Archive
07/30/2020 – Ephemeris – This morning is the first opportunity to launch the Perseverance Rover to Mars
This is Ephemeris for Thursday, July 30th. Today the Sun will be up for 14 hours and 42 minutes, setting at 9:10, and it will rise tomorrow at 6:28. The Moon, 3 days past first quarter, will set at 3:11 tomorrow morning.
This morning is the scheduled launch of the Mars 2020 Rover named Perseverance. The launch will have or had launched at 7:50 am. Or the whole thing was scrubbed for today. I can’t tell, I recorded this last Sunday night. To hit a spot on Mars less than six miles in diameter after a six and a half month coasting flight is quite a fete. Mars is not only moving in orbit of the Sun, but also rotating. The aeroshell the rover is packed in must hit the Mars atmosphere in the right place, and the right time despite the light time from Mars of 11 minutes, 22 seconds. It will take 6 minutes, 50 seconds for the rover to land after it hits the top of Mars’ atmosphere. So it will have landed one way or another before we get the signal that it hit the atmosphere.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Atlas V with Mars 2020 Rover aboard on launch pad. Click on the image to enlarge. Credit: United Launch Alliance (ULA).
07/29/2020 – Ephemeris – Let’s look at a the naked-eye planets and not so naked-eye comets for this week
This is Bob Moler with Ephemeris for Wednesday, July 29th. Today the Sun will be up for 14 hours and 45 minutes, setting at 9:11, and it will rise tomorrow at 6:27. The Moon, 2 days past first quarter, will set at 2:27 tomorrow morning.
Let’s look at a the naked-eye planets for this week. Jupiter and Saturn are both low in the southeastern sky in the evening. Jupiter is the very bright one. To the left of it will be Saturn. Both planets will be up most of the night with Jupiter setting first at 5:05 am tomorrow morning and Saturn following at 5:44 am. Comet NEOWISE is in the evening sky fading to below naked-eye visibility and also it is hampered by the bright moon. It was a great sight in this bleak year of 2020. The next planet visible will be Mars which will rise at 12:03 am. Its now down to 60.6 million miles (97.5 million km) away, as the Earth slowly overtakes it at the rate of about 3.6 million miles (5.7 million km) a week. Venus will rise at 3:14 am in the east-northeast as our Morning Star. Finally Mercury will rise at 4:59 am.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Evening planets Jupiter and Saturn seen in the southeast at 10 pm, about 45 minutes after sunset July 29, 2020. Click on the image to enlarge. Created using Stellarium.
The gibbous Moon as it might be seen tonight at 10 pm July 29, 2020. Created using Stellarium.
The morning planets as seen at 5:30 am or about an hour before sunrise July 30,2020. Mercury is showing up, rising at 4:56 amClick on the image to enlarge. Created using Stellarium.
The planets as seen in a telescope (north up) with the same magnification tonight and tomorrow July 29/30, 2020. Apparent diameters: Jupiter, 47.26″; Saturn, 18.45″, rings, 42.98″ at 10 pm. Mars, 14.40″, and Venus 27.78″ at 5:30 am. Mars also displays an enlargement showing surface detail. 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 at sunset and sunrise of a single night starting with sunset on the right on July 29, 2020. The night ends on the left with sunrise on the 30th. Click on the image to enlarge. Created using my LookingUp program.
Finder chart for Comets NEOWISE and Lemmon at 11 pm for the week of 07/29/20 to 08/04/20. NEOWISE will be a visible in binoculars. Lemmon will require a telescope. Labels give name, month/day and predicted magnitude. Click on the chart to enlarge. Created using Cartes du Ciel (Sky Charts).
07/28/2020 – Ephemeris – The Mars Endurance Rover may launch to Mars on Thursday
This is Ephemeris for Tuesday, July 28th. Today the Sun will be up for 14 hours and 47 minutes, setting at 9:12, and it will rise tomorrow at 6:26. The Moon, 1 day past first quarter, will set at 1:49 tomorrow morning.
This Thursday at 7:50 am is the first opportunity to launch the Mars 2020 or Perseverance Rover to Mars to arrive on February 18th 2021. The rover will be launched on a United Launch Alliance Atlas 5/Centaur rocket with 4 solid boosters. To send a payload to Mars one must launch within a specific window of time called a launch period. This was originally from July17 to August 11th. Some issues with testing caused a delay to July 30th. The launch period was extended to August 15th. Miss that and it’s a wait of 26 months until Earth and Mars are in the same relative position to try again. The landing area or ellipse is less than 6 miles long on the long axis and partially overlaps an ancient dried river delta that flowed into Jezero crater.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
An artist’s concept of the Mars 2020 Rover launch. The rocket is an Atlas V with 4 solid boosters and a Centaur upper stage. Credit NASA.
