07/30/2021 – Ephemeris – Previewing August skies

This is Bob Moler with Ephemeris for Friday, July 30th. Today the Sun will be up for 14 hours and 43 minutes, setting at 9:10, and it will rise tomorrow at 6:28. The Moon, 1 day before last quarter, will rise at 12:38 tomorrow morning.

Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 38 minutes on the 1st to 13 hours 16 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 Sunday to just over 53 degrees on the 31st. Straits area listeners can subtract one more degree from those angles, but their daylight hours will be a few minutes longer. Local noon, when the Sun is due south, is about 1:43 p.m. The Perseid meteor shower will reach its peak at between 3 and 6 p.m. on the 12th. That means that more than likely the early mornings of the 12th and 13th will be equally good for viewing them. I tend to prefer viewing before the peak, if given a choice.

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.

Addendum

August Evening Star Chart

Star Chart for August 2020 (10 pm EDT, August 15, 2021). Click on image to enlarge it. 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

Star Chart for August mornings, (5 a.m. EDT, August 15, 2021). 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.
2021-08-01	4h31m	5h19m	22h26m	23h15m	23h15m	1h00m	0.35
2021-08-02	4h32m	5h20m	22h25m	23h13m	23h13m	1h25m	0.26
2021-08-03	4h34m	5h22m	22h23m	23h11m	23h11m	1h55m	0.18
2021-08-04	4h36m	5h23m	22h21m	23h08m	23h08m	2h31m	0.11
2021-08-05	4h38m	5h25m	22h20m	23h06m	23h06m	3h16m	0.06
2021-08-06	4h40m	5h26m	22h18m	23h04m	23h04m	4h09m	0.02
2021-08-07	4h42m	5h28m	22h16m	23h02m	23h02m	4h42m	0
2021-08-08	4h44m	5h29m	22h14m	23h00m	23h00m	4h44m	0
2021-08-09	4h46m	5h31m	22h13m	22h58m	22h58m	4h46m	0.03
2021-08-10	4h48m	5h32m	22h11m	22h55m	22h55m	4h48m	0.08
2021-08-11	4h50m	5h34m	22h09m	22h53m	22h53m	4h50m	0.15
2021-08-12	4h51m	5h35m	22h07m	22h51m	23h13m	4h51m	0.24
2021-08-13	4h53m	5h37m	22h05m	22h49m	23h36m	4h53m	0.34
2021-08-14	4h55m	5h38m	22h03m	22h47m	–	4h55m	0.45
2021-08-15	4h57m	5h40m	22h02m	22h44m	0h03m	4h57m	0.57
2021-08-16	4h59m	5h41m	22h00m	22h42m	0h34m	4h59m	0.68
2021-08-17	5h01m	5h43m	21h58m	22h40m	1h13m	5h01m	0.78
2021-08-18	5h02m	5h44m	21h56m	22h38m	2h02m	5h02m	0.87
2021-08-19	5h04m	5h46m	21h54m	22h36m	3h02m	5h04m	0.94
2021-08-20	5h06m	5h47m	21h52m	22h33m	4h12m	5h06m	0.98
2021-08-21	5h08m	5h49m	21h50m	22h31m	–	–	1
2021-08-22	5h09m	5h50m	21h48m	22h29m	–	–	0.99
2021-08-23	5h11m	5h52m	21h46m	22h27m	–	–	0.97
2021-08-24	5h13m	5h53m	21h44m	22h24m	–	–	0.92
2021-08-25	5h15m	5h54m	21h42m	22h22m	–	–	0.86
2021-08-26	5h16m	5h56m	21h40m	22h20m	22h20m	22h40m	0.78
2021-08-27	5h18m	5h57m	21h38m	22h18m	22h18m	23h01m	0.69
2021-08-28	5h20m	5h59m	21h36m	22h15m	22h15m	23h25m	0.6
2021-08-29	5h21m	6h00m	21h34m	22h13m	22h13m	23h53m	0.51
2021-08-30	5h23m	6h01m	21h32m	22h11m	22h11m	–	0.42
2021-08-31	5h24m	6h03m	21h30m	22h09m	22h09m	0h26m	0.32

