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08/01/2017 – Ephemeris – A look at the busy month of August in astronomy
Ephemeris for Tuesday, August 1st. The Sun rises at 6:29. It’ll be up for 14 hours and 38 minutes, setting at 9:07. The Moon, 2 days past first quarter, will set at 2:21 tomorrow morning.
Let’s look ahead at the month of August in the skies. Daylight hours will decrease from 14 hours and 38 minutes today 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 today to just over 53 degrees on the 31st. The Perseid meteor shower will reach its peak on the evening of the 12th. However the bright waning gibbous moon will rise just after 11:30 for a very short dark sky viewing period. The big event this month will be the total solar eclipse that will be visible from all 50 of the United States and total for a narrow strip of land stretching from Oregon to South Carolina. That will occur on the afternoon of Monday the 21st.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
August Evening Star Chart
Star Chart for August 2017 (10 p.m. August 15, 2017). Created using my LookingUp program. Click on image to enlarge.
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. (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 10 p.m. and 5 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.
August Morning Star Chart
Star Chart for August 2017 mornings based on 5 a.m. August 15th. 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
- Leaky Big Dipper drips on Leo
- Follow the arc of the handle of the Big Dipper to the star Arcturus,
- Then follow the Spike to Spica
- The Summer Triangle is in red
- PerR is the Perseid Meteor Shower radiant
Evening nautical twilight ends at 10:26 p.m. EDT on the 1st, decreasing to 9:30 p.m. EDT on the 31st.
Evening astronomical twilight ends at 11:15 p.m. EDT on the 1st, decreasing to 10:09 p.m. EDT on the 31st.
Morning astronomical twilight starts at 4:30 a.m. EDT on the 1st, and increasing to 5:24 a.m. EDT on the 31st.
Morning nautical twilight starts at 5:19 a.m. EDT on the 1st, and increasing to 6:03 a.m. EDT on the 31st.
NASA Calendar of Planetary Events
Date Time Event
Aug 01 Tu Venus: 38.4° W
02 We 1:55 pm Moon Apogee: 405000 km
03 Th 3:31 am Moon-Saturn: 3.8° S
04 Fr 2:17 pm Moon South Dec.: 19.4° S
07 Mo 2:11 pm Full Moon
07 Mo 2:22 pm Partial Lunar Eclipse (Not visible from here)
08 Tu 6:56 am Moon Descending Node
12 Sa 2:35 pm Perseid Shower: ZHR = 90
14 Mo 9:15 pm Last Quarter
16 We 2:39 am Moon-Aldebaran: 0.4° S
18 Fr 2:50 am Moon North Dec.: 19.4° N
18 Fr 9:14 am Moon Perigee: 366100 km
19 Sa 12:45 am Moon-Venus: 2.3° N
20 Su 3:15 am Moon-Beehive: 3.2° N
21 Mo 6:34 am Moon Ascending Node
21 Mo 2:26 pm Total Solar Eclipse
21 Mo 2:30 pm New Moon
25 Fr 9:00 am Moon-Jupiter: 3.7° S
26 Sa 4:32 pm Mercury Inferior Conj.
29 Tu 4:13 am First Quarter
30 We 7:25 am Moon Apogee: 404300 km
30 We 10:23 am Moon-Saturn: 3.9° S
31 Th 10:03 pm Moon South Dec.: 19.4° S
Sep 01 Fr Venus: 31.7° W
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.
