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Ephemeris: 07/04/2025 – Mars, 49 years ago today
This is Ephemeris for Independence Day, Friday, July 4th. Today the Sun will be up for 15 hours and 28 minutes, setting at 9:31, and it will rise tomorrow at 6:03. The Moon, 2 days past first quarter, will set at 1:56 tomorrow morning.
Forty-nine years ago today the Viking 1 spacecraft was orbiting Mars looking for a spot to land. NASA was hoping they could land it on July 4th, of our national Bicentennial, but they were having trouble trying to find a smooth enough spot to land. NASA eventually thought they found a smooth enough spot. The lander part of the spacecraft touched down on July 20th 1976, the 7th anniversary of the Apollo 11 landing on the Moon. Though the landing was successful, the area was a lot rougher than we would consider a safe spot to land today. Currently, The United States has two Rovers on the surface studying Mars. It’s an achievement a scientifically advanced democracy can do. I wonder if we will keep it intact for the two hundred and fifty year mark, only one year away?
The astronomical event times given in this blog are for the Traverse City/Interlochen area of Michigan (Lat 44.7° N, Long 85.7° W; EDT, UT – 4 hours) unless stated otherwise. Times will be different for other locations.
Addendum
07/04/2023 – Ephemeris – The Bicentennial space mission
This is Bob Moler with Ephemeris for Independence Day, Tuesday, July 4th. Today the Sun will be up for 15 hours and 28 minutes, setting at 9:31, and it will rise tomorrow at 6:03. The Moon, 1 day past full, will rise at 11:14 this evening.
To celebrate our nation’s 200th birthday, NASA attempted to land the Viking 1 lander on the planet Mars on July 4th, 1976. The Viking was a combination orbiter and lander and had a twin spacecraft arriving almost two months later. Viking 1 entered orbit on June 19th and began to survey the prime landing area, that radar from the Earth suggested would be smooth, to land on the day of the Bicentennial. However, images from orbit showed too many obstructions, so another area was surveyed. The mission planners from JPL found a spot and sent the Viking lander down to land on Mars on another historic date, July 20, 1976, the 7th anniversary of the Apollo 11 landing on the Moon.
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
NASA did finally make a historic landing on July 4th,
the Mars Pathfinder mission, with the first rover to operate on Mars, the Sojourner rover, landed on July 4, 1997. It was a microwave sized rover. The mission on the surface lasted 85 days.
12/06/2022 – Ephemeris – The Moon will pass in front of Mars tomorrow night
This is Bob Moler with Ephemeris for Tuesday, December 6th. Today the Sun will be up for 8 hours and 57 minutes, setting at 5:02, and it will rise tomorrow at 8:06. The Moon, 1 day before full, will set at 7:45 tomorrow morning.
Late tomorrow evening we might get to view a really cool event, clouds permitting, when the full moon will cover or in astronomical lingo occult the planet Mars. In the Grand Traverse Region, this will occur for an hour between approximately 10:15 to 11:15 pm. The exact times depend on your location, and can vary by a minute or two over the IPR coverage area. Being a full moon, Mars might be difficult to spot. It may take binoculars to spot it below, left of the Moon by 9:30, and a small telescope when Mars is near the edge of the Moon. The disappearance of Mars will be at the Moon’s 7 o’clock position, and reappearance at the 4 o’clock position.
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
Mars ingress and egress chart and times for Traverse City, MI. The times will vary by a minute or two in the IPR listening area, ingress being earlier to the west and north and later east and south. Egress times will be earlier west and later east of Traverse City. Mars takes about a minute to completely disappear and reappear again because it’s not an unresolvable point like stars.
Occultation of Mars map. The occultation of Mars by the Moon will be visible from within the bounded area. For Traverse City, MI, Mars will disappear around 10:15 pm, December 7, 2022, and reappear around 11:15 pm.
In astronomical events of solar eclipses and occultations YOU are part of the event. No, not you, but your location. Whether you see the event or not or what time the contacts (ingress, egress) happen depends on your location. And will happen for that location whether you are there, or it’s clear, or not.
12/05/2022 – Ephemeris – Mars will hide behind the full Moon Wednesday night
This is Ephemeris for Monday, December 5th. Today the Sun will be up for 8 hours and 58 minutes, setting at 5:02, and it will rise tomorrow at 8:05. The Moon, 2 days before full, will set at 6:36 tomorrow morning.
Late Wednesday night we might get to view a really cool event when the full moon will cover or in astronomical lingo occult the planet Mars. In the Grand Traverse Region, this will occur for an hour between approximately 10:15 to 11:15 pm. The exact times depend on your location, and can vary by several minutes or more. Being a full moon, Mars might be difficult to spot. I’ll have more and hopefully more accurate information tomorrow. When astronomical objects line up like this, it’s called a syzygy. This time it’s a lineup of the Sun, Earth Moon and Mars in nearly a straight line, with both the Moon and Mars in opposition from the Sun on the same night. When the Moon is in opposition, we call it a full moon instead.
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
Mars ingress and egress chart and times for Traverse City, MI. The times will vary by a minute or two in the IPR listening area, ingress being earlier to the west and north and later east and south. Egress times will be earlier west and later east of Traverse City.
World map showing the area that the occultation of Mars will be visible. Occultation visibility will move from west to east. Credit: Occult version 4.
11/22/2022 – Ephemeris – Finding Taurus the bull
This is Ephemeris for Tuesday, November 22nd. Today the Sun will be up for 9 hours and 19 minutes, setting at 5:08, and it will rise tomorrow at 7:50. The Moon, 1 day before new, will rise at 7:30 tomorrow morning.
