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07/31/2020 – Ephemeris – Previewing August skies

July 31, 2020 Leave a comment

This is Bob Moler with Ephemeris for Friday, July 31st. Today the Sun will be up for 14 hours and 40 minutes, setting at 9:09, and it will rise tomorrow at 6:29. The Moon, 3 days before full, will set at 4:04 tomorrow morning.

Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 38 minutes tomorrow to 13 hours 15 minutes on the 31st. The altitude of the Sun at local noon, that is degrees of angle above the horizon will decrease from 63 degrees tomorrow to just over 53 degrees on the 31st. Straits area listeners can subtract one more degree from those angles. Local noon, when the Sun is due south, is about 1:43 p.m. The big event of the month will be in the late evening sky: The Perseid meteor shower will be best seen on the evening of the 11th before the Moon rises at 12:46 am. August is the first of my two favorite months for viewing the wonders of the summer Milky Way.

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

Addendum

August Evening Star Chart

August 2020 Evening Star Chart_2200-081520

Star Chart for August 2020 (10 p.m. EDT August 15, 2020). Click on image to enlarge. Created using my LookingUp program.

The planets and stars are plotted for the 15th at 10 p.m. EDT in the evening and 5 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian, West 75° longitude. (An hour 45 minutes behind our daylight saving time meridian during EDT). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes earlier than the current time.

Note the chart times are for the 15th. For each week before the 15th add ½ hour (28 minutes if you’re picky). For each week after the 15th subtract ½ hour. The planet positions are updated each Wednesday on this blog. For planet positions on dates other than the 15th.

August Morning Star Chart

August Morning Star Chart

Star Chart for August mornings 2020 (5 a.m. EDT August 15, 2020). Click on image to enlarge. Created using my LookingUp program.

For a list of constellation names to go with the abbreviations click here.

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
  • Leaky dipper drips on Leo.
  • Follow the arc of the handle of the Big Dipper to the star Arcturus, and
  • Extend like a spike to Spica.
  • The Summer Triangle is in red.
  • PerR is the radiant of the Perseid meteor shower (Peaks on the 12th)

Twilight Limits, Nautical and Astronomical

      EDT        
  Morning twilight Evening twilight Dark night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2020-08-01 4h31m 5h19m 22h26m 23h14m 4h04m 4h31m 0.93
2020-08-02 4h33m 5h21m 22h24m 23h12m 0.98
2020-08-03 4h35m 5h22m 22h23m 23h10m 1
2020-08-04 4h37m 5h24m 22h21m 23h08m 1
2020-08-05 4h39m 5h25m 22h19m 23h06m 0.97
2020-08-06 4h41m 5h27m 22h18m 23h04m 0.93
2020-08-07 4h43m 5h28m 22h16m 23h01m 23h01m 23h16m 0.87
2020-08-08 4h44m 5h30m 22h14m 22h59m 22h59m 23h36m 0.8
2020-08-09 4h46m 5h31m 22h12m 22h57m 22h57m 23h57m 0.71
2020-08-10 4h48m 5h33m 22h10m 22h55m 22h55m 0.62
2020-08-11 4h50m 5h34m 22h09m 22h53m 22h53m 0h20m 0.52
2020-08-12 4h52m 5h36m 22h07m 22h51m 22h51m 0h46m 0.42
2020-08-13 4h54m 5h37m 22h05m 22h48m 22h48m 1h16m 0.33
2020-08-14 4h56m 5h39m 22h03m 22h46m 22h46m 1h53m 0.23
2020-08-15 4h57m 5h40m 22h01m 22h44m 22h44m 2h39m 0.15
2020-08-16 4h59m 5h42m 21h59m 22h42m 22h42m 3h35m 0.08
2020-08-17 5h01m 5h43m 21h57m 22h39m 22h39m 4h40m 0.03
2020-08-18 5h03m 5h45m 21h55m 22h37m 22h37m 5h03m 0
2020-08-19 5h05m 5h46m 21h53m 22h35m 22h35m 5h05m 0.01
2020-08-20 5h06m 5h48m 21h52m 22h33m 22h33m 5h06m 0.04
2020-08-21 5h08m 5h49m 21h50m 22h30m 22h30m 5h08m 0.1
2020-08-22 5h10m 5h50m 21h48m 22h28m 22h53m 5h10m 0.19
2020-08-23 5h12m 5h52m 21h46m 22h26m 23h20m 5h12m 0.29
2020-08-24 5h13m 5h53m 21h44m 22h24m 23h51m 5h13m 0.41
2020-08-25 5h15m 5h55m 21h42m 22h22m 5h15m 0.53
2020-08-26 5h17m 5h56m 21h40m 22h19m 0h27m 5h17m 0.64
2020-08-27 5h18m 5h58m 21h38m 22h17m 1h09m 5h18m 0.75
2020-08-28 5h20m 5h59m 21h36m 22h15m 1h59m 5h20m 0.83
2020-08-29 5h22m 6h00m 21h34m 22h13m 2h56m 5h22m 0.91
2020-08-30 5h23m 6h02m 21h32m 22h10m 3h58m 5h23m 0.91
2020-08-31 5h25m 6h03m 21h30m 22h08m 5h04m 5h25m 0.96