August Rising and Setting Events
LU Ephemeris of Sky Events for Interlochen/TC August, 2017 Local time zone: EDT +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Tue 1| 06:29a 09:08p 14:38 | 10:23p 05:13a | Set 02:21a 72%| |Wed 2| 06:30a 09:06p 14:36 | 10:21p 05:15a | Set 03:00a 80%| |Thu 3| 06:31a 09:05p 14:34 | 10:20p 05:16a | Set 03:43a 87%| |Fri 4| 06:32a 09:04p 14:31 | 10:18p 05:18a | Set 04:32a 93%| |Sat 5| 06:33a 09:02p 14:29 | 10:16p 05:19a | Set 05:26a 97%| +------+-----------------------+----------------+-----------------------+ |Sun 6| 06:34a 09:01p 14:26 | 10:15p 05:21a | Set 06:24a 99%| |Mon 7| 06:36a 09:00p 14:23 | 10:13p 05:22a |Full Rise 09:01p 100%| |Tue 8| 06:37a 08:58p 14:21 | 10:11p 05:24a | Rise 09:35p 98%| |Wed 9| 06:38a 08:57p 14:18 | 10:09p 05:25a | Rise 10:06p 95%| |Thu 10| 06:39a 08:55p 14:16 | 10:07p 05:27a | Rise 10:36p 89%| |Fri 11| 06:40a 08:54p 14:13 | 10:06p 05:28a | Rise 11:06p 81%| |Sat 12| 06:41a 08:52p 14:10 | 10:04p 05:30a | Rise 11:36p 72%| +------+-----------------------+----------------+-----------------------+ |Sun 13| 06:43a 08:51p 14:08 | 10:02p 05:31a | Rise 12:09a 62%| |Mon 14| 06:44a 08:49p 14:05 | 10:00p 05:33a |L Qtr Rise 12:46a 51%| |Tue 15| 06:45a 08:48p 14:02 | 09:58p 05:34a | Rise 01:28a 39%| |Wed 16| 06:46a 08:46p 13:59 | 09:56p 05:36a | Rise 02:16a 28%| |Thu 17| 06:47a 08:44p 13:57 | 09:54p 05:37a | Rise 03:13a 18%| |Fri 18| 06:49a 08:43p 13:54 | 09:52p 05:39a | Rise 04:16a 10%| |Sat 19| 06:50a 08:41p 13:51 | 09:50p 05:40a | Rise 05:24a 4%| +------+-----------------------+----------------+-----------------------+ |Sun 20| 06:51a 08:39p 13:48 | 09:48p 05:42a | Rise 06:35a 1%| |Mon 21| 06:52a 08:38p 13:45 | 09:47p 05:43a |New Set 08:44p 0%| |Tue 22| 06:53a 08:36p 13:42 | 09:45p 05:44a | Set 09:18p 2%| |Wed 23| 06:54a 08:34p 13:39 | 09:43p 05:46a | Set 09:49p 6%| |Thu 24| 06:56a 08:33p 13:37 | 09:41p 05:47a | Set 10:18p 12%| |Fri 25| 06:57a 08:31p 13:34 | 09:39p 05:49a | Set 10:46p 20%| |Sat 26| 06:58a 08:29p 13:31 | 09:37p 05:50a | Set 11:15p 28%| +------+-----------------------+----------------+-----------------------+ |Sun 27| 06:59a 08:27p 13:28 | 09:35p 05:52a | Set 11:46p 37%| |Mon 28| 07:00a 08:26p 13:25 | 09:33p 05:53a | Set 12:19a 47%| |Tue 29| 07:01a 08:24p 13:22 | 09:31p 05:54a |F Qtr Set 12:56a 56%| |Wed 30| 07:03a 08:22p 13:19 | 09:29p 05:56a | Set 01:38a 65%| |Thu 31| 07:04a 08:20p 13:16 | 09:27p 05:57a | Set 02:24a 74%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunset and sunrise
08/11/2016 – Ephemeris – The Perseid meteors will peak tonight!
Ephemeris for Thursday, August 11th. The Sun rises at 6:41. It’ll be up for 14 hours and 12 minutes, setting at 8:53. The Moon, 1 day past first quarter, will set at 1:31 tomorrow morning.
This evening and tomorrow morning we should see the peak of the Perseid Meteor Shower. There is the expected broad peak of the shower which for us is after sunrise. However the meteoroid stream isn’t monolithic. Each pass of the comet in the inner solar system superimposes its debris on the general stream, so we will have increased activity all night tonight and even into Saturday morning. In general Perseid meteors will be seen to come from the northeast. The evening view will be hampered by the Moon which will drown out the dimmer meteors. The best time to view is after the Moon sets at 1:31 tomorrow morning until morning twilight becomes noticeable around 5 a.m. when over 100 meteors might be spotted an hour.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Perseid meteor shower radiant a about 2 a,m, during the period of the shower. Created using my LookingUp program.
