Archive

Archive for the ‘Comet’ Category

07/29/2020 – Ephemeris – Let’s look at a the naked-eye planets and not so naked-eye comets for this week

July 29, 2020 Comments off

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

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.

Binocular Moon

The gibbous Moon as it might be seen tonight at 10 pm July 29, 2020. Created using Stellarium.

Morning planets

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.

Planets and the Moon on a single night

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 on a single night

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.

Comets NEOWISE and Lemmon at 11 pm for the week

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).

07/24/2020 – Ephemeris – Where did Comet NEOWISE come from?

July 24, 2020 Comments off

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

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.

07/23/2020 – Ephemeris – The two tails of Comet NEOWISE

July 23, 2020 Comments off

This is Bob Moler with Ephemeris for Thursday, July 23rd. Today the Sun will be up for 14 hours and 58 minutes, setting at 9:18, and it will rise tomorrow at 6:20. The Moon, 3 days past new, will set at 11:31 this evening.

Tonight Comet C/2020 F3 (NEOWISE) has moved so it is not below the bowl of the Big Dipper but more below the handle. It is dimming, so it is best found with optical aid like a pair of binoculars. Many pictures of it can be found now on the Internet and in print. Many photos show that the comet has two distinct tails. A broad whitish tail that we can see visually and a thin blue one separated by a slight angle. To the eye we see the broad tail which is made of dust. The particles are pushed away from the Sun by the force of sunlight itself. The blue tail is made of ionized gasses and pushed back by the solar wind. This tail leaves the comet’s head faster than the dust so the comet’s sideways motion to the Sun causes the tails to separate. The tail on the chart below closely matches the direction of the ion tail. The brighter dust tail is canted to the right.

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

Comet NEOWISE finder chart for tonight July 23, 2020 at 11 pm or about an hour and a half after sunset looking northwest under the Big Dipper. Created using Stellarium.

07/22/2020 – Ephemeris – Let’s look at a comet and the naked-eye planets for this week

July 22, 2020 Comments off

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

Comet NEOWISE finder chart for tonight July 22, 2020 at 11 pm or about an hour and a half after sunset. Created using Stellarium.

Evening planets & southern constellations

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 seen in the morning

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 on a single night

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

July 21, 2020 Comments off

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

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

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

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

July 20, 2020 Comments off

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

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

July 17, 2020 Comments off

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

Comet NEOWISE 7/17 to 7/19/2020

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

NEOWISE from backyard over tall shrubery

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

July 16, 2020 Comments off

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

NEOWISE evening_2300-071620

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

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

07/14/2020 – Ephemeris – Comet NEOWISE is now visible in the evening sky

July 14, 2020 Comments off

This is Ephemeris for Tuesday, July 14th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:25, and it will rise tomorrow at 6:11. The Moon, 2 days past last quarter, will rise at 2:19 tomorrow morning.

Comet C/2020 F3 also known as NEOWISE a NASA acronym was discovered in late March by the Wide-Field Infrared Survey Explorer or WISE spacecraft on its add-on mission. It was looking for Near Earth Objects or NEOs, hence the name NEOWISE. The comet passed its closest to the Sun on July 3rd and is now outbound on its nearly 7,000 year orbit. It’s now visible in the evening sky seen generally below the Big Dipper in the northwestern sky but much closer to the horizon as soon as it gets sufficiently dark. Binoculars will help you locate the comet which should be of naked-eye brightness for the rest of the month, though it will be fading all the way, though it now appears brighter than predicted. Also photographs make the comet appear brighter than it is to the eye.

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

Addendum

NEOWISE in the morning

My photograph of Comet NEOWISE at 4:40 am Sunday morning July 12, 2020 over the west arm of Grand Traverse Bay south of the Discovery Pier off M22. (For non-Michigander astronomers M22 is not the globular star cluster in Sagittarius, but a very scenic Michigan state road.) Click on the image to enlarge.

Comet NEOWISE in the evening for July 14, 2020 to July 31, 2020

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).

 

07/07/2020 – Ephemeris – New Comet NEOWISE (C/2020 F3) is visible in the morning

July 7, 2020 Comments off

This is Ephemeris for Tuesday, July 7th. Today the Sun will be up for 15 hours and 24 minutes, setting at 9:29, and it will rise tomorrow at 6:06. The Moon, 2 days past full, will rise at 11:37 this evening.

Comet C/2020 F3 (NEOWISE) is visible in the morning now, and quite bright. At 5 am in twilight it will be very low in the northeast tomorrow morning, below the bright star Capella. I’ve seen a photograph of it showing a tail. Over the next week it will be moving northward along the horizon at 5 am and fading as it goes. Then it will become visible in the evening sky next week. It is best seen in binoculars, though it can be spotted with the naked eye. One needs a low northeastern horizon. That’s the problem with comets: they’re brightest when close to the Sun, and can be seen best only when the Sun isn’t up. So that leaves morning or evening twilight, unless they are a huge comet like Hale-Bopp of 23 years ago that doesn’t get close to the Sun.

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

Addendum

Comet NEOWISE in the morning

Comet NEOWISE starting at 5 am February 8, 2020. Every second date has month-day and predicted magnitude. The sky will be a bit higher each morning. Created using Cartes du Ciel (Sky Charts)