06/06/2022 – Ephemeris – In June we spend our evenings in the twilight zone

This is Ephemeris for Monday, June 6th. Today the Sun will be up for 15 hours and 27 minutes, setting at 9:25, and it will rise tomorrow at 5:57. The Moon, 1 day before first quarter, will set at 2:28 tomorrow morning

We spend our evenings after sunset during the months of June and July, pretty much in the twilight zone. Actually, it’s just twilight. There are three twilight periods: Civil, Nautical and Astronomical. In the evening, civil twilight lasts from sunset to when the Sun drops to 6 degrees below the horizon. The scene around is still quite bright, but car headlights still need to be on. Nautical twilight lasts until the Sun is 12 degrees below the horizon. Bright stars and the horizon are visible for sextant use. After that is astronomical twilight until the Sun is 18 degrees below the horizon, when the stars become more and more numerous. After that it’s officially dark, Moon permitting. This time of year we’re lucky to get three and a half hours of darkness.

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

Daylight, twilight, and dark example for June 6, 2022. This graph is centered on midnight. Light blue is daylight, while the three darker shades of blue denote the three twilight periods of civil, nautical and astronomical. The yellow lines show when the Sun, Moon and planets are visible. Dark of night is relegated only to the morning hours, thanks to the season, daylight saving time and our location 43 minutes west of our standard time meridian. The chart is produced by the app Cartes du Ciel (Sky Charts).

01/04/2022 – Ephemeris – Planet show in the evening twilight tonight

This is Bob Moler with Ephemeris for Tuesday, January 4th. The Sun will rise at 8:20. It’ll be up for 8 hours and 55 minutes, setting at 5:15. The Moon, 2 days past new, will set at 7:34 this evening.

Tonight, if it’s clear, there’s a chance that one could spot four planets, plus the Moon, in the southwestern evening twilight. However, not all at the same time. Venus should make an appearance at about 5:45 very low in the west-southwest, only 3 degrees or 6 moon-widths above a lake horizon. Jupiter might be visible then or in a few more minutes much higher in the southwest. The two-day-old Moon might be visible then, about halfway between Jupiter and Venus. By 6 pm, Mercury might be visible halfway between the Moon and where Venus was, because Venus will be setting at that time. By this time, too, Saturn will appear just above right of the Moon. This is the last chance to spot Venus in the evening sky until the last months of this year.

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

Four Evening planets and the Moon at 5:45 pm on a flat horizon at 5:45 pm tonight, January 4, 2022. Venus, because it is so low on the horizon, and Saturn, the dimmest of the four planets, may not be visible. Created using Stellarium.

Venus is only 4 days away from inferior conjunction. Back in 1969 I took this photo of Venus then only 4 days from inferior conjunction from the Grand Rapids Amateur Astronomical Society’s Veen Observatory outside of Lowell, MI.

Venus was low in the sky, and the atmosphere made it very fuzzy.

09/27/2018 – Ephemeris – Twilight zone

Ephemeris for Thursday, September 27th. The Sun will rise at 7:35. It’ll be up for 11 hours and 54 minutes, setting at 7:30. The Moon, 3 days past full, will rise at 9:12 this evening.

It will get dark tonight with the end of astronomical twilight at 9:11 p.m., and a minute later the bright Moon will rise spoiling the dark sky. Speaking of astronomical twilight there are three twilight periods: Civil, Nautical and Astronomical. In the evening civil twilight lasts from sunset to when the Sun drops to 6 degrees below the horizon. The scene around is still quite bright, but car headlights still need to be on. Nautical twilight lasts until the Sun is 12 degrees below the horizon. Bright stars and the horizon are visible for sextant use. After that is astronomical twilight until the Sun is 18 degrees below the horizon, when the stars become more and more numerous. After that it’s officially dark, Moon willing.

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

Addendum

Twilight phases

More information about twilight, dusk and dawn can be found here:  https://www.timeanddate.com/astronomy/different-types-twilight.html.