Here are some meteors seen in the 2007 Perseid meteor shower taken by Scott Anttila. The image is centered on Cassiopeia. The radiant is low and a bit left of center in the image. The Double Cluster is seen below center and the Great Andromeda Galaxy is seen on the right just above center.
My best Perseid photo. From the 70’s.
08/10/2016 – Ephemeris – The planets tonight
Ephemeris for Wednesday, August 10th. The Sun rises at 6:39. It’ll be up for 14 hours and 15 minutes, setting at 8:55. The Moon, at first quarter today, will set at 12:55 tomorrow morning.
Today we turn from the small meteoroids that orbit the Sun that are producing the Perseid Meteor Shower to the larger members of the solar family, namely the bright planets. Venus and Mercury are very low in the west-northwest and will set at 9:44 and 9:50 p.m. respectively. Jupiter is in the west in the evening. It will set at 10:19 p.m. Mars, Saturn and the star Antares start the evening in the south-southwestern sky as a tightening triangle, moving to the southwest during the evening. Antares, whose name means Rival of Mars is below Saturn with brighter Mars to the right. The Red Planet is back in Scorpius. It will set at 12:46 a.m. Mars is moving rapidly to the east against the stars. Saturn is spectacular in telescopes, with its rings. Saturn will set at 1:34 a.m.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus, Mercury and Jupiter at 9:25 p.m. (30 minutes after sunset), August 10, 2016. Created using Stellarium.
The planets, Moon and constellations at 10 p.m., August 10, 2016. Created using Stellarium.
The Moon as it might appear in binoculars tonight, August 10, 2016 at 10 p.m. Created using Stellarium.
Saturn and its moons at 10 p.m. August 10, 2016. Created using Cartes du Ciel (Sky Charts).
Planets at sunset and sunrise of a single night starting with sunset on the right on August 10, 2016. The night ends on the left with sunrise on August 11. Actually all the naked eye planets are in the evening sky. Also shown is the Perseid meteor shower radiant. If you are using Firefox right-click on the image and select View Image to enlarge the image. That goes for all the large images. Created using my LookingUp program.
Also shown is the Perseid meteor shower radiant.
08/09/2016 – Ephemeris – A look at the Perseids progenitor
Ephemeris for Tuesday, August 9th. The Sun rises at 6:38. It’ll be up for 14 hours and 18 minutes, setting at 8:56. The Moon, 1 day before first quarter, will set at 12:23 tomorrow morning.
Comet Swift-Tuttle is the comet responsible for the Perseid Meteor Shower which is now ramping up and will reach its peak Thursday night and Friday morning. The comet was independently discovered by Swift and Tuttle in the summer of 1862. Based on three months of observations it was predicted to return after 120 years in 1982. After it failed to appear more work was done to refine the orbit, and to check for past appearances of the comet. Sure enough comets appearing to fit the orbit were found in 188 CE and 69 BCE, so a new prediction for the comet to reappear was made for 1992 by the late Dr. Brian Marsden of the Smithsonian Astrophysical Observatory. His revised prediction was only off by 17 days.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above (North). Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).
Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above. That’s why the radiant is so far north. See yesterday’s post for the radiant point. Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL).
These were generated a couple of years ago. However the comet won’t be back until 2122 give or take.
08/08/2016 – Ephemeris – This week the Perseid meteors ramp up
Ephemeris for Monday, August 8th. The Sun rises at 6:37. It’ll be up for 14 hours and 20 minutes, setting at 8:58. The Moon, 2 days before first quarter, will set at 11:54 this evening.
The Perseid meteor shower will reach its peak for this year between 9 and 11:30 a.m. Friday morning, the 12th. There is some expectation that there will be an enhancement of meteor numbers on Thursday evening before midnight. Our problem is that the Moon will be out and bright Thursday evening and will set at 1:31 a.m. Friday morning. The bright Moon doesn’t preclude seeing meteors, but only the brightest ones will be visible. Also we have been seeing precursor meteors for the last three weeks, slowly ramping up to Friday morning’s peak. You’ll see them every night this week. The meteors are caused by the debris from Comet Swift-Tuttle whose 130 year orbit of the Sun over the millennia, has strewn meteoroids along its orbit.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Perseid meteor shower radiant is circumpolar for northern Michigan, so the meteors will be visible all night.
