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Archive for the ‘Ephemeris Program’ Category

02/26/2021 – Ephemeris – Origin of the Moon

February 26, 2021 Leave a comment

This is Ephemeris for Friday, February 26th. Today the Sun will be up for 11 hours and 1 minute, setting at 6:26, and it will rise tomorrow at 7:23. The Moon, 1 day before full, will set at 7:59 tomorrow morning.

The origin of the Moon is a question that has vexed astronomers for years. Did it break off the molten Earth like a cell dividing? Was it captured by passing too close to the Earth? Neither is satisfactory. Chemical elements have different isotopes depending on the number of neutrons in their nucleus. The rocks brought back by the Apollo astronauts show that the isotopes of the elements in the rocks are the same as for the Earth. We know that Mars and the asteroids have different isotope ratios. The hypothesis that seems most likely is that another planet, the size of Mars collided with the 100 million-year-old Earth in a glancing blow that gave rise to a disk of material that eventually coalesced to form the Moon.

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

Addendum

How the Moon may have formed

A progression of how the Moon may have formed by a small protoplanet crashed into the Earth. Credit: Brian Koberlein.

02/25/2021 – Ephemeris – Moon Dust, bad stuff

February 25, 2021 Leave a comment

This is Ephemeris for Thursday, February 25th. Today the Sun will be up for 10 hours and 58 minutes, setting at 6:25, and it will rise tomorrow at 7:24. The Moon, 2 days before full, will set at 7:30 tomorrow morning.

One of the big problems that will have to be solved before the Artemis program sets up a permanent base on the Moon is what to do about lunar soil or Moon dust. That stuff gets into everything. The Apollo astronauts said it smelled like gunpowder. Unlike beach sand the particles aren’t rounded, but angular, being produced by rocks being hit by meteoroids large and micro over the eons by space weathering. With no atmosphere small particles can even weld themselves together. Though no studies have been done, any brought into the habitat would do damage to the lungs, like that to miners on Earth. Moon dust has compromised the seals on the containers of soil the Apollo crews brought back from the Moon.

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

Addendum

Lunar soil

Lunar soil sample. Credit Larry Taylor U of TN Knoxville from https://ntrs.nasa.gov/api/citations/20090026015/downloads/20090026015.pdf

02/24/2021 – Ephemeris – Let’s search for the naked-eye planets for this week

February 24, 2021 Leave a comment

This is Bob Moler with Ephemeris for Wednesday, February 24th. Today the Sun will be up for 10 hours and 55 minutes, setting at 6:24, and it will rise tomorrow at 7:26. The Moon, 3 days before full, will set at 6:56 tomorrow morning.

Let’s search for the naked-eye planets for this week. Unfortunately the only one you’ll find is Mars. The other four are hanging out in the direction of the Sun and won’t be seen for a week or two. They’ll be first seen low in the morning sky. Mars can be found high in the west-southwest and below the Pleiades at 8 pm tonight. Mars is moving rapidly eastward. It just entered the constellation of Taurus the bull, which is a lot wider than Aries, astronomically*, and will set at 1:26 am. Of the outer planets Mars is the fastest, being the nearest to the Sun, and to the Earth, so unlike Jupiter, Saturn and the stars which rise and set about four minutes earlier each night, Mars sets about a minute earlier each night now.

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

* Astrologically the all the constellations or signs of the zodiac are 30 degrees wide. According to the International Astronomical Union (IAU) Aries is 25 degrees wide along the ecliptic, while Taurus is 37 degrees wide as measured using the Stellarium planetarium program. I do astronomy on Ephemeris, and consider astrology astronomy’s illegitimate parent.

Addendum

Mars finder animation

Mars finder animation with 3 layers: Unannotated chart, Labels and constellation lines added, and boundaries added. Created using Stellarium and GIMP.

The gibbous Moon as it might be seen in binoculars this evening at 8 pm tonight, February 24, 2021. Created using Stellarium.