Low in the east at 8 this evening and below the beautiful Pleiades star cluster is Taurus the bull. His face is a letter V shape of stars lying on its side, the star cluster Hyades, with the bright orange-red star Aldebaran at one tip of the V as its angry blood-shot eye, but actually about halfway between us and the cluster. The Pleiades star cluster is in his shoulder. Taurus is seen charging downward at that hour, the soon to rise constellation of Orion, with bright Mars near the horn tips. Taurus in Greek mythology was the form the god Zeus assumed when he carried off the maiden Europa. Europa’s still with him as the intriguing satellite completely covered by an ocean below its icy exterior, and orbiting Zeus’ Roman equivalent, the planet Jupiter.
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
Taurus, Pleiades and Mars finder animation for 8:30 pm tonight, November 22, 2022. Mars is the interloper this year, seen between the horns of Taurus the Bull. The V of stars that make up the face of Taurus the bull is a star cluster of stars called the Hyades. In Greek mythology, they are the half-sisters of the Pleiades. Created using Stellarium, LibreOffice Draw, and GIMP.
Mars retrograde path from October 29, 2022, to January 11, 2023, against the stars of Taurus the bull. It will be at opposition on December 7, and actually closest to the Earth on November 30 at 50.61 million miles or 81.45 million kilometers. In the upper right is the beautiful Pleiades star cluster, also known as the Seven Sisters. Below and right is the V shaped star cluster that represents the face of Taurus the bull, with the bright red star Aldebaran as the bull’s angry red eye. That V of stars is called the Hyades, who in mythology were the half sisters to the Pleiades. Created using Cartes du Ciel (Sky Charts) and GIMP.
The Rape of Europa by Titian. According to the story, Zeus as a bull abducted Europa and swam to Crete, where she became the first queen of that island, and bore him three sons. Other paintings of this subject are by Rembrandt and de Troy. This painting belongs to the Isabella Stewart Gardener Museum in Boston, MA.
10/04/2021 – Ephemeris – Why we can’t talk to the Perseverance rover on Mars right now
This is Ephemeris for Monday, October 4th. Today the Sun will be up for 11 hours and 32 minutes, setting at 7:17, and it will rise tomorrow at 7:46. The Moon, 2 days before new, will rise at 6:30 tomorrow morning.
NASA is no longer sending commands to its Perseverance rover or any of its assets roving or orbiting Mars now. The reason isn’t particularly sinister. It’s the approximately 26 month Mars solar conjunction. The Sun is a noisy radio source, and commands sent to or data received from these martian assets could be garbled. This affects everyone’s assets on or orbiting Mars, which includes the Europeans, India, China and the United Arab Emirates. For NASA, communication restrictions started two days ago and will last until the 14th. This will give the folks at JPL who are operating the Curiosity and Perseverance rovers some time off, and time to plan the next few months of activity.
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
Mars in solar conjunction. Looking at the inner solar system. Mars, near the bottom of the image, is 244.6 million miles (393.9 million kilometers) from Earth. Click on the image to enlarge it. Credit NASA’s Eyes app.
Mars beyond and to the upper left of the Sun yesterday. It’s tough to get intelligible radio signals through the solar corona. Credit: NASA/ESA SOHO* spacecraft. The annotation is mine.
* SOlar and Heliospheric Observatory, spacecraft in halo orbit around the Lagrangian L1 equilibrium point about 930,000 miles (1,500,000 kilometers) sunward of the Earth. This keeps the satellite roughly between the Sun and the Earth, instead of moving ahead of the Earth because it’s closer to the Sun.
06/22/2021 – Ephemeris – Mars is poised to cross in front of the Beehive Star Cluster tonight
This is Bob Moler with Ephemeris for Tuesday, June 22nd. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32, and it will rise tomorrow at 5:57. The Moon, 2 days before full, will set at 4:41 tomorrow morning.
Tonight, the planet Mars will be at the western edge of the Beehive star cluster. Tomorrow night, Mars will be seen against its stars. Normally, the Beehive star cluster is easily seen in binoculars. The problem is, that both the cluster and Mars will be low in the west-northwestern sky, only six to seven degrees above a sea or lake horizon near the optimal time to spot them of 11 pm. It has been 8 months since Mars was opposite the Sun in our skies, and relatively close to us. Back then it was as bright as Jupiter and relatively close to the Earth. Now, Mars is 221 million miles (356 million kilometers) and 5 times farther aw0ay, about half the distance to Jupiter. It’s tiny in telescopes and very hard to pick out of the dim twilight glow of 11 pm.
The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT-4). They may be different for your location.
Addendum
Mars passing in front of M44 as a GIF animation. This is difficult to spot with binoculars low in the west-northwest at 11 pm on the nights of June 22nd, 23rd and 24th. The Beehive star cluster is a relatively close and sparse cluster. On dark nights in early spring, the cluster looks like a fuzzy spot to the naked-eye. It reveals its true nature in binoculars. Created using Cartes du Ciel.
02/23/2021 – Ephemeris – The Perseverance rover landed on Mars taking video all the way down
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
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.
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.
02/18/2021 – Ephemeris – The Perseverance Rover will land on Mars this afternoon
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
Graphic of the Entry, Descent and Landing of the Perseverance Rover. Click on the image to enlarge. Credit: NASA/JPL.
Perseverance drilling for a sample in Jezero crater. Artist drawing – NASA/JPL
02/16/2021 – Ephemeris – Perseverance lands on Mars in two days
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
Graphic of the Entry, Descent and Landing (EDL) of the Perseverance Rover. Click on the image to enlarge. Credit: NASA/JPL.
Bob Moler's Ephemeris Blog 