Posts Tagged ‘2021’

09/10/2021 – Ephemeris – Rescheduled virtual Sleeping Bear Dunes/GTAS star party set for tomorrow, Saturday night the 11th

September 10, 2021 Comments off

This is Bob Moler with Ephemeris for Friday, September 10th. Today the Sun will be up for 12 hours and 46 minutes, setting at 8:02, and it will rise tomorrow at 7:17. The Moon, 3 days before first quarter, will set at 10:05 this evening.

Tomorrow night the Sleeping Bear Dunes National Lakeshore and the Grand Traverse Astronomical Society (GTAS) will host an online star party starting around 9 pm via the Zoom app available for Android smartphones, iPhones and computers. This is rescheduled from last week due to clouds. Instructions for joining are on the society’s website, Images will be captured live from Northwestern Michigan College’s Joseph H Rogers Observatory. The images will be pretty much what is seen at the telescope eyepiece, and definitely not Hubble Space Telescope quality, which take weeks or months to process. Visible will be the five-day-old Moon, Venus, Jupiter, Saturn and the wonders of the Milky Way.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.


During the GTAS board meeting, September 3rd, just before the canceled  star party, it was decided to hold off the decision on in person star parties until spring of 2022. We’ll follow the state of the pandemic in our area over the winter and see where we stand. Star parties at the Northwestern Michigan College’s Joseph H. Rogers Observatory could start in March. Star parties at the Sleeping Bear Dunes National Lakeshore have in the past started in April.

We may still use imagers on our telescopes to capture celestial objects for display on laptop computers rather than viewing through the eyepiece. The society has two imagers, and the Observatory another. The society’s imagers can be used on society’s and members telescopes. This will solve the problems of having to sanitize telescope eyepieces between observers. At this point, I’m not sure what sanitizing products do to the delicate anti-reflective coatings on eyepieces.

We will also pay more attention to viewing the heavens with the naked eye or binoculars that people may have. Bring your own. Learning the constellations is always the best way to be introduced to astronomy, and the only way, up until 411 years ago. And binoculars are a great first telescope.

02/01/2021 – Ephemeris – Previewing February Skies

February 1, 2021 Comments off

This is Ephemeris for Monday, February 1st. Today the Sun will be up for 9 hours and 50 minutes, setting at 5:51, and it will rise tomorrow at 8:00. The Moon, 3 days before last quarter, will rise at 10:33 this evening. | February is the shortest month, even so the daylight hours throughout the month will be getting longer. Daylight hours will increase from 9 hours and 50 minutes today to 11 hours and 7 minutes on the 28th. The sunrise time will decrease from 8:01 today to 7:21 at months end. The sunset times will increase from 5:51 today to 6:29 on the 28th. Along with that the altitude of the Sun at noon will increase from 28.4 degrees today to 37.6 degrees at month’s end. It will be a degree lower for folks in the Straits area because they are a degree of latitude farther north. Local noon, by the way for Interlochen and Traverse City is about 12:56 p.m.

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


February Evening Star Chart

Star Chart for February 2021 (9 p.m. EST February 15, 2021). 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). To duplicate the star positions on a planisphere (rotating star finder) you may have to set it to 1 hour 45 minutes earlier than the current time.

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 (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, check the Wednesday planet posts on this blog.

February Morning Star Chart

February Morning Star Chart

Star Chart for February mornings 2021 (6 a.m. EST February 15, 2021). Created using my LookingUp program. Click on image to enlarge.

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.
  • 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.

Twilight Limits, Nautical and Astronomical

Morning twilight Evening twilight Dark night Moon
Date Astro. Nautical Nautical Astro. Start End Illum.
2021-02-01 6h22m 6h56m 18h56m 19h30m 19h30m 22h33m 0.78
2021-02-02 6h21m 6h55m 18h57m 19h31m 19h31m 23h48m 0.67
2021-02-03 6h20m 6h54m 18h59m 19h33m 19h33m 0.56
2021-02-04 6h19m 6h53m 19h00m 19h34m 19h34m 1h03m 0.45
2021-02-05 6h18m 6h52m 19h01m 19h35m 19h35m 2h20m 0.34
2021-02-06 6h16m 6h50m 19h02m 19h36m 19h36m 3h35m 0.23
2021-02-07 6h15m 6h49m 19h04m 19h38m 19h38m 4h48m 0.15
2021-02-08 6h14m 6h48m 19h05m 19h39m 19h39m 5h54m 0.08
2021-02-09 6h13m 6h47m 19h06m 19h40m 19h40m 6h13m 0.03
2021-02-10 6h12m 6h46m 19h08m 19h41m 19h41m 6h12m 0
2021-02-11 6h10m 6h44m 19h09m 19h43m 19h43m 6h10m 0
2021-02-12 6h09m 6h43m 19h10m 19h44m 19h44m 6h09m 0.02
2021-02-13 6h08m 6h42m 19h11m 19h45m 20h14m 6h08m 0.06
2021-02-14 6h06m 6h40m 19h13m 19h47m 21h19m 6h06m 0.12
2021-02-15 6h05m 6h39m 19h14m 19h48m 22h22m 6h05m 0.19
2021-02-16 6h04m 6h37m 19h15m 19h49m 23h25m 6h04m 0.27
2021-02-17 6h02m 6h36m 19h17m 19h50m 6h02m 0.35
2021-02-18 6h01m 6h34m 19h18m 19h52m 0h27m 6h01m 0.45
2021-02-19 5h59m 6h33m 19h19m 19h53m 1h30m 5h59m 0.54
2021-02-20 5h58m 6h32m 19h21m 19h54m 2h33m 5h58m 0.64
2021-02-21 5h56m 6h30m 19h22m 19h56m 3h35m 5h56m 0.73
2021-02-22 5h55m 6h28m 19h23m 19h57m 4h34m 5h55m 0.81
2021-02-23 5h53m 6h27m 19h24m 19h58m 5h28m 5h53m 0.89
2021-02-24 5h52m 6h25m 19h26m 19h59m 0.94
2021-02-25 5h50m 6h24m 19h27m 20h01m 0.98
2021-02-26 5h48m 6h22m 19h28m 20h02m 1
2021-02-27 5h47m 6h20m 19h30m 20h03m 0.99
2021-02-28 5h45m 6h19m 19h31m 20h05m 20h05m 20h16m 0.95