07/27/2020 – Ephemeris – Two meteor showers, one near peak, another just starting
This is Ephemeris for Monday, July 27th. Today the Sun will be up for 14 hours and 49 minutes, setting at 9:13, and it will rise tomorrow at 6:25. The Moon, at first quarter today, will set at 1:18 tomorrow morning. | Tonight’s first quarter Moon will hinder the viewing of Comet NEOWISE and the Southern Delta Aquariid meteor shower until after moonset at 1:18 am. The meteor shower radiant will start out low southeastern sky and end up in the south as twilight brightens. It is usually during this meteor shower that the first Perseid meteors show up. The Perseid meteor shower is the most watched meteor shower of the year. It’s great every year except when there’s a bright Moon. This year the Perseids will reach their peak hourly numbers on the morning of August 12th after sunrise, unfortunately. The Moon will interfere after it rises at 12:46 am, which leaves two hours of moonless meteor viewing earlier on the evening of the 11th.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Sky Dome at 2 am tomorrow morning July 28, 2020 at 2 am. DAqr is the approximate location of the Southern Delta Aquariid meteor shower and PerR is the approximate location of the Perseid radiant. Created using my LookingUp program.
Comet NEOWISE in the evening for July 14, 2020 to July 31, 2020. The horizon is for July 14th at 11 p.m. Click on the image to enlarge. Created using Cartes du Ciel (Sky Chart).
07/24/2020 – Ephemeris – Where did Comet NEOWISE come from?
This is Ephemeris for Friday, July 24th. Today the Sun will be up for 14 hours and 56 minutes, setting at 9:17, and it will rise tomorrow at 6:21. The Moon, 3 days before first quarter, will set at 11:58 this evening.
Ephemeris – Over the weekend Comet C/2020 F3 (NEOWISE) will be moving toward the west in the sky as it continues dimming as the Moon gets brighter. This make for a real challenge to spot. So where do comets hang out when they’re not buzzing the Sun? NEOWISE came in from 709 times the Earth’s distance from the Sun. That’s 66 billion miles (106 billion km), and a round trip that takes 6,800 years to complete. That aphelion point is between where the Kuiper belt of dwarf planets like Pluto and Eris hang out and the more distant Oort Cloud of pristine comets. Comets are leftovers from the formation of the solar system, four and a half billion years ago. The cold that far out preserves the volatile ices until a passing star sends them inward.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet NEOWISE finder chart for tonight July 24, 2020 at 11 pm or about an hour and a half after sunset looking northwest under the Big Dipper. The Moon is brightening up the sky and the comet is getting dimmer. Stellarium shows the comet at around 4th magnitude. I admit I fudged the formula in the app for the comet brightness, using the values from Seiichi Yoshida’s website entry for C/2020 F3 (NEOWISE). Created using Stellarium.
Seiichi Yoshida’s Weekly Information about Bright Comets: http://www.aerith.net/comet/weekly/current.html.
07/22/2020 – Ephemeris – Let’s look at a comet and the naked-eye planets for this week
This is Bob Moler with Ephemeris for Wednesday, July 22nd. Today the Sun will be up for 15 hours even, setting at 9:19, and it will rise tomorrow at 6:19. The Moon, 2 days past new, will set at 11:01 this evening.
Let’s look at a comet and the naked-eye planets for this week. Jupiter now rises at before sunset, so does Saturn. Both are now official evening planets. They are both low in the southeast in the evening. Jupiter is the very bright one. To the left of it will be Saturn. Comet C/2020 F3 (NEOWISE) is visible in the evening sky. A good time to start looking would be about 11 pm toward the northwest. The comet be beneath the bowl of the Big Dipper. The comet is fading as it recedes from the Sun. After tonight the waxing Moon will light up the sky and make the comet harder to spot. The next planet up will be Mars which will rise at 12:41 am. Its now down to 64.2 million miles (103.2 million km) away, as the Earth slowly overtakes it at the rate of about 3.7 million miles (6 million km) a week. Venus will rise at 3:22 am in the east-northeast as our Morning Star.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet NEOWISE finder chart for tonight July 22, 2020 at 11 pm or about an hour and a half after sunset. Created using Stellarium.
Saturn and Jupiter planets plus two southern constellations to the right of them at 11 pm tonight July 22, 2020. Just right of Jupiter is Sagittarius that looks more like a teapot than a centaur with a bow and arrow. Further right is Scorpius the scorpion. Click on the image to enlarge. Created using Stellarium.
Planets visible at 5 am tomorrow morning July 23, 2020. Click on the image to enlarge. Created using Stellarium.
The planets as seen in a telescope (north up) with the same magnification tonight and tomorrow July 22/23, 2020. Apparent diameters: Jupiter, 47.52″; Saturn, 18.48″, rings, 43.04″, Mars, 13.60″, and Venus 33.53″. At 11 pm. Mars also displays an enlargement showing surface detail. The ” symbol means seconds of arc (1/3600th of a degree.) Created using Cartes du Ciel (Sky Charts).
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on July 22, 2020. The night ends on the left with sunrise on the 23rd. Click on the image to enlarge. Created using my LookingUp program.
07/21/2020 – Ephemeris – Saturn’s opposition yesterday and Comet NEOWISE update
This is Ephemeris for Tuesday, July 21st. Today the Sun will be up for 15 hours and 2 minutes, setting at 9:20, and it will rise tomorrow at 6:18. The Moon, 1 day past new, will set at 10:26 this evening.