Perseid radiant at 10:30 p.m.
Perseid Meteor Shower radiant after midnight
07/28/2016 – Ephemeris – Two upcoming meteor showers plus an occultation tomorrow morning
Ephemeris for Thursday, July 28th. The Sun rises at 6:25. It’ll be up for 14 hours and 47 minutes, setting at 9:12. The Moon, 2 days past last quarter, will rise at 2:31 tomorrow morning.
We have a couple of meteor showers of note coming up. The first is the Southern Delta Aquariids which will peak on the 30th. The radiant point for these meteors will rise around midnight in the southeast. Their numbers and their brightness are not very great. The Perseid meteor shower peak will have interference from the waxing gibbous moon drowning out all but the brightest meteors on the evening of August 11 and morning of he 12th. However the Perseids have a long run up to their peak, so their numbers will grow after the moon sets. The Perseid radiant is circumpolar for Northern Michigan, meaning it never sets, so some Perseid meteors can always be seen at night. Their radiant will be low in the northeastern sky in the evening and much higher in the northeast just before dawn.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
Approximate Radiant of the South Delta Aquariid meteor shower. The radiant does move over the several weeks of the shower to the east. Created using my LookingUp program.
Perseid Meteor Shower radiant after midnight. Created using my LookingUp program.
Update: Occultation of Aldebaran tomorrow morning
The area where the occultation of Aldebaran will be visible. The area bordered by the white lines is where the occultation will occur with the Sun below the horizon. Credit IOTA’s Occult 4 program.
There will be an occultation of Aldebaran by the Moon centered on 11:16 UT (7:16 a.m. EDT) July 29, 2016. Our area (Michigan) cannot see the event, being too far north. It will be visible south of a line containing the state of Maine down through Texas. Universe Today has information on grazing occultation possibilities: http://www.universetoday.com/129841/spectacular-aldebaran-graze-july-29/
08/12/2015 – Ephemeris – One ringed planet and a sky full of meteors
Ephemeris for Wednesday, August 12th. The Sun rises at 6:41. It’ll be up for 14 hours and 12 minutes, setting at 8:53. The Moon, 2 days before new, will rise at 5:49 tomorrow morning.
Lets take a look for the bright planets for this week. Our brightest evening planets Venus and Jupiter are leaving the evening sky in the west. Venus is 3 days from inferior conjunction with the Sun. Saturn is in the south-southwest in the evening twilight. It can be spotted just to the right of the constellation of Scorpius the scorpion and its bright red star Antares below and right of it. Even small telescopes can see Saturn’s rings. The Perseid meteor shower will reach its peak overnight tonight. Your back yard is a fine spot to view the meteors, or for dark skies, I’ll be leading an all night meteor watch at the Sleeping Bear Dunes National Lakeshore’s Dune Climb if it’s clear. I’ll be there by 9 p.m. and it will be dark enough by 10:30.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Saturn and the summer Zodiacal constellations in the south at 10 p.m. August 12, 2015. Created using Stellarium.
Saturn through a telescope at 10 p.m. on August 12, 2015. Created using Stellarium.
Next week Wednesday we will also turn to the morning sky looking for Mars and awaiting Venus’ grand entrance into the dawn skies.
All-sky meteor charts from yesterday’s post
“PerR” is the Perseid radiant.
11 p.m. August 12, 2015. Created using Bob Moler’s LookingUp program for Windows.
2 a.m. August 13, 2015. Previewing autumn stars. Created using Bob Moler’s LookingUp program for Windows.
5 a.m. August 13, 2015. Good morning Orion! Created using Bob Moler’s LookingUp program for Windows.
