Ephemeris – A look at Bennu the asteroid

October 29, 2020 Comments off

This is Ephemeris for Thursday, October 29th. Today the Sun will be up for 10 hours and 17 minutes, setting at 6:34, and it will rise tomorrow at 8:18. The Moon, 2 days before full, will set at 7:06 tomorrow morning.

Tonight we will have Mars appearing above the bright gibbous Moon in the evening sky. Out in space NASA’s OSIRIS-REx spacecraft is still in the vicinity of the tiny asteroid Bennu. The asteroid is about 60 percent the distance between the Earth’s and Mars’ orbits, but on the far side of the Sun from us. This is why it will take 3 years to return the sample to the Earth. Bennu is small, only 743 feet (226.5 meters) in diameter. And is a rubble pile asteroid with lots of empty voids between the rocks. The sampler instead of stopping at the surface, punched into the asteroid surface a bit. Bennu was picked because is a potential hazardous asteroid and is a particularly primitive type of asteroid.

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

Addendum

Bennu and Earth showing distance

Inner Solar when OSIRIS REx took its sample from Bennu. Bennu’s official designation is 101955 Bennu. The number designation is the consecutive number it is given when placed on the official list of asteroids and dwarf planets when its orbit is determined. Notice that it was on the other side of the Sun. Credit NASA’s Eyes app.

The asteroid Bennu is 743 feet (226.5 meters) in diameter. It is a carbonaceous asteroid. OSIRIS-REX has already discovered water bearing clays on its surface. Credit NASA

10/28/2020 – Ephemeris – Let’s look for the naked-eye planets for this week

October 28, 2020 Comments off

This is Ephemeris for Wednesday, October 28th. Today the Sun will be up for 10 hours and 20 minutes, setting at 6:36, and it will rise tomorrow at 8:17. The Moon, 3 days before full, will set at 6:05 tomorrow morning.

Let’s look for the naked-eye planets for this week. Jupiter and Saturn are both low in the south-southwestern sky at 8 pm. Jupiter is the very bright one. Left and a bit above it will be the somewhat dimmer Saturn. They are closing slowly, so they will cross paths on December 21st and be in the same telescope field that evening. Jupiter will set first tonight at 11:08 with Saturn following at 11:37. Off in the east-southeast at that hour will be Mars. Since the it was closest 22 days ago its distance has increased to 42.0 million miles (67.6 million km) away. Brilliant Venus will rise at 5:12 am in the east as it retreats slowly toward the Sun. We’ll have a big jump backwards in rise and set times next week when standard time returns.

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

Addendum

Evening planets

The evening planets and the Moon at 8 pm tonight, October 28, 2020. Click on the image to enlarge. Created using Stellarium.

Binocular Moon

The waxing gibbous Moon tonight October 28, 2020 as it might appear in binoculars or a low power telescope. Created using Stellarium.

Venus in the morning

The morning planet Venus visible at 7 am October 29, 2020 with some of the stars of morning. Click on the image to enlarge. Created using Stellarium.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification for the night of October 28/29, 2020. Times of the display are: Jupiter and Saturn, 8 pm; Mars, 11 pm; Venus, 7 am. Apparent diameters: Jupiter, 37.26″; Saturn, 16.42″, rings, 38.25″. Mars, 20.27″, and Venus 13.29″. 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 October 28, 2020. The night ends on the left with sunrise on 29th. Click on the image to enlarge. Created using my LookingUp program.

10/27/2020 – Ephemeris – NASA’s cup runneth over with asteroid bits

October 27, 2020 Comments off

This is Ephemeris for Tuesday, October 27th. Today the Sun will be up for 10 hours and 23 minutes, setting at 6:37, and it will rise tomorrow at 8:16. The Moon, half way from first quarter to full, will set at 5:04 tomorrow morning.

One week ago the NASA’s OSIRIS Rex spacecraft unfolded its sampling arm, and folded up it solar panels so as to look like a one legged stork landing and touched a small level patch of small jagged rocks on the tiny asteroid Bennu. A nitrogen bottle was triggered to blow soil and small rocks into a cylindrical container which created quite a blizzard of small rocks. A flap on the collection device was supposed to close, keeping the collected bits in, but was propped open by a large rock, so some of the contents started to leak out. Now flight controllers must gently maneuver the collector into the return canister without losing too much of the contents. The sample canister is expected to return to Earth in 2023.