The planet Saturn passed opposition from the Sun yesterday and is its closest to the Earth at 837 million miles (1,348 km). Saturn’s apparent size doesn’t change much in telescopes over the year because its distance only changes plus or minus 10% over the year and week and a half or so of its synodic period, the period between successive oppositions. Closer to the Sun Comet NEOWISE is approaching and is about to pass above the rear paw of the Great Bear Ursa Major below the bowl of the Big Dipper which marks the bear’s hind end. The comet is higher in the sky than it was last week, but it is fading. Moonlight will begin to affect the comet later this week, so binoculars will definitely help in spotting it.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet NEOWISE finder chart for tonight July 21, 2020 at 11 pm or about an hour and a half after sunset. Created using Stellarium.
Photograph of Comet NEOWISE taken Sunday night at midnight July 20, 2020 EDT. The direction of the bright dust tail of the comet leans a bit to the right. The barely visible thin blue ion tail is pointed more directly away from the Sun. The slower escaping dust tail shows the sideways component of the comet’s motion relative to the Sun. Credit Bob Moler. Camera: Canon EOS REBEL T5, f/3.5, 15 seconds, fixed camera (not tracking), ISO 6400, Focal Length 18mm.
Saturn opposition diagram using the JPL Small-Body Database Browser. I tried to align the Z-axis (vertical) with the Earth on the blue orbit and Saturn on the yellow orbit so the Earth is directly between the Sun and Saturn.
07/20/2020 – Ephemeris – Comet NEOWISE tonight and the spacecraft that discovered it
This is Ephemeris for Monday, July 20th. Today the Sun will be up for 15 hours and 4 minutes, setting at 9:21, and it will rise tomorrow at 6:17. The Moon is new today, and won’t be visible.
With the Moon being new today, that means that by the end of the week it will interfere some with spotting Comet NEOWISE. Tonight the comet will be below the lowest star in the bowl of the Big Dipper. Its head should be as bright as the dimmest star of that dipper (the one that joins the handle to the bowl). Where did the comet’s name come from? Back in 2009 NASA launched the Wide-field Infrared Survey Explorer (WISE) spacecraft to survey the infrared sky. It was a telescope built inside a cylinder of solid hydrogen to keep it near absolute zero. In 10 months the hydrogen sublimated away and the project ended. They found that even a warmed up WISE could still find asteroids, so began the Near Earth Object or NEOWISE program.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet NEOWISE Finder for 11 pm tonight July 20, 2020. Created using Stellarium.
07/17/2020 – Ephemeris – Viewing Comet C/2020 F3 (NEOWISE) this weekend
This is Ephemeris for Friday, July 17th. Today the Sun will be up for 15 hours and 9 minutes, setting at 9:23, and it will rise tomorrow at 6:14. The Moon, 3 days before new, will rise at 4:01 tomorrow morning.
With Comet NEOWISE visible low in the northwest around 11 pm, one might wonder just what a comet is. Comets in general scared the crap out of the peoples of Eurasia. Comets gate crashed the perfect order of the cosmos they had thought up and supposedly caused all sorts of mayhem. As far as I’m concerned this comet is the one bright spot so far this year. A comet is mostly nothing. NEOWISE has a solid nucleus which is perhaps 3 miles (5 km) in diameter and a tail of many million of miles (km) long. If that nucleus was rock instead of frozen gasses, water and pebbles one would need a good sized telescope to spot it. Instead the gasses evaporate creating a giant head that rivals Jupiter in size and a tail all considered pretty good vacuum by earthly standards.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
An animation showing the position of Comet NEOWISE at 11 pm (or approximately an hour and a half after sunset if you’re not from Northern Michigan) for Friday, Saturday and Sunday evenings July 17-19, 2020. Created using Stellarium.
Update
Comet NEOWISE from backyard over tall shrubbery 11:18 pm July 16, 2020. I didn’t have time to focus properly which actually accentuates the stars.
07/16/2020 – Ephemeris – Comet NEOWISE’ orbit and path in our skies
This is Ephemeris for Thursday, July 16th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:24, and it will rise tomorrow at 6:13. The Moon, half way from last quarter to new, will rise at 3:20 tomorrow morning.
Comet NEOWISE is now visible in the northwest at about 11:00 pm. It doesn’t fare too well in twilight. The tail will be near vertical but tilted a bit to the right. The comet’s orbit is tilted about 40 degrees to the Earth’s orbital plane and it is traveling opposite the traffic flow of the planets and asteroids of the solar system. It came from the south and is reaching its northern most position before heading back to the south. It is actually circumpolar now, meaning it is far enough north in our sky so it doesn’t set for those of us in the Grand Traverse region for another 6 days. Its low point will be just scraping the northern horizon. It is still visible in the morning in the northeast, but the evening time is now the best time to view it.
The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comet 2020 F3 NEOWISE at 11 pm July 16, 2020, approximately an hour and a half after sunset. Created using Stellarium.
C/2020 F3 (NEOWISE) orbit. Comet position at July 16 at 8 pm EDT: Earth distance 0.765 au, Sun distance 0.479 au. Credit JPL Small-Body Browser