Planets and the Moon on a single night sunset 02/24/21 to sunrise 02/25/21

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on February 24, 2021. The night ends on the left with sunrise on the 25th. There is a planet traffic jam in the morning and the labels for Jupiter and Mercury overlap. Unfortunately these planets rise too soon before the Sun to be seen for us up north. It is a great sight for Southern Hemisphere observers. Click on the image to enlarge. Created using my LookingUp program.

Categories: Ephemeris Program, Planets Tags: ,

02/23/2021 – Ephemeris – The Perseverance rover landed on Mars taking video all the way down

February 23, 2021 Leave a comment

Note: There was a news conference at JPL, Monday at 2 pm EST where videos of the parts of the landing were shown. Most hadn’t made it to the https://mars.nasa.gov website by Monday night. The news conference with the videos can be found on NASA TV, NASA’s YouTube channel and other sites.

This is Ephemeris for Tuesday, February 23rd. Today the Sun will be up for 10 hours and 52 minutes, setting at 6:22, and it will rise tomorrow at 7:28. The Moon, halfway from first quarter to full, will set at 6:15 tomorrow morning.

It looks like the Perseverance Rover was gently lowered to a flat spot in Jezero crater on Mars about a kilometer or two from the edge of the river delta it was aiming to be near. It is in the midst of checkouts and the unfolding of its masts and its various appendages. For the third time the Mars Reconnaissance Orbiter was able to take a picture of the entry craft on its parachute seen above the delta, as it had with Curiosity and the Phoenix lander before all the while performing its communication relay duties. A few images have come back from Percy, as the Rover is nicknamed as I record this Sunday night. By Monday Percy should have sent back more images and perhaps parts of the landing video.

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

Addendum

Looking down at Perseverance from the Sky Crane

A frame from the video looking down at the Perseverance rover from the Sky Crane. In the video as the rover neared the ground it was enveloped by a cloud of dust, so the support lines simply disappeared into the cloud of dust that enveloped the rover. Click on the image to enlarge. Credit NASA/JPL.

Perseverance rover on the parachute from MRO

The Perseverance rover on the parachute over Jezero crater from the Mars Reconnaissance Orbiter. The circle on the image is the point where the rover landed. Click on the image to enlarge. Credit NASA/JPL-Caltech/University of Arizona.

02/19/2021 – Ephemeris – Let’s look at the first quarter Moon tonight

February 19, 2021 Comments off

This is Ephemeris for Friday, February 19th. Today the Sun will be up for 10 hours and 40 minutes, setting at 6:17, and it will rise tomorrow at 7:34. The Moon, at first quarter today, will set at 2:32 tomorrow morning.

I love a first quarter Moon. The terminator or sunrise line cuts the Moon in half. Lots of craters are easily seen due to the long shadows cast by their crater walls. Best seen in a small telescope or strong pair of binoculars is a three crater chain just below left of the center of the Moon. The top and largest crater is Ptolemaeus. Below and connected to it is Alphonsus. A bit below Alphonsus is Arzachel. Alphonsus is the interesting one. In the pre-Apollo days amateur and some professional astronomers saw glows or mists in Alphonsus. In 1958 a Russian astronomer obtained spectra of one such mist. In 1965 the last Ranger mission to impact the Moon was sent to Alphonsus, but it didn’t find anything unusual.

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

Addendum

The first quarter Moon tonight at 8 pm, February 19, 2021, as it might be seen in binoculars. Created using Stellarium.

First Quarter Moon

A telescopic like view of the Moon via the Virtual Moon Atlas pointing out the craters discussed in the text.

Ranger image 1

Ranger 9 Image of Alphonsus #1. Credit NASA/JPL.

Ranger Program

Left: The Ranger spacecraft. Right: The floor of the crater Alphonsus form Ranger 9. Only the last 3 spacecraft were successful. They transmitted images all the way down as they crashed into the Moon. Credit NASA/JPL.