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

Addendum

Artist depiction OSIRIS-REx TAG (Touch and Go)

Artist depiction OSIRIS-REx TAG (Touch and Go) from video. Credit NASA.

Animated GIF of the actual sample collection

Animated GIF of the actual sample collection TAG (Touch and Go). Credit NASA.

For more information go to https://www.nasa.gov/osiris-rex

 

10/26/2020 – Ephemeris – Why does everyone want to go to the Moon’s south pole?

October 26, 2020 Comments off

This is Bob Moler with Ephemeris for Monday, October 26th. Today the Sun will be up for 10 hours and 26 minutes, setting at 6:39, and it will rise tomorrow at 8:14. The Moon, 3 days past first quarter, will set at 4:01 tomorrow morning.

Why are the United States and other countries interested in the south pole of the Moon? Two reasons: Water and power. The Moon’s axial tilt to the Earth’s orbit is only a degree and a half. And I’ve seen a mountain peak at the south pole of the Moon sticking out in sunlight in a telescope on a crescent moon, with black all around it. While most of the Moon gets two weeks of daylight and another two of night, that peak is probably always in sunlight. And on the Moon there’s no atmosphere to diminish the strength of the Sun when its low in the sky. And there’s the floors of craters that have never seen the Sun where water ice and other volatile compounds from comets have collected over the eons.

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

Addendum

South pole ice

The south pole of the Moon where the presence of water ice is detected by the absorption of neutrons by the hydrogen atoms in the ice. Credit NASA/GSFC/SVS/Roscosmos.

 

10/23/2020 – Ephemeris – What is a Near Rectilinear Halo Orbit?

October 23, 2020 Comments off

This is Ephemeris for Friday, October 23rd. Today the Sun will be up for 10 hours and 34 minutes, setting at 6:44, and it will rise tomorrow at 8:10. The Moon, at first quarter today, will set at 12:46 tomorrow morning.

When the astronauts of the Artemis program head for a landing on the Moon is as little as four years from now they will meet their lunar landing craft or Lunar Gateway space station with landing craft docked to it before they descend to the Moon. The orbit of the gateway and/or lander is an odd one. It’s called a near rectilinear halo orbit. And uses the motion and gravitational interaction of the Moon and Earth to create an orbit of the Moon which is nearly face-on to the Earth. The vehicles will never pass behind the Moon. The orbit will pass 1,900 miles (3,000 km) above the Moon’s north pole and out to 43,000 miles (70,000 km) above the south pole. It’s called a halo orbit, because as seen from the Earth it appears to trace a halo around the Moon.

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

Addendum

NASA CAPSTONE pathfinder for gateway orbit

NASA CAPSTONE* pathfinder for gateway orbit is to be launched next year by Rocket Lab to prove out the near rectilinear orbit for the Lunar Gateway. The orbit will always be more or less face on to the Earth, so it and the lunar lander will be always be in contact with the Earth. Credit Advanced Space via Spaceflight Now.

* Yes, CAPSTONE is an acronym: Cislunarˆ Autonomous Positioning System Technology Operations and Navigation Experiment. Aren’t you glad you asked?

ˆ Cislunar: The volume of space between the Earth and Moon’s orbit.

Lunar Gateway NASA

An artist’s rendition of the Lunar Gateway with the Orion spacecraft docked to it. Credit NASA.

For more information

https://spaceflightnow.com/2019/09/26/nasa-to-fly-cubesat-pathfinder-for-gateway-in-unique-lunar-orbit/

https://www.space.com/nasa-capstone-cubesat-moon-gateway.html

 

10/22/2020 – Ephemeris – Tonight the Moon is hanging out with Jupiter and Saturn

October 22, 2020 Comments off

This is Ephemeris for Thursday, October 22nd. Today the Sun will be up for 10 hours and 37 minutes, setting at 6:45, and it will rise tomorrow at 8:09. The Moon, 1 day before first quarter, will set at 11:41 this evening.

The fat crescent Moon and the planets Jupiter and Saturn will make a pretty triangle low in the southwestern sky tonight. Jupiter has been noticeably approaching Saturn the last few years. Their paths will appear to cross for us the evening of December 21st, the first day of winter. I won’t make any bets on it being clear that night, or any night around here in December. On the 21st of December they will be seen low in the southwest in twilight a third of the diameter of the Moon apart, and both be seen together in binoculars or low power telescope. The eye should resolve them, though Jupiter’s brightness compared to Saturn may make that difficult. Jupiter passes Saturn on average every 20 years.