Twilight calendar was generated using Cartes du Ciel (Sky Charts).

See my blog post: Twilight Zone for the definitions of the different periods of twilight here: https://bobmoler.wordpress.com/2018/09/27/.

NASA Calendar of Planetary Events

    Date     Time    Event
Aug 1  Sa            Venus: 45.2° W
    1  Sa  04:47 am  Moon South Dec.: 24.1° S
    1  Sa  04:14 pm  Mercury-Pollux: 6.7° S
    1  Sa  07:30 pm  Moon-Jupiter: 1.6° N
    2  Su  09:17 am  Moon-Saturn: 2.4° N
    3  Mo  11:59 am  Full Moon
    9  Su  03:57 am  Moon-Mars: 0.8° N
    9  Su  09:51 am  Moon Apogee: 404700 km
   11  Tu  12:45 pm  Last Quarter
   12  We  09:02 am  Perseid Meteor Shower: ZHR = 90
   12  We  08:59 pm  Venus Greatest Elongation: 45.8° W
   14  Fr  03:22 pm  Moon Ascending Node
   15  Sa  09:01 am  Moon-Venus: 4.2° S
   15  Sa  04:40 pm  Moon North Dec.: 24.2° N
   17  Mo  10:47 am  Mercury Superior Solar Conjunction
   18  Tu  10:41 pm  New Moon
   21  Fr  06:59 am  Moon Perigee: 363500 km
   25  Tu  01:58 pm  First Quarter
   27  Th  07:52 am  Moon Descending Node
   28  Fr  10:06 am  Moon South Dec.: 24.2° S
   28  Fr  09:33 pm  Moon-Jupiter: 1.5° N
   29  Sa  12:40 pm  Moon-Saturn: 2.3° N
Sep 1  Tu            Venus: 44.7° W
All event times are given for UTC-4 hr: Eastern Daylight Saving Time.

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html.

If you go to the above site you can print out a list like the above for the entire year or calendar pages for your time zone.