04/06/2018 – Ephemeris – Marking the passage of 13 hours of daylight

Ephemeris for Friday, April 6th. The Sun will rise at 7:14. It’ll be up for 13 hours and 2 minutes, setting at 8:16. The Moon, 2 days before last quarter, will rise at 2:33 tomorrow morning.

Tomorrow morning early, the crescent Moon will pass Saturn and Mars. These planets will be below the Moon in the dark early morning hours. The dark night hours will be increasingly more inaccessible as summer approaches. Today we’ve broached 13 hours of daylight. By the summer solstice on June 21st the Sun will be out just a bit over 15 and a half hours. Meaning that the Sun will be down for only eight and a half hours, with only three and a half hours of really dark sky, Moon permitting, between the end of evening astronomical twilight and the beginning of morning astronomical twilight. Twilight is really long around the summer solstice because the Sun sets at a shallow angle.

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

Addendum

Definitions

End or start of Civil Twilight:  Sun is 6° below the horizon

Brighter planets become visible

End or start of Nautical Twilight:  Sun is 12° below the horizon

Brighter deep sky objects can be found for public star parties

End or start of astronomical twilight:  Sun is 18° below the horizon

On moonless nights, the twilight glow is gone and the sky is dark

02/01/2018 – Ephemeris – Previewing February skies

Ephemeris for Thursday, February 1st. The Sun will rise at 8:01. It’ll be up for 9 hours and 49 minutes, setting at 5:51. The Moon, 1 day past full, will rise at 7:30 this evening.

Lets look ahead at our short month of February. It’s so short that this year it has no full moons. To make up for it both January and March have two. We’re in the depths of winter but the Sun is continuing its return to northern climes. This is reflected in the increase in daylight hours, from 9 hours 49 minutes today to 11 hours 7 minutes on the 28th. These times are for the Interlochen/Traverse City area. Daylight durations are slightly shorter in the northern part of our listening area and slightly longer to the south. As the month goes on the weather should generally warm and clear up. Venus is moving away from the Sun and will become more and more visible after sunset as the month wears on. Today Venus will set 24 minutes after the Sun. This will increase to an hour after the Sun.

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

Addenda

February Evening Sky Chart

Star Chart for February 2018 (9 p.m. EST February 15, 2018). Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 9 p.m. EST in the evening and 6 a.m. for the morning chart. These are the chart times. Note that Traverse City is located approximately 45 minutes behind our time meridian. (An hour 45 minutes behind our daylight saving time meridian. during EDT and 45 minutes behind our daylight standard time meridian. during EST). To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes (Daylight Time) or 45 minutes (Standard Time) earlier than the current time if you are near your time meridian.

Note the chart times of 9 p.m. and 6 a.m. are for the 15th. For each week before the 15th add ½ hour. 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, check the Wednesday planet posts on this blog.

February Morning Star Chart

Star Chart for February 2018 mornings based on 6 a.m. February 15th. Created using my LookingUp program. Click on image to enlarge.

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

Star chart annotations

• Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
• Leaky Big Dipper drips on Leo.
• Follow the arc of the handle of the Big Dipper to the star Arcturus.
• The Summer Triangle is in red.

Twilight

Evening nautical twilight ends at 6:58 p.m. EST on the 1st, increasing to 7:31 p.m. EST on the 28th.
Evening astronomical twilight ends at 7:30 p.m. EST on the 1st, increasing to 8:04 p.m. EST on the 28th.
Morning astronomical twilight starts at 6:22 a.m. EST on the 1st, and decreasing to 5:45 a.m. EST on the 28th.
Morning nautical twilight starts at 6:56 a.m. EST on the 1st, and decreasing to 6:19 a.m. EST on the 28th.