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 triangle

Jupiter, Saturn, and Moon triangle as it will appear in the south at 8 pm in the eastern US. In the western US the Moon will slide closer to Saturn at the same local time. Created using Stellarium.

10/21/2020 – Ephemeris – Let’s look for the naked-eye planets for this week

October 21, 2020 Comments off

This is Bob Moler with Ephemeris for Wednesday, October 21st. Today the Sun will be up for 10 hours and 40 minutes, setting at 6:47, and it will rise tomorrow at 8:08. The Moon, 2 days before first quarter, will set at 10:39 this evening.

Let’s look for the naked-eye planets for this week. Jupiter and Saturn are both low in the south-southwestern sky at 9 pm. Jupiter is the very bright one. Left and a bit above it will be the somewhat dimmer Saturn. They are closing slowly, so they will cross paths on December 21st and be in the same telescope field that evening. Jupiter will set first tonight at 11:28 with Saturn following at midnight. Off in the east-southeast at 9 pm will be Mars. Since the it was closest 15 days ago its distance is slowly increasing to 40.1 million miles (64.6 million km) away. Brilliant Venus will rise at 4:55 am in the east as it retreats slowly toward the Sun. It’s brilliant and looks like a tiny featureless gibbous moon in telescopes.

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

Addendum

Evening planets

The evening planets and the Moon at 9 pm tonight, October 21, 2020. Click on the image to enlarge. Created using Stellarium.

Binocular Moon

The waxing crescent Moon tonight October 21, 2020 as it might appear in binoculars or a low power telescope. Created using Stellarium.

Morning planet - Venus

The morning planet Venus visible at 7 am October 22, 2020 with some of the stars of morning. Click on the image to enlarge. Created using Stellarium.

Telescopic planets

The planets as seen in a telescope (north up) with the same magnification for the night of October 21/22, 2020. Times of the display are: Jupiter and Saturn, 9 pm; Mars, 11 pm; Venus, 7 am. Apparent diameters: Jupiter, 38.01″; Saturn, 16.61″, rings, 38.69″. Mars, 21.57″, and Venus 13.75″. 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 October 21, 2020. The night ends on the left with sunrise on 22nd. Click on the image to enlarge. Created using my LookingUp program.

10/20/2020 – Ephemeris – The Orionid meteor shower reaches peak overnight

October 20, 2020 Comments off

This is Bob Moler with Ephemeris for Tuesday, October 20th. Today the Sun will be up for 10 hours and 43 minutes, setting at 6:48, and it will rise tomorrow at 8:06. The Moon, 3 days before first quarter, will set at 9:44 this evening.

Halley’s Comet is back! (Pronounced Hall-ee’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 following 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 morning twilight begins.

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

Addendum

Orionid radiant

The Orionid meteor shower radiant at 5 a.m. October 21st. 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 be seen all over the sky. However true Orionids can be traced back to the radiant point. Created using Stellarium.

Halley's meteor shower

We get two meteor showers from Halley’s Comet. The Orionids, when Halley’s meteoroids are approaching the inner solar system, and the Eta Aquariids when they’re leaving. Created using my LookingUp program.

10/19/2020 – Ephemeris – This zodiacal constellation seems fishy

October 19, 2020 Comments off

This is Bob Moler with Ephemeris for Monday, October 19th. Today the Sun will be up for 10 hours and 46 minutes, setting at 6:50, and it will rise tomorrow at 8:05. The Moon, 3 days past new, will set at 8:58 this evening.

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 12 constellations of the Zodiac. 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 that is seen in the stars. It is near where the bright red planet Mars currently is. The right or western end of Pisces is the asterism, or informal constellation, of the Circlet. It’s the loop of 5 stars, the rope around the tail of one of the two fish.

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

Addendum

Pisces finder animation

Pisces finder animation showing the Great Square of Pegasus as a way to find it, though this year bright Mars will show where it is. Created using Stellarium and GIMP.

Mars' apparent path for the rest of 2020

Mars’ apparent path for the rest of 2020 stays within Pisces. Mars doesn’t do a loop de loop as the ancients thought when they thought the Earth was motionless. It’s the effect of the Earth passing Mars in their orbits. Mars will stop its westward or retrograde motion around November 13th and resume its normal eastward motion. This view created using Cartes du Ciel (Sky Charts).