Archive
03/02/2017 – Ephemeris – Saturday night’s occultation of the bright star Aldebaran
Note: this program is for a very specific location in the northern lower peninsula of Michigan. The occultation of Aldebaran is visible from most of the United States except Alaska and Central America. For predictions for your locations you can use a planetarium type program like Stellarium, Cartes du Ciel (Sky Charts), which can be downloaded free from the right column on this blog page, or the commercial planetarium program of your choice. Make sure the program is zoomed in so the Moon is actual size, and set for your location, and play around with the time.
Path of the occultation of Aldebaran for March 4-5, 2017. Note where the top edge of the path goes. Right through northern Michigan.
On to the program:
Ephemeris for Thursday, March 2nd. The Sun will rise at 7:17. It’ll be up for 11 hours and 14 minutes, setting at 6:32. The Moon, 3 days before first quarter, will set at 11:26 this evening.
Saturday night just after 11 p.m. the upper right edge of the Moon will just cover the bright star Aldebaran, the angry red eye of Taurus the bull. That is for some of us. For those of us south of a line from Leland to just south of Mancelona and off across the state the Moon will occult or hide the star. For those north of that line Aldebaran will just miss the Moon. Start looking at 11 p.m. or so. The center of the occultation as it I called is about 11:13 p.m. The farther south of that line you are the longer the occultation will last. At 11 p.m. the star will be just off the upper right edge of the Moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
The north limit of the occultation zone as it passes through the Grand Traverse Region. Locations north of the green line will not see an occultation, Locations south of that line will see the occultation. Map credit Google Earth.
The file to load for this occultation map overlay is: http://ephemeris.bjmoler.org/ZC692-2017-Mar-5.kmz.
The point of the mid occultation from the NMC Observatory. Note that in reality Aldebaran would be completely covered by the Moon. This is the Moon and Aldebaran as they would be seen in the west at that time. Created using Cartes du Ciel (Sky Charts).
The occultation of Aldebaran as seen from three sample locations in the IPR listening area. Credit IOTA’s Occult4 program. The Moon is shown in equatorial orientation.
Here’s the legend for the labels:
# H M S (Mag)
#: 1 First contact, Aldebaran disappears
2 Middle of the occultation
3 Last contact, Aldebaran reappears
H: hour UT, 4 = 11 p.m. EST
M: Minute
S: Second
Mag: Magnitude of the star, 0.9 (First magnitude star)
An article I wrote about this occultation in the March 2017 issue of the Grand Traverse Astronomical Society newsletter The Stellar Sentinel:
The Grazing Occultation of Aldebaran, March 4th
Late Saturday night March 4th the Moon will pass in front of, or not the bright star Aldebaran. The “or not” depends on where you are.
The event is called an occultation. The word comes from occult, which, despite its baggage, simply means hidden. When one celestial body moves in front of another and completely covers it an occultation occurs. In actuality a total solar eclipse is an occultation. However a lunar eclipse is still an eclipse as we see it, but an occultation as the Sun sees it.
Above there’s a map of the Leelanau and Old Mission peninsulas and a bit of the Lower Peninsula of Michigan with a line drawn across it from north of Leland to just south of Mancelona. That is the calculated northern limit of the occultation. Observers within a mile of so of that line could see Aldebaran winking in and out as it’s light encounters mountains and passes through valleys at the northern limb of the Moon.
Even though we’ve landed humans on the Moon and have mapping satellites orbiting it, there is still a need to add more data to the accumulated knowledge we have of the surface and position of the Moon. Observers in a coordinated effort can be set up perpendicular to the graze line and using coordinated time signals produce a map of the edge of the Moon.
Plot of the results of a grazing occultation of Delta Cancri on May 9-10, 1981. Each horizontal line is one observer’s timings. From “An Introduction to Grazing Occultations” at http://www.lunar-occultations.com/iota/Graze.htm.
02/28/2017 – Ephemeris – Previewing the skies of March 2017
Ephemeris for Fat Tuesday, February 28th. The Sun will rise at 7:21. It’ll be up for 11 hours and 8 minutes, setting at 6:29. The Moon, 2 days past new, will set at 9:03 this evening.
Let’s preview the month of March which begins tomorrow. In March the increase in daylight hours is at its greatest, with Spring 3 weeks away. Daylight hours will increase from 11 hours and 11 minutes tomorrow to 12 hours and 44 minutes on the 31st. Along with that the altitude of the sun at local noon will increase from 38 degrees today to 49 ½ degrees at month’s end. The big astronomical event of this month will be a near grazing occultation of the bright star Aldebaran by the Moon. Aldebaran is the bright star in the face of Taurus the bull. This will occur just after 11 p.m. Saturday night the 4th. The southern half of the IPR listening area will be able to see it. See bobmoler.wordpress.com for more information.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
March Star Charts
Evening
Star Chart for March 2017. Created using my LookingUp program. Click on image to enlarge.
Morning
Star Chart for March 2017 mornings. Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 10 p.m. EDT, and again at 6 a.m. Those are chart times. Note, 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 1:45 or 0:45 earlier than the current time if you were near your time meridian.
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
- Straighten to a spike to Spica
- The Summer Triangle is shown in red
Evening nautical twilight ends at 7:32 p.m. EST on the 1st, increasing to 9:16 p.m. EDT on the 31st.