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  Su            Venus: 33.1° E
     1  Su  10:00 am  Mercury Superior Conj.
     2  Mo   1:24 am  Saturn Opposition
     2  Mo   3:35 am  Moon Apogee: 404400 km
     2  Mo  10:51 pm  Moon Ascending Node
     5  Th  12:46 pm  Moon North Dec.: 25.7° N
     8  Su   9:50 am  New Moon
    11  We   3:00 am  Moon-Venus: 4.4° S
    12  Th   3:11 pm  Perseid Shower: ZHR = 90
    15  Su  11:20 am  First Quarter
    16  Mo  12:04 pm  Moon Descending Node
    17  Tu   5:23 am  Moon Perigee: 369100 km
    18  We   6:24 pm  Moon South Dec.: 25.8° S
    18  We  11:03 pm  Mercury-Mars: 0.1° N
    19  Th   7:05 pm  Jupiter Opposition
    20  Fr   6:19 pm  Moon-Saturn: 3.8° N
    22  Su  12:52 am  Moon-Jupiter: 4.1° N
    22  Su   8:02 am  Full Moon
    29  Su  10:22 pm  Moon Apogee: 404100 km
    30  Mo   1:13 am  Moon Ascending Node
    30  Mo   3:13 am  Last Quarter
Sep  1  We            Venus: 39.9° 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

                  Ephemeris of Sky Events for Interlochen/TC
August, 2021    Local time zone: EDT
+-----------------------------------------------------------------------+
| DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
|      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
+=======================================================================+
|Sun  1| 06:29a  09:08p  14:38 | 10:23p  05:13a |      Rise 01:25a   36%|
|Mon  2| 06:30a  09:06p  14:36 | 10:21p  05:15a |      Rise 01:55a   28%|
|Tue  3| 06:31a  09:05p  14:33 | 10:20p  05:16a |      Rise 02:31a   20%|
|Wed  4| 06:32a  09:04p  14:31 | 10:18p  05:18a |      Rise 03:16a   13%|
|Thu  5| 06:33a  09:02p  14:29 | 10:16p  05:19a |      Rise 04:09a    7%|
|Fri  6| 06:35a  09:01p  14:26 | 10:14p  05:21a |      Rise 05:11a    3%|
|Sat  7| 06:36a  09:00p  14:23 | 10:13p  05:22a |      Rise 06:18a    1%|
+------+-----------------------+----------------+-----------------------+
|Sun  8| 06:37a  08:58p  14:21 | 10:11p  05:24a |New   Set  09:35p    0%|
|Mon  9| 06:38a  08:57p  14:18 | 10:09p  05:25a |      Set  10:03p    2%|
|Tue 10| 06:39a  08:55p  14:16 | 10:07p  05:27a |      Set  10:27p    7%|
|Wed 11| 06:40a  08:54p  14:13 | 10:05p  05:28a |      Set  10:50p   13%|
|Thu 12| 06:42a  08:52p  14:10 | 10:04p  05:30a |      Set  11:13p   22%|
|Fri 13| 06:43a  08:51p  14:08 | 10:02p  05:31a |      Set  11:36p   32%|
|Sat 14| 06:44a  08:49p  14:05 | 10:00p  05:33a |      Set  12:03a   43%|
+------+-----------------------+----------------+-----------------------+
|Sun 15| 06:45a  08:48p  14:02 | 09:58p  05:34a |F Qtr Set  12:34a   54%|
|Mon 16| 06:46a  08:46p  13:59 | 09:56p  05:36a |      Set  01:13a   65%|
|Tue 17| 06:47a  08:44p  13:56 | 09:54p  05:37a |      Set  02:02a   76%|
|Wed 18| 06:49a  08:43p  13:54 | 09:52p  05:39a |      Set  03:02a   85%|
|Thu 19| 06:50a  08:41p  13:51 | 09:50p  05:40a |      Set  04:11a   92%|
|Fri 20| 06:51a  08:39p  13:48 | 09:48p  05:42a |      Set  05:26a   97%|
|Sat 21| 06:52a  08:38p  13:45 | 09:46p  05:43a |      Set  06:40a  100%|
+------+-----------------------+----------------+-----------------------+
|Sun 22| 06:53a  08:36p  13:42 | 09:45p  05:44a |Full  Rise 09:15p  100%|
|Mon 23| 06:54a  08:34p  13:39 | 09:43p  05:46a |      Rise 09:39p   97%|
|Tue 24| 06:56a  08:33p  13:36 | 09:41p  05:47a |      Rise 10:00p   93%|
|Wed 25| 06:57a  08:31p  13:34 | 09:39p  05:49a |      Rise 10:20p   87%|
|Thu 26| 06:58a  08:29p  13:31 | 09:37p  05:50a |      Rise 10:40p   79%|
|Fri 27| 06:59a  08:27p  13:28 | 09:35p  05:52a |      Rise 11:01p   71%|
|Sat 28| 07:00a  08:26p  13:25 | 09:33p  05:53a |      Rise 11:25p   62%|
+------+-----------------------+----------------+-----------------------+
|Sun 29| 07:02a  08:24p  13:22 | 09:31p  05:54a |      Rise 11:53p   53%|
|Mon 30| 07:03a  08:22p  13:19 | 09:29p  05:56a |L Qtr Rise 12:26a   43%|
|Tue 31| 07:04a  08:20p  13:16 | 09:27p  05:57a |      Rise 01:07a   34%|
+-----------------------------------------------------------------------+
* Nautical Twilight
** Moonrise or moonset, whichever occurs between sunrise and sunset