08/11/2015 – Ephemeris – Perseid meteor shower is tomorrow night
Ephemeris for Tuesday, August 11th. The Sun rises at 6:40. It’ll be up for 14 hours and 14 minutes, setting at 8:55. The Moon, 3 days before new, will rise at 4:51 tomorrow morning.
The Perseid meteor shower is growing in numbers of meteors seen per hour. The expected peak is Thursday morning about a quarter after 2. However the peak time is only really known statistically after the event. The point in the sky from which the meteors or shooting stars seem to come from is called the radiant and it is near the constellation of Perseus. The meteors will appear all night from dusk to dawn. The peak number of meteors can be up to 90 an hour. No telescope is needed. Just lie down on a blanket and look up. The darker your sky the better. One of the darkest skies around is at the Sleeping Bear Dunes National Lakeshore. I will be leading an all night meteor shower watch at the Dune Climb Wednesday night til dawn if it’s clear.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here are some meteors seen in the 2007 Perseid meteor shower taken by Scott Anttila. The image is centered on Cassiopeia. The radiant is low and a bit left of center in the image. The Double Cluster is seen below center and the Great Andromeda Galaxy is seen on the right above center. Click on the image to enlarge.
Position of the Perseid radiant and stars in all-sky plots for 3 times during the night: 11 p.m., 2 a.m., & 5 a.m.
11 p.m. August 12, 2015. Created using Bob Moler’s LookingUp program for Windows.
2 a.m. August 13, 2015. Created using Bob Moler’s LookingUp program for Windows.
5 a.m. August 13, 2015. Created using Bob Moler’s LookingUp program for Windows.
08/10/2015 -Ephemeris – The Tears of St. Lawrence
Ephemeris for Monday, August 10th. The Sun rises at 6:39. It’ll be up for 14 hours and 17 minutes, setting at 8:56. The Moon, half way from last quarter to new, will rise at 3:55 tomorrow morning.
Today is the Catholic Church’s feast of Saint Lawrence a deacon, who was martyred around 258. I make reference to this because of the Perseid meteor shower which will reach peak early Thursday morning. It is also known as the Tears of St Lawrence or St Lawrence’s Fiery Tears because the meteor shower comes near the date of the feast. We know these meteors as the Perseids because the appear to come from just off the constellation of Perseus the hero in our northern sky. Small bits of rocky material are the meteoroids that have been shed from Comet Swift-Tuttle on its previous passes near the sun strike the Earth’s atmosphere. Since the comet’s orbit nearly crosses the Earth’s orbit we pass through this ring of debris every year.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Perseid meteor shower radiant a about 2 a,m, during the period of the shower. Created using my LookingUp program.
My best Perseid photo. From the 70’s.
08/03/2015 – Ephemeris – The Perseids are coming!
Ephemeris for Monday, August 3rd. The Sun rises at 6:30. It’ll be up for 14 hours and 35 minutes, setting at 9:06. The Moon, half way from full to last quarter, will rise at 10:58 this evening.
After the Moon sets in the evening and morning hours for the next week and a half the numbers of meteors visible will increase each night. These are members of the Perseid meteor shower of August. The peak this year is expected to be during the 2 o’clock hour on the morning of the 13th. These meteors are the result of debris left in the orbit of Comet Swift-Tuttle shed by innumerable visits to the inner solar system. Every year at this time the Earth passes through this trail of debris which intersects its orbit giving rise to the meteor shower. We call them the Perseids, because the appear to come from the direction of the constellation Perseus the hero, which is first seen in the early evening low in the northeast.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Perseid radiant at 10:30 p.m.
Orbit of Comet 109P/Swift-Tuttle. Blue line is the comet’s orbit, coming from above (North). Credit NASA / JPL / Applet by Osamu Ajiki (AstroArts), and further modified by Ron Baalke (JPL)
The distances in the lower left corner are the comet’s current distances from the Earth and Sun. AU is astronomical units the mean distance between the Earth and Sun. The comet’s last pass through the inner solar system was in 1992. Swift-Tuttle is now out just past the current position of the dwarf planet Pluto. Link to the animation from which the above image was taken and other information on Comet Swift-Tuttle go to http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=109P;cad=1
Bob Moler's Ephemeris Blog 