02/18/2021 – Ephemeris – The Perseverance Rover will land on Mars this afternoon

February 18, 2021 Comments off

This is Ephemeris for Thursday, February 18th. Today the Sun will be up for 10 hours and 37 minutes, setting at 6:15, and it will rise tomorrow at 7:36. The Moon, 1 day before first quarter, will set at 1:30 tomorrow morning.

Later this afternoon the Perseverance Rover will land in Jezero crater on Mars. NASA will have a live Internet feed from the Jet Propulsion Laboratory starting at 2:15 pm EST (19:15 UTC). Atmospheric entry will be at 3:48 pm EST (20:48 UTC), landing at 3:55 pm EST (20:55 UTC). This is Earth received time. The events actually happened 11 minutes 22 seconds earlier on Mars. Though cameras on the spacecraft will be recording the landing activity it will not be sent to Earth in real time due to the weak signal during entry. The spacecraft will be sending tones only for specific events during what is called EDL, Entry, Descent and Landing or “Seven Minutes of Terror”. If all goes well the first images will be taken and sent of its surroundings. And in the next weeks we’ll get an actual replay sent back of the landing with color and sound. It will be so cool!

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

Addendum

Links

NASA on YouTube: https://www.youtube.com/results?search_query=nasa

NASA TV: https://www.nasa.gov/multimedia/nasatv/#public

Entry, Descent and Landing

Graphic of the Entry, Descent and Landing of the Perseverance Rover. Click on the image to enlarge. Credit: NASA/JPL.

Perseverance drilling for sample

Perseverance drilling for a sample in Jezero crater. Artist drawing – NASA/JPL

02/17/2021 – Ephemeris – Let’s search for the naked-eye planets for this week

February 17, 2021 Comments off

This is Bob Moler with Ephemeris for Ash Wednesday, Wednesday, February 17th. Today the Sun will be up for 10 hours and 34 minutes, setting at 6:14, and it will rise tomorrow at 7:38. The Moon, 2 days before first quarter, will set at 12:27 tomorrow morning.

Let’s search for the naked-eye planets for this week. Unfortunately the only one you’ll find is Mars. The other four are hanging out in the direction of the Sun and won’t be seen until spring. They’ll be first seen in the morning sky. Mars can be found high in the southwest and above the waxing crescent Moon at 8 pm tonight. They will be even closer Thursday night. Mars is increasing its speed eastward through the constellation of Aries the ram, which it’s two thirds the way through, and will set at 1:32 am. Of the outer planets Mars is the fastest, being the nearest to the Sun, and the Earth, so unlike Jupiter, Saturn and the stars which rise and set about four minutes earlier each night, Mars sets less than a minute earlier each night now.

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

Addendum

Mars and the Moon finder chart

Mars and the Moon in the southwestern sky at 8 pm tonight, February 17, 2021. Created using Stellarium.

Binocular Moon

The Moon as it might appear tonight at 8 pm, February 17, 2021. Created using Stellarium.

Planets and the Moon on a single night sunset 02/17/21 to sunrise 02/18/21

Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on February 17, 2021. The night ends on the left with sunrise on the 18th. There is a planet traffic jam in the morning and the labels for Jupiter and Mercury overlap. Unfortunately these planets rise too soon before the Sun to be seen for us up north. It is a great sight for Southern Hemisphere observers. Click on the image to enlarge. Created using my LookingUp program.

Categories: Ephemeris Program, Planets Tags: ,

02/16/2021 – Ephemeris – Perseverance lands on Mars in two days

February 16, 2021 Comments off

This is Ephemeris for Fat Tuesday, Tuesday, February 16th. Today the Sun will be up for 10 hours and 32 minutes, setting at 6:13, and it will rise tomorrow at 7:39. The Moon, 3 days before first quarter, will set at 11:24 this evening.