Sun and Moon Rising and Setting Events

LU              Ephemeris of Sky Events for Interlochen/TC
August, 2020    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Sat  1| 06:29a  09:07p  14:38 | 10:23p  05:14a |      Set  05:04a   97%|
+------+-----------------------+----------------+-----------------------+
|Sun  2| 06:30a  09:06p  14:35 | 10:21p  05:15a |      Set  06:09a   99%|
|Mon  3| 06:31a  09:05p  14:33 | 10:19p  05:17a |Full  Rise 09:35p  100%|
|Tue  4| 06:33a  09:03p  14:30 | 10:17p  05:18a |      Rise 10:06p   98%|
|Wed  5| 06:34a  09:02p  14:28 | 10:16p  05:20a |      Rise 10:32p   94%|
|Thu  6| 06:35a  09:01p  14:25 | 10:14p  05:21a |      Rise 10:55p   89%|
|Fri  7| 06:36a  08:59p  14:23 | 10:12p  05:23a |      Rise 11:16p   82%|
|Sat  8| 06:37a  08:58p  14:20 | 10:10p  05:24a |      Rise 11:36p   75%|
+------+-----------------------+----------------+-----------------------+
|Sun  9| 06:38a  08:56p  14:18 | 10:09p  05:26a |      Rise 11:57p   66%|
|Mon 10| 06:39a  08:55p  14:15 | 10:07p  05:27a |      Rise 12:20a   57%|
|Tue 11| 06:41a  08:53p  14:12 | 10:05p  05:29a |L Qtr Rise 12:46a   47%|
|Wed 12| 06:42a  08:52p  14:10 | 10:03p  05:30a |      Rise 01:16a   38%|
|Thu 13| 06:43a  08:50p  14:07 | 10:01p  05:32a |      Rise 01:53a   28%|
|Fri 14| 06:44a  08:49p  14:04 | 09:59p  05:33a |      Rise 02:39a   20%|
|Sat 15| 06:45a  08:47p  14:01 | 09:58p  05:35a |      Rise 03:35a   12%|
+------+-----------------------+----------------+-----------------------+
|Sun 16| 06:46a  08:46p  13:59 | 09:56p  05:36a |      Rise 04:40a    6%|
|Mon 17| 06:48a  08:44p  13:56 | 09:54p  05:38a |      Rise 05:53a    2%|
|Tue 18| 06:49a  08:42p  13:53 | 09:52p  05:39a |New   Set  08:58p    0%|
|Wed 19| 06:50a  08:41p  13:50 | 09:50p  05:40a |      Set  09:30p    1%|
|Thu 20| 06:51a  08:39p  13:47 | 09:48p  05:42a |      Set  09:59p    5%|
|Fri 21| 06:52a  08:37p  13:44 | 09:46p  05:43a |      Set  10:26p   12%|
|Sat 22| 06:54a  08:36p  13:42 | 09:44p  05:45a |      Set  10:52p   20%|
+------+-----------------------+----------------+-----------------------+
|Sun 23| 06:55a  08:34p  13:39 | 09:42p  05:46a |      Set  11:20p   30%|
|Mon 24| 06:56a  08:32p  13:36 | 09:40p  05:48a |      Set  11:51p   42%|
|Tue 25| 06:57a  08:30p  13:33 | 09:38p  05:49a |F Qtr Set  12:26a   53%|
|Wed 26| 06:58a  08:29p  13:30 | 09:36p  05:51a |      Set  01:09a   64%|
|Thu 27| 06:59a  08:27p  13:27 | 09:34p  05:52a |      Set  01:58a   74%|
|Fri 28| 07:01a  08:25p  13:24 | 09:32p  05:53a |      Set  02:56a   83%|
|Sat 29| 07:02a  08:23p  13:21 | 09:30p  05:55a |      Set  03:58a   90%|
+------+-----------------------+----------------+-----------------------+
|Sun 30| 07:03a  08:22p  13:18 | 09:28p  05:56a |      Set  05:04a   95%|
|Mon 31| 07:04a  08:20p  13:15 | 09:26p  05:58a |      Set  06:10a   98%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

07/30/2020 – Ephemeris – This morning is the first opportunity to launch the Perseverance Rover to Mars

July 30, 2020 Comments off

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

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

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).

07/28/2020 – Ephemeris – The Mars Endurance Rover may launch to Mars on Thursday

July 28, 2020 Comments off

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

Artist's concept of the Mars 2020 Rover launch

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

July 27, 2020 Comments off

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

Sky Dome at 2 am tomorrow morning

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

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?

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.