Generated using my LookingUp for DOS program.

07/29/2021 – Ephemeris – Anishinaabe constellation of their hero

This is Bob Moler with Ephemeris for Thursday, 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 before last quarter, will rise at 12:17 tomorrow morning. | Tuesday I talked about the constellation Scorpius the scorpion now seen low in the southern sky in the evening. To me, the stars here make a very good scorpion. Scorpius was invented by people of the Middle East, where scorpions are plentiful. The Anishinaabe native peoples of our area, however, saw one of their legendary hero figures, Nenabozho*. In the sky, the arc of three stars at the front of the scorpion and to the right of the bright star Antares is his bow. He is shooting an arrow toward the receding Great Panther or Curly Tail a constellation of spring whose curl of a tail is the head of the constellation Leo, now lost in the evening twilight in the west. Nenabozho was a hero in their creation stories, a trickster who was often seen as a rabbit.

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.

Addenda

* Nenabozho is pronounced like Nana-bouz-hou, though different tribes pronounced it differently. I could not find Nenabozho and its various other transliterations, one of which was Nanaboozhoo in the Ojibwe People’s Dictionary (https://ojibwe.lib.umn.edu/). However, since he occasionally shape-shifted into being a rabbit his name includes a part of the name for rabbit, waabooz. That entry had several audio examples. That’s how I got the pronunciation for the radio program.

Finder chart

Animated finder for the Anishinaabe constellation of Nenabozho showing the unannotated star field, the Western constellation of Scorpius and Nenabozho. Created using Stellarium (both star lore images are embedded in Stellarium). The Anishinaabe image is embedded in Stellarium and is from Ojibwe Giizhig Anung Masinaaigan – Ojibiwe Sky Star Map created by A. Lee, W. Wilson, and C. Gawboy.

 

07/28/2021 – Ephemeris – Searching for the naked-eye planets on the last Wednesday in July

This is Ephemeris for Wednesday, July 28th. Today the Sun will be up for 14 hours and 48 minutes, setting at 9:13, and it will rise tomorrow at 6:25. The Moon, 3 days before last quarter, will rise at 11:58 this evening.

Let’s search for the naked-eye planets for this week. Venus can be spotted low in the west-northwest twilight by 9:45 pm. It will set at 10:39 pm. Venus will be spending the rest of summer low in the western sky, and not be as conspicuous as it usually is as the Evening Star. Mars, I believe, is too faint and close to the Sun to be seen from northern latitudes. Saturn will be seen low in the southeast in the evening, with Jupiter rising later. Saturn, 5 days from opposition, that is being opposite the Sun in the sky and closest to Earth, will rise at 9:21 pm. Brighter Jupiter will rise at 10:12 pm, both planets will rise in the east-southeast. By 5:30 am, these two planets will be in the southwestern sky in the morning twilight.

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.

Addendum

Venus in evening twilight in the west at 10 pm, July 28, 2021. Created using Stellarium.

Jupiter and Saturn low in the southeast at 11 pm. Created using Stellarium.

The waning gibbous Moon as it might be seen in binoculars or small telescope at 5:30 am, July 29, 2021. Created using Stellarium.

Telescopic view of the bright planets (north up) as they would be seen in a small telescope, with the same magnification, this evening, July 28, 2021. Apparent diameters: Venus, 12.58″; Saturn 18.59″, its rings 43.31″; Jupiter, 48.28″. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. 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 28, 2021. The night ends on the left with sunrise on the 29th. Click on the image to enlarge. Created using my LookingUp program.

07/27/2021 – Ephemeris – The celestial scorpion crawls over the southern horizon

This is Ephemeris for Tuesday, July 27th. Today the Sun will be up for 14 hours and 50 minutes, setting at 9:14, and it will rise tomorrow at 6:24. The Moon, halfway from full to last quarter, will rise at 11:37 this evening.