In two days, Thursday afternoon, the Perseverance Rover will land on the planet Mars in a crater call Jezero. It’s mission to actually look for evidence of past life, fill specimen tubes to be cached for later pickup and returned to earth by a future mission, presumably by the end of the decade. It is also bringing a helicopter drone named Ingenuity to check out the feasibility of using future aircraft in Mars rarefied atmosphere. The vehicle, including the back shell and descent stage sports 23 cameras. Even Ingenuity has 2 cameras. That shouldn’t be a big deal today. Heck, my smartphone has 5 cameras, each with lots more megapixels than the digital camera I bought 15 years ago. Only two days to go to landing.

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

Addendum

Entry, Descent and Landing

Graphic of the Entry, Descent and Landing (EDL) of the Perseverance Rover. Click on the image to enlarge. Credit: NASA/JPL.

Link to the Mars 2020 Perseverance Landing Press Kit

02/12/2021 – Ephemeris – Monoceros the unicorn

February 12, 2021 Comments off

This is Ephemeris for Darwin Day, Friday, February 12th. Today the Sun will be up for 10 hours and 20 minutes, setting at 6:07, and it will rise tomorrow at 7:45. The Moon, 1 day past new, will set at 7:07 this evening.

Among all the constellations in the sky of animals real and mythical, there is also a unicorn. It’s called Monoceros, and inhabits the southeastern sky at 8 p.m. mostly bounded by Orion on the right, Canis Major, the great dog below and Canis Minor, the little dog to the left and above. Unfortunately for observers without a telescope Monoceros, is devoid of any but the faintest stars. Maybe that’s why no one sees unicorns anymore. It has many faint stars because the Milky Way runs through it. To the telescope it is a feast of faint nebulae or clouds of gas and dust, the birthplace of stars, including the red rose of the Rosette Nebula, and Hagrid’s Dragon Cluster (NGC 2301). It also contains a beautiful telescopic triple star system, Beta (β) Monocerotis.

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

Addendum

Monoceros finder chart

Monoceros finder chart showing neighboring constellations for about 8 pm in mid-February. Created using Stellarium.

The brighter stars of NGC 2301 (Hagrid’s Dragon Cluster, AKA Great Bird Cluster and Copeland’s Golden Worm). It’s also in two other catalogs: Cr 119 and Mel 54. Created using Stellarium and GIMP. Dragon from “Dragon Flying Cycle” on YouTube by Simon Hussey.

Deep Sky Objects around Monoceros

Deep Sky Objects in and around Monoceros. Click on the image to enlarge. Created using Stellarium.

Rosette Nebula

Rosette Nebula in the infrared from the Spitzer Space Telescope. The star cluster in the center is visible in a telescope, but the nebula is strictly photographic. Credit: NASA/JPL/Caltech.

Beta Monocerotis

Telescopic Beta Monocerotis. William Hershel, discoverer of Uranus, said that it was “One of the most beautiful sights in the heavens.” Credit: F. Ringwald, Fresno State.

02/11/2021 – Ephemeris – The Winter Triangle

February 11, 2021 Comments off

This is Ephemeris for Thursday, February 11th. Today the Sun will be up for 10 hours and 17 minutes, setting at 6:06, and it will rise tomorrow at 7:47. The Moon is new today, and won’t be visible.

I usually talk about the Winter Circle of bright stars, but some other astronomers talk about the Winter Triangle. The stars involved are Betelgeuse in the hunter Orion, Sirius in Canis Major, Orion’s large hunting dog, and Procyon in Canis Minor, his other small hunting dog. These three stars enclose a rather blank piece of sky with the faint Milky Way running through it and the almost invisible constellation of Monoceros the unicorn. The Summer Triangle has three bright stars with no other close competition. The Winter Triangle has four other bright stars near it. Any three of these would make a nice triangle. One of these constellations Canis Minor is tiny, with Procyon and one other star. It makes me think of a dachshund, or maybe, if I’m hungry, a hot dog.

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

Addendum

Winter triangle finder animation

Winter Triangle finder animation. It shows the star field, named first magnitude stars, then their constellations, then the Winter Triangle and constellations of the three stars. Click on the image to enlarge. Created using Stellarium and GIMP.