NASA Calendar of Planetary Events

    Date    Time    Event
Feb 01 	Th	    Venus: 5.7° E
    01  Th  1:24 pm Moon-Regulus: 0.9° S
    07  We 10:54 am Last Quarter
    07  We  2:47 pm Moon-Jupiter: 4.7° S
    09  Fr 12:12 am Moon-Mars: 4.8° S
    11  Su  9:16 am Moon Apogee: 405700 km
    11  Su  9:46 am Moon-Saturn: 2.7° S
    11  Su 11:40 am Mars-Antares: 5.1° N
    11  Su  6:21 pm Moon South Dec.: 20° S
    14  We  4:11 pm Moon Descending Node
    15  Th  3:52 pm Partial Solar Eclipse - S. America, Antarctica
    15  Th  4:05 pm New Moon
    17  Sa  7:08 am Mercury Superior Conj.
    23  Fr  3:09 am First Quarter
    23  Fr 12:07 pm Moon-Aldebaran: 0.7° S
    25  Su  3:07 pm Moon North Dec.: 20.1° N
    27  Tu  9:48 pm Moon Perigee: 363900 km
    27  Tu 12:28 pm Moon-Beehive: 2.3° N
    28  We 12:03 am Moon Ascending Node
Mar 01  Th          Venus: 12.4° E

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
     February, 2018    Local time zone: EST
     +-----------------------------------------------------------------------+
     | DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
     |      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
     +=======================================================================+
     |Thu  1| 08:01a  05:51p  09:49 | 06:57p  06:55a |      Rise 07:30p   97%|
     |Fri  2| 08:00a  05:52p  09:52 | 06:58p  06:54a |      Rise 08:43p   92%|
     |Sat  3| 07:59a  05:54p  09:54 | 07:00p  06:53a |      Rise 09:53p   85%|
     +------+-----------------------+----------------+-----------------------+
     |Sun  4| 07:58a  05:55p  09:57 | 07:01p  06:52a |      Rise 11:01p   76%|
     |Mon  5| 07:57a  05:57p  10:00 | 07:02p  06:51a |      Rise 12:06a   66%|
     |Tue  6| 07:55a  05:58p  10:02 | 07:04p  06:50a |      Rise 01:09a   57%|
     |Wed  7| 07:54a  06:00p  10:05 | 07:05p  06:49a |L Qtr Rise 02:10a   47%|
     |Thu  8| 07:53a  06:01p  10:08 | 07:06p  06:48a |      Rise 03:09a   37%|
     |Fri  9| 07:51a  06:02p  10:11 | 07:07p  06:46a |      Rise 04:05a   28%|
     |Sat 10| 07:50a  06:04p  10:13 | 07:09p  06:45a |      Rise 04:57a   20%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 11| 07:48a  06:05p  10:16 | 07:10p  06:44a |      Rise 05:45a   13%|
     |Mon 12| 07:47a  06:07p  10:19 | 07:11p  06:42a |      Rise 06:29a    8%|
     |Tue 13| 07:46a  06:08p  10:22 | 07:13p  06:41a |      Rise 07:07a    3%|
     |Wed 14| 07:44a  06:09p  10:25 | 07:14p  06:40a |      Rise 07:42a    1%|
     |Thu 15| 07:43a  06:11p  10:28 | 07:15p  06:38a |New   Set  06:07p    0%|
     |Fri 16| 07:41a  06:12p  10:31 | 07:16p  06:37a |      Set  07:09p    1%|
     |Sat 17| 07:40a  06:14p  10:34 | 07:18p  06:36a |      Set  08:13p    5%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 18| 07:38a  06:15p  10:37 | 07:19p  06:34a |      Set  09:17p   10%|
     |Mon 19| 07:36a  06:16p  10:40 | 07:20p  06:33a |      Set  10:23p   17%|
     |Tue 20| 07:35a  06:18p  10:43 | 07:22p  06:31a |      Set  11:29p   25%|
     |Wed 21| 07:33a  06:19p  10:46 | 07:23p  06:30a |      Set  12:38a   35%|
     |Thu 22| 07:32a  06:21p  10:49 | 07:24p  06:28a |      Set  01:46a   46%|
     |Fri 23| 07:30a  06:22p  10:52 | 07:25p  06:27a |F Qtr Set  02:54a   57%|
     |Sat 24| 07:28a  06:23p  10:55 | 07:27p  06:25a |      Set  04:00a   69%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 25| 07:27a  06:25p  10:58 | 07:28p  06:23a |      Set  04:59a   79%|
     |Mon 26| 07:25a  06:26p  11:01 | 07:29p  06:22a |      Set  05:52a   88%|
     |Tue 27| 07:23a  06:27p  11:04 | 07:31p  06:20a |      Set  06:38a   94%|
     |Wed 28| 07:22a  06:29p  11:07 | 07:32p  06:18a |      Set  07:17a   99%|
     +-----------------------------------------------------------------------+
     * Nautical Twilight
     ** Moonrise or moonset, whichever occurs between sunset and sunrise