There’s a large constellation located low in the south around 10:30, 11 o’clock tonight. It’s Scorpius the scorpion. Its brightest star is Antares in its heart, a red giant star, that I used to get calls about from time to time as being a UFO. From Antares to the right is a star, then a vertical arc of three stars that is its head. The Scorpion’s tail is a line of stars running down to the left of Antares, swooping to the horizon before coming back up and ending in a pair of stars that portray his poisonous stinger. Scorpius looks huge lying on the southern horizon. But if you go south, Scorpius will be higher in the sky, and will look smaller. Being close to the horizon from here, Scorpius shares with the rising and setting sun and moon the illusion of increased size.

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.

Addendum

Scorpius animated finder for 10:30 pm July 27th. The Arabs saw a bigger scorpion with Antares in the upper part of its body, the arc of three stars near its head and its claws extending to Zubeneschamali (North Claw) and Zubenelgenubi (South Claw). The latter two stars belong to Libra the scales. Click on the image to enlarge it. Created using Stellarium and GIMP.

07/26/2021 – Ephemeris – Albireo, a colorful double star in Cygnus the swan

This is Ephemeris for Monday, July 26th. Today the Sun will be up for 14 hours and 52 minutes, setting at 9:15, and it will rise tomorrow at 6:23. The Moon, 3 days past full, will rise at 11:15 this evening.

Alberio is the name given to the star that is in the beak of the constellation of Cygnus the swan, which is high in the east these evenings. It is also at the foot of the asterism or informal constellation of the Northern Cross. To the naked eye Alberio looks like a single star, however even in small telescopes* its true nature is revealed. It is a double star whose individual star colors are strikingly different Its brightest star is yellow, and the dimmer star is blue. While star colors are subtle, these two, due to their apparent closeness, make an obvious color contrast. Unlike what your interior decorator says: In stars blue is hot, yellow, orange and red are cool. Also, it turns out that Alberio’s component stars don’t orbit each other. It is what is called an optical double. The blue star is a bit farther away than the yellow one, though they’re both around 430 light years away.

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.

* It will take at least about 20 power magnification to split. Binoculars won’t do it.

Addendum

Animated Albireo finder chart. Albireo is located in the head of Cygnus the swan, or at the base of the Northern Cross. Tagged stars are, beside Albireo, the stars of the Summer Triangle: Deneb, Vega and Altair plus the star at the junction of the upright and crosspiece of the cross, Sadr. Created using Stellarium.

Albireo, captured at high magnification by the staff of the Smithsonian Institution.

07/23/2021 – Ephemeris – The first exoplanet* found

This is Bob Moler with Ephemeris for Friday, 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, at full today, will rise at 9:35 this evening.

In 1995 the first planet was found that orbits another star. It was 51 Pegasi b. That’s the star labeled number 51 in the constellation Pegasus, the flying horse. It was found because it tugged on its star as it orbited it. The planet was detected by the Doppler method, the same method that the police can tell if you’re speeding. A planet doesn’t orbit the center of the star, but the center of their combined mass. It turned out That 51 Pegasi b is a very large planet, half the mass of Jupiter, orbiting its star every 4 ½ days. Its discovery threw everything we thought we knew about planetary system evolution into a cocked hat. Planets just don’t stay nicely in their orbits like we thought. They move in and out! As this planet moved in toward its star, it would have ejected any of the inner planets out of the system.

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.

* A planet was found several years before, orbiting a pulsar, which is a neutron star. Apparently, planets orbiting dead stars don’t count.

Addendum

An artist’s depiction of what exoplanet Pegasus 51b and its star might look like. Credit: ESO (European Southern Observatory) / M. Kornmesser.

07/22/2021 – Ephemeris – Hubble’s trouble is fixed

This is Bob Moler with Ephemeris for Thursday, 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, 1 day before full, will set at 5:18 tomorrow morning.

Folks at NASA are breathing a sigh of relief. After a month when one of its computers failed in the Hubble Space Telescope, ground controllers were able to diagnose that the problem was actually in the computer and not somewhere else. They switched to a backup computer. This wasn’t the main computer, but the one that ran the instruments. Hubble resumed operations this past Sunday. Hubble’s more or less replacement, the James Webb Space Telescope is many years overdue to be launched, and is expected to be launched later this year by the European Space Agency from French Guiana, as their contribution to the project. The Webb telescope operates in the infrared, while Hubble operates mostly in visible light.