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:

NASA Calendar of Planetary Events

Date         Time     Event
Feb  1  Mo            Venus: 13° W
     3  We   2:33 pm  Moon Perigee: 370,100 km
     4  Th  12:37 pm  Last Quarter
     6  Sa   7:29 pm  Moon Descending Node
     8  Mo   8:39 am  Mercury Inferior Conjunction
     8  Mo  10:34 am  Moon South Dec.: 25° S
    11  Th   2:06 pm  New Moon
    18  Th   5:22 am  Moon Apogee: 404,500 km
    18  Th   5:47 pm  Moon-Mars: 4.1° N
    19  Fr   1:47 pm  First Quarter
    20  Sa   8:44 pm  Moon Ascending Node
    22  Mo   7:12 pm  Moon North Dec.: 25.1° N
    23  Tu   2:38 am  Mercury-Saturn: 4° N
    24  We   7:16 pm  Moon-Beehive: 2.5° S
    27  Sa   3:17 am  Full Moon

All event times are given for UTC-5:00: Eastern Standard or Daylight Time

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),

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, 2021    Local time zone: EST
|Mon  1| 08:01a  05:51p  09:50 | 06:57p  06:55a |      Rise 10:33p   79%|
|Tue  2| 08:00a  05:53p  09:53 | 06:59p  06:54a |      Rise 11:48p   69%|
|Wed  3| 07:59a  05:54p  09:55 | 07:00p  06:53a |      Rise 01:03a   58%|
|Thu  4| 07:57a  05:56p  09:58 | 07:01p  06:52a |L Qtr Rise 02:19a   47%|
|Fri  5| 07:56a  05:57p  10:00 | 07:03p  06:51a |      Rise 03:35a   36%|
|Sat  6| 07:55a  05:59p  10:03 | 07:04p  06:50a |      Rise 04:48a   25%|
|Sun  7| 07:54a  06:00p  10:06 | 07:05p  06:48a |      Rise 05:53a   16%|
|Mon  8| 07:52a  06:01p  10:09 | 07:06p  06:47a |      Rise 06:49a    9%|
|Tue  9| 07:51a  06:03p  10:11 | 07:08p  06:46a |      Rise 07:35a    4%|
|Wed 10| 07:49a  06:04p  10:14 | 07:09p  06:45a |      Rise 08:11a    1%|
|Thu 11| 07:48a  06:06p  10:17 | 07:10p  06:43a |New   Set  05:57p    0%|
|Fri 12| 07:47a  06:07p  10:20 | 07:12p  06:42a |      Set  07:07p    2%|
|Sat 13| 07:45a  06:08p  10:23 | 07:13p  06:41a |      Set  08:14p    5%|
|Sun 14| 07:44a  06:10p  10:26 | 07:14p  06:39a |      Set  09:19p   11%|
|Mon 15| 07:42a  06:11p  10:29 | 07:15p  06:38a |      Set  10:22p   17%|
|Tue 16| 07:41a  06:13p  10:32 | 07:17p  06:37a |      Set  11:24p   25%|
|Wed 17| 07:39a  06:14p  10:34 | 07:18p  06:35a |      Set  12:27a   34%|
|Thu 18| 07:38a  06:15p  10:37 | 07:19p  06:34a |      Set  01:30a   43%|
|Fri 19| 07:36a  06:17p  10:40 | 07:21p  06:32a |F Qtr Set  02:32a   52%|
|Sat 20| 07:34a  06:18p  10:43 | 07:22p  06:31a |      Set  03:34a   61%|
|Sun 21| 07:33a  06:20p  10:46 | 07:23p  06:29a |      Set  04:33a   71%|
|Mon 22| 07:31a  06:21p  10:49 | 07:25p  06:28a |      Set  05:28a   79%|
|Tue 23| 07:30a  06:22p  10:52 | 07:26p  06:26a |      Set  06:15a   87%|
|Wed 24| 07:28a  06:24p  10:55 | 07:27p  06:25a |      Set  06:56a   93%|
|Thu 25| 07:26a  06:25p  10:58 | 07:28p  06:23a |      Set  07:30a   98%|
|Fri 26| 07:24a  06:26p  11:01 | 07:30p  06:21a |      Set  07:59a  100%|
|Sat 27| 07:23a  06:28p  11:05 | 07:31p  06:20a |Full  Rise 06:59p   99%|
|Sun 28| 07:21a  06:29p  11:08 | 07:32p  06:18a |      Rise 08:16p   96%|
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Created using my LookingUp for DOS output as HTML.