 

09/20/2016 – Ephemeris – The twilight zone

Ephemeris for Tuesday, September 20th.  The Sun will rise at 7:28.  It’ll be up for 12 hours and 14 minutes, setting at 7:43.  The Moon, 3 days before last quarter, will rise at 10:29 this evening.

It’s getting a lot darker a lot earlier now than it did a month or so ago.  We see the same thing in the morning sky.  Now astronomical twilight, that’s when the last vestiges of the twilight glow disappear, ends before the time of sunset we had back in June.  Tonight that’s at 9:21 p.m., when the Sun reaches 18 degrees below the horizon.  Useful stargazing usually starts by nautical twilight which will occur at 8:46 p.m. when the Sun is 12 degrees down.  This is the time when navigators could see the bright stars and the horizon with their sextants to make a star fix.  It is a time when all the naked eye planets and the brighter constellations can be made out.   Twilight lasts the longest near the summer solstice due to the shallow angle of the Sun’s setting path.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Below is the twilight table for September through December.  This is a calendar function from Cartes du Ciel (Sky Charts), a free program, which can be downloaded from the panel on the right of this page.  This is, of course, for the Interlochen/Traverse City, Michigan area.  If you’re from somewhere else, download the program, and put in your location to create your own table.  The last two columns on the right are times that the sky will be dark, without moonlight.