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.

Addendum

The Hubble Space Telescope after its last servicing mission. Credit: NASA.

 

Full scale model of the James Webb Space Telescope at Goddard Space Flight Center. Note its scale with the people in front of it.

07/21/2021 – Ephemeris – Let’s search for the naked-eye planets for this week

This is Ephemeris for Wednesday, 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, 2 days before full, will set at 4:13 tomorrow morning.

Let’s search for the naked-eye planets for this week. Venus can be spotted low in the west-northwest twilight by 10 pm. It will set at 10:49 pm. Venus will be spending the rest of summer low in the western sky, and not be as conspicuous as it usually is as the Evening Star. Mars’ visibility is a real problem. It will be to the right and below Venus in the evening, and will set at 10:35 pm. It’s much dimmer than Venus. The bright star Regulus will be just below and left of Venus tonight. Saturn will be seen low in the southeast in the evening, with Jupiter rising later and best in the morning sky. Saturn will rise at 9:49 pm. Brighter Jupiter will rise at 10:41 pm, both in the east-southeast. By 5:30 am, these two planets will be in the southern sky in the morning twilight.

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.

Addendum

Venus and Mars in evening twilight at 10 pm, about 40 minutes after sunset, tonight, Julyn21, 2021. Regulus, the first magnitude star in Leo, will appear just below and left of Venus. Click on the image to enlarge it. Created using Stellarium.

The Gibbous Moon, Saturn, and Jupiter at 11 pm, tonight, July 21, 2021. The Moon is above the spout in the asterism of the Teapot in Sagittarius. Click on the image to enlarge it. Created using Stellarium.

The gibbous Moon as it will look like in binoculars or small telescope tonight, July 21, 2021. Created using Stellarium.

Jupiter and Saturn with the bright autumn star Fomalhaut, seen in morning twilight at 5:30. Created using Stellarium.

Telescopic view of the bright planets (north up), with the same magnification, this evening, July 21, 2021. Apparent diameters: Venus, 12.17″; Saturn 18.56″, its rings 43.24″; Jupiter, 47.70″. Mars has an apparent diameter of only 3.71″ and is not represented. The ” symbol means seconds of arc (1/3600th of a degree.) Click on the image to enlarge it. 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 21, 2021. The night ends on the left with sunrise on the 22nd. Click on the image to enlarge. Created using my LookingUp program.

 

07/20/2021 – Ephemeris – Another giant leap for billionaires

This is Bob Moler with Ephemeris for Tuesday, 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, halfway from first quarter to full, will set at 3:18 tomorrow morning.

Today is the fifty-second anniversary of Neil Armstrong and Buzz Aldrin’s first steps on the Moon with Apollo 11 and the 45th anniversary of the first robotic spacecraft to soft land on Mars, Viking 1. And if all goes well, it will be the first crewed flight of Blue Origin’s New Shepard rocket with capsule up to over 100 kilometers altitude for 5 minutes of weightlessness. On board will be Jeff Bezos, CEO of Blue Origin, founder of Amazon, his brother, and 82-year-old Wally Funk, one of the Mercury 13 women, who took all the physical and mental tests that the Mercury 7 astronauts took back in the late 50s and early 60s. She’ll be the oldest person to fly into space. And with them will be Oliver Daemon, 18, the youngest person to fly in space.

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.

Addendum

A test Launch of the Blue Origin’s New Shepard rocket and Crew Capsule. Credit: Blue Origin.

07/19/2021 – Ephemeris – How does your telescope’s image orientation compare to how it looks to the naked-eye?

This is Ephemeris for Monday, July 19th. Today the Sun will be up for 15 hours and 6 minutes, setting at 9:22, and it will rise tomorrow at 6:16. The Moon, 2 days past first quarter, will set at 2:35 tomorrow morning.

When you look through a telescope at the Moon, how does it look compare to how it looks to the naked-eye? Yes, it’s bigger and probably brighter. But how did its orientation change? Astronomical telescopes generally give an upside-own image, that is rotated 180 degrees. Newtonian reflector telescopes, with their eyepiece near the top of the telescope, give such an image, as do refractor telescopes where the diagonal mirror near the eyepiece is not used. When such a mirror is used a right side up, but mirror image is the result. The mirror image results when an odd number of reflections occur in the light path. Binoculars use two or four reflections. Newtonian reflectors have two reflections. It can be confusing sometimes.

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.

Addendum