Interlochen/ Traverse City			Time zone=EDT/EST
	Morning twilight		Evening twilight		Dark night
Date	Astronomical	Nautical	Nautical	Astronomical	Start	End
2016-09-01	5h26m	6h04m	21h27m	22h05m	22h05m	5h26m
2016-09-02	5h28m	6h06m	21h25m	22h03m	22h03m	5h28m
2016-09-03	5h29m	6h07m	21h23m	22h01m	22h01m	5h29m
2016-09-04	5h31m	6h09m	21h21m	21h59m	21h59m	5h31m
2016-09-05	5h33m	6h10m	21h19m	21h56m	22h24m	5h33m
2016-09-06	5h34m	6h11m	21h17m	21h54m	22h55m	5h34m
2016-09-07	5h36m	6h13m	21h15m	21h52m	23h29m	5h36m
2016-09-08	5h37m	6h14m	21h13m	21h50m	–	5h37m
2016-09-09	5h39m	6h15m	21h11m	21h48m	0h07m	5h39m
2016-09-10	5h40m	6h17m	21h09m	21h45m	0h50m	5h40m
2016-09-11	5h42m	6h18m	21h07m	21h43m	1h39m	5h42m
2016-09-12	5h43m	6h19m	21h05m	21h41m	2h34m	5h43m
2016-09-13	5h44m	6h20m	21h03m	21h39m	3h35m	5h44m
2016-09-14	5h46m	6h22m	21h01m	21h37m	4h40m	5h46m
2016-09-15	5h47m	6h23m	20h59m	21h35m	–	–
2016-09-16	5h49m	6h24m	20h57m	21h33m	–	–
2016-09-17	5h50m	6h26m	20h55m	21h31m	–	–
2016-09-18	5h51m	6h27m	20h53m	21h28m	–	–
2016-09-19	5h53m	6h28m	20h51m	21h26m	21h26m	21h47m
2016-09-20	5h54m	6h29m	20h49m	21h24m	21h24m	22h28m
2016-09-21	5h56m	6h31m	20h47m	21h22m	21h22m	23h15m
2016-09-22	5h57m	6h32m	20h45m	21h20m	21h20m	–
2016-09-23	5h58m	6h33m	20h43m	21h18m	21h18m	0h06m
2016-09-24	6h00m	6h34m	20h41m	21h16m	21h16m	1h02m
2016-09-25	6h01m	6h36m	20h39m	21h14m	21h14m	2h01m
2016-09-26	6h02m	6h37m	20h37m	21h12m	21h12m	3h03m
2016-09-27	6h04m	6h38m	20h36m	21h10m	21h10m	4h05m
2016-09-28	6h05m	6h39m	20h34m	21h08m	21h08m	5h08m
2016-09-29	6h06m	6h41m	20h32m	21h06m	21h06m	6h06m
2016-09-30	6h08m	6h42m	20h30m	21h04m	21h04m	6h08m
2016-10-01	6h09m	6h43m	20h28m	21h02m	21h02m	6h09m
2016-10-02	6h10m	6h44m	20h26m	21h00m	21h00m	6h10m
2016-10-03	6h11m	6h45m	20h24m	20h58m	20h58m	6h11m
2016-10-04	6h13m	6h47m	20h22m	20h56m	21h28m	6h13m
2016-10-05	6h14m	6h48m	20h21m	20h55m	22h04m	6h14m
2016-10-06	6h15m	6h49m	20h19m	20h53m	22h45m	6h15m
2016-10-07	6h16m	6h50m	20h17m	20h51m	23h31m	6h16m
2016-10-08	6h18m	6h52m	20h15m	20h49m	–	6h18m
2016-10-09	6h19m	6h53m	20h14m	20h47m	0h21m	6h19m
2016-10-10	6h20m	6h54m	20h12m	20h46m	1h19m	6h20m
2016-10-11	6h21m	6h55m	20h10m	20h44m	2h20m	6h21m
2016-10-12	6h23m	6h56m	20h08m	20h42m	3h26m	6h23m
2016-10-13	6h24m	6h58m	20h07m	20h40m	4h36m	6h24m
2016-10-14	6h25m	6h59m	20h05m	20h39m	5h49m	6h25m
2016-10-15	6h26m	7h00m	20h03m	20h37m	–	–
2016-10-16	6h28m	7h01m	20h02m	20h35m	–	–
2016-10-17	6h29m	7h03m	20h00m	20h34m	–	–
2016-10-18	6h30m	7h04m	19h58m	20h32m	20h32m	21h07m
2016-10-19	6h31m	7h05m	19h57m	20h31m	20h31m	21h58m
2016-10-20	6h33m	7h06m	19h55m	20h29m	20h29m	22h54m
2016-10-21	6h34m	7h07m	19h54m	20h27m	20h27m	23h54m
2016-10-22	6h35m	7h09m	19h52m	20h26m	20h26m	–
2016-10-23	6h36m	7h10m	19h51m	20h24m	20h24m	0h56m
2016-10-24	6h37m	7h11m	19h49m	20h23m	20h23m	1h59m
2016-10-25	6h39m	7h12m	19h48m	20h22m	20h22m	3h01m
2016-10-26	6h40m	7h14m	19h46m	20h20m	20h20m	4h02m
2016-10-27	6h41m	7h15m	19h45m	20h19m	20h19m	5h02m
2016-10-28	6h42m	7h16m	19h44m	20h17m	20h17m	6h02m
2016-10-29	6h43m	7h17m	19h42m	20h16m	20h16m	6h43m
2016-10-30	6h45m	7h18m	19h41m	20h15m	20h15m	6h45m
2016-10-31	6h46m	7h20m	19h40m	20h14m	20h14m	6h46m
2016-11-01	6h47m	7h21m	19h38m	20h12m	20h12m	6h47m
2016-11-02	6h48m	7h22m	19h37m	20h11m	20h42m	6h48m
2016-11-03	6h49m	7h23m	19h36m	20h10m	21h26m	6h49m
2016-11-04	6h51m	7h24m	19h35m	20h09m	22h14m	6h51m
2016-11-05	6h52m	7h26m	19h34m	20h08m	23h08m	6h52m
2016-11-06	5h53m	6h27m	18h33m	19h07m	23h07m	5h53m
2016-11-07	5h54m	6h28m	18h31m	19h06m	–	5h54m
2016-11-08	5h55m	6h29m	18h30m	19h04m	0h09m	5h55m
2016-11-09	5h56m	6h31m	18h29m	19h03m	1h15m	5h56m
2016-11-10	5h58m	6h32m	18h28m	19h03m	2h24m	5h58m
2016-11-11	5h59m	6h33m	18h27m	19h02m	3h36m	5h59m
2016-11-12	6h00m	6h34m	18h26m	19h01m	4h50m	6h00m
2016-11-13	6h01m	6h35m	18h26m	19h00m	–	–
2016-11-14	6h02m	6h36m	18h25m	18h59m	–	–
2016-11-15	6h03m	6h38m	18h24m	18h58m	–	–
2016-11-16	6h04m	6h39m	18h23m	18h57m	18h57m	19h38m
2016-11-17	6h06m	6h40m	18h22m	18h57m	18h57m	20h39m
2016-11-18	6h07m	6h41m	18h22m	18h56m	18h56m	21h43m
2016-11-19	6h08m	6h42m	18h21m	18h55m	18h55m	22h47m
2016-11-20	6h09m	6h43m	18h20m	18h55m	18h55m	23h52m
2016-11-21	6h10m	6h45m	18h20m	18h54m	18h54m	–
2016-11-22	6h11m	6h46m	18h19m	18h54m	18h54m	0h54m
2016-11-23	6h12m	6h47m	18h18m	18h53m	18h53m	1h56m
2016-11-24	6h13m	6h48m	18h18m	18h53m	18h53m	2h55m
2016-11-25	6h14m	6h49m	18h17m	18h52m	18h52m	3h54m
2016-11-26	6h15m	6h50m	18h17m	18h52m	18h52m	4h52m
2016-11-27	6h16m	6h51m	18h17m	18h52m	18h52m	5h51m
2016-11-28	6h17m	6h52m	18h16m	18h51m	18h51m	6h17m
2016-11-29	6h18m	6h53m	18h16m	18h51m	18h51m	6h18m
2016-11-30	6h19m	6h54m	18h16m	18h51m	18h51m	6h19m
2016-12-01	6h20m	6h55m	18h15m	18h50m	19h11m	6h20m
2016-12-02	6h21m	6h56m	18h15m	18h50m	20h03m	6h21m
2016-12-03	6h22m	6h57m	18h15m	18h50m	20h59m	6h22m
2016-12-04	6h23m	6h58m	18h15m	18h50m	22h00m	6h23m
2016-12-05	6h24m	6h59m	18h15m	18h50m	23h03m	6h24m
2016-12-06	6h25m	7h00m	18h15m	18h50m	–	6h25m
2016-12-07	6h26m	7h01m	18h15m	18h50m	0h08m	6h26m
2016-12-08	6h26m	7h02m	18h15m	18h50m	1h17m	6h26m
2016-12-09	6h27m	7h03m	18h15m	18h50m	2h26m	6h27m
2016-12-10	6h28m	7h03m	18h15m	18h50m	3h40m	6h28m
2016-12-11	6h29m	7h04m	18h15m	18h50m	4h54m	6h29m
2016-12-12	6h30m	7h05m	18h15m	18h51m	6h09m	6h30m
2016-12-13	6h30m	7h06m	18h15m	18h51m	–	–
2016-12-14	6h31m	7h06m	18h16m	18h51m	–	–
2016-12-15	6h32m	7h07m	18h16m	18h51m	18h51m	19h21m
2016-12-16	6h32m	7h08m	18h16m	18h52m	18h52m	20h28m
2016-12-17	6h29m	7h04m	18h13m	18h48m	18h48m	21h35m
2016-12-18	6h30m	7h05m	18h13m	18h48m	18h48m	22h40m
2016-12-19	6h30m	7h06m	18h13m	18h49m	18h49m	23h44m
2016-12-20	6h31m	7h06m	18h14m	18h49m	18h49m	–
2016-12-21	6h31m	7h07m	18h14m	18h50m	18h50m	0h45m
2016-12-22	6h32m	7h07m	18h15m	18h50m	18h50m	1h46m
2016-12-23	6h32m	7h07m	18h15m	18h51m	18h51m	2h44m
2016-12-24	6h32m	7h08m	18h16m	18h51m	18h51m	3h43m
2016-12-25	6h33m	7h08m	18h17m	18h52m	18h52m	4h40m
2016-12-26	6h33m	7h09m	18h17m	18h53m	18h53m	5h37m
2016-12-27	6h34m	7h09m	18h18m	18h53m	18h53m	6h32m
2016-12-28	6h34m	7h09m	18h19m	18h54m	18h54m	6h34m
2016-12-29	6h34m	7h09m	18h19m	18h55m	18h55m	6h34m
2016-12-30	6h34m	7h10m	18h20m	18h56m	18h56m	6h34m
2016-12-31	6h34m	7h10m	18h21m	18h56m	19h53m	6h34m

03/03/2016 – Ephemeris – How to spot Zodiacal Light

Ephemeris for Thursday, March 3rd.  The Sun will rise at 7:15.  It’ll be up for 11 hours and 17 minutes, setting at 6:33.   The Moon, 2 days past last quarter, will rise at 4:00 tomorrow morning.

There is a faint glow in the west that lingers after the end of twilight. It is visible to the careful observer.  It’s Zodiacal Light, the reflected glow from countless bits of dust in the plane of the solar system.  Its glow can be seen after twilight officially ends at 8:11 p.m.  You’ll need to go to a spot with no towns or cities immediately to the west of you.  The glow will appear as a thin pyramidal glow tilted to the left.  It’s very difficult to find the first time, but once seen you’ll easily find it again.  Zodiacal Light is easiest seen on spring evenings and autumn mornings when the ecliptic, the path of the planets and zodiac are nearest to vertical.  The farther south one goes the easier it is to see.  I first saw it when I was stationed in the Air Force in Louisiana.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Zodiacal Light and Comet Hale-Bopp April 1997. My image.

Zodiacal Light and Comet Hale-Bopp April 1997. Enhanced contrast.

I find I have better luck photographing Zodiacal Light if I take  picture in its general direction of something else.

 

08/29/2014 – Ephemeris – Twilight is shorter now than it was in June

Ephemeris for Friday, August 29th.  The sun will rise at 7:01.  It’ll be up for 13 hours and 22 minutes, setting at 8:24.   The moon, half way from new to first quarter, will set at 10:09 this evening.

Here we are at the end of August already.  We have one more night to view the Milky Way in darkness after the moon sets, because the Moon sets at the very end of astronomical twilight.  By the way, astronomical twilight starts and ends when the sun is 18 degrees below the horizon, and the actual twilight glow is completely gone.  The sun sets more than an hour before it did in late June, which means that it gets dark much earlier.  Twilight lasted much longer in June than it does now because the Earth’s rotation now drops the sun below the horizon at a steeper angle.   As a matter of fact while the sun sets an hour earlier now than in June, twilight ends two hours earlier.  It sneaks up on you if you’re not paying attention to it.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Distance the Sun must travel from the horizon to 18 degrees below tonight, August 29, 2014. Created using Stellarium.

Distance the Sun must travel from the horizon to 18 degrees below, the night after the June solstice, June 22, 2014. Created using Stellarium.