Evening astronomical twilight ends at 8:06 p.m. EST on the 1st, increasing to 9:53 p.m. EDT on the 31st.
Morning astronomical twilight starts at 5:43 a.m. EST on the 1st, and increasing to 5:48 a.m. EDT on the 31st.
Morning nautical twilight starts at 6:17 a.m. EST on the 1st, and Increasing to 6:25 a.m. EDT on the 31st.
NASA Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Time and follow the time change dates.
Date Time Event Mar 01 We Venus: 32.5° E 01 We 1:58 am Moon-Mars: 4.4° N 01 We 9:22 pm Neptune Conjunction 03 Fr 2:24 am Moon Perigee: 369100 km 04 Sa 9:38 pm Moon-Aldebaran: 0.2° S Occultation! 05 Su 6:32 am First Quarter 06 Mo 7:08 pm Mercury Superior Conjunction with the Sun 06 Mo 7:43 pm Moon North Dec.: 18.9° N 10 Fr 5:20 pm Moon-Regulus: 0.9° N 10 Fr 11:17 pm Moon Ascending Node 12 Su 2:00 am Daylight Saving Time starts (Spring Forward) 12 Su 10:54 am Full Moon 14 Tu 4:04 pm Moon-Jupiter: 2.7° S 18 Sa 1:25 pm Moon Apogee: 404700 km 20 Mo 6:29 am Vernal Equinox. Spring starts 20 Mo 6:49 am Moon-Saturn: 3.8° S 20 Mo 11:58 am Last Quarter 21 Tu 1:22 am Moon South Dec.: 18.9° S 25 Sa 6:31 am Venus Inferior Conjunction with the Sun 25 Sa 11:41 am Moon Descending Node 27 Mo 10:57 pm New Moon 30 Th 8:39 am Moon Perigee: 363900 km Apr 01 Sa Venus: 13.4° W
March 2017 Calendar
LU Ephemeris of Sky Events for Interlochen/TC March, 2017 Local time zone: EST +-----------------------------------------------------------------------+ | DATE | SUN SUN DAYLIGHT| TWILIGHT* |MOON RISE OR ILLUM | | | RISE SET HOURS | END START |PHASE SET** TIME FRACTN| +=======================================================================+ |Wed 1| 07:19a 06:30p 11:11 | 07:34p 06:16a | Set 10:15p 14%| |Thu 2| 07:18a 06:32p 11:14 | 07:35p 06:15a | Set 11:26p 23%| |Fri 3| 07:16a 06:33p 11:17 | 07:36p 06:13a | Set 12:37a 33%| |Sat 4| 07:14a 06:34p 11:20 | 07:37p 06:11a | Set 01:45a 44%| +------+-----------------------+----------------+-----------------------+ |Sun 5| 07:12a 06:36p 11:23 | 07:39p 06:09a |F Qtr Set 02:50a 56%| |Mon 6| 07:11a 06:37p 11:26 | 07:40p 06:08a | Set 03:48a 67%| |Tue 7| 07:09a 06:38p 11:29 | 07:41p 06:06a | Set 04:40a 77%| |Wed 8| 07:07a 06:40p 11:32 | 07:43p 06:04a | Set 05:25a 86%| |Thu 9| 07:05a 06:41p 11:35 | 07:44p 06:02a | Set 06:04a 92%| |Fri 10| 07:03a 06:42p 11:38 | 07:45p 06:00a | Set 06:38a 97%| |Sat 11| 07:02a 06:44p 11:42 | 07:47p 05:59a | Set 07:09a 100%| +------+-----------------------+----------------+-----------------------+ | EDT | Time Change | | | |Sun 12| 08:00a 07:45p 11:45 | 08:48p 06:57a |Full Rise 08:00p 100%| |Mon 13| 07:58a 07:46p 11:48 | 08:49p 06:55a | Rise 09:03p 98%| |Tue 14| 07:56a 07:47p 11:51 | 08:51p 06:53a | Rise 10:05p 94%| |Wed 15| 07:54a 07:49p 11:54 | 08:52p 06:51a | Rise 11:05p 89%| |Thu 16| 07:52a 07:50p 11:57 | 08:53p 06:49a | Rise 12:04a 82%| |Fri 17| 07:51a 07:51p 12:00 | 08:55p 06:47a | Rise 01:01a 74%| |Sat 18| 07:49a 07:53p 12:03 | 08:56p 06:46a | Rise 01:57a 66%| +------+-----------------------+----------------+-----------------------+ |Sun 19| 07:47a 07:54p 12:07 | 08:57p 06:44a | Rise 02:50a 56%| |Mon 20| 07:45a 07:55p 12:10 | 08:59p 06:42a |L Qtr Rise 03:40a 47%| |Tue 21| 07:43a 07:56p 12:13 | 09:00p 06:40a | Rise 04:27a 37%| |Wed 22| 07:41a 07:58p 12:16 | 09:01p 06:38a | Rise 05:09a 28%| |Thu 23| 07:39a 07:59p 12:19 | 09:03p 06:36a | Rise 05:48a 19%| |Fri 24| 07:38a 08:00p 12:22 | 09:04p 06:34a | Rise 06:24a 12%| |Sat 25| 07:36a 08:01p 12:25 | 09:05p 06:32a | Rise 06:58a 6%| +------+-----------------------+----------------+-----------------------+ |Sun 26| 07:34a 08:03p 12:28 | 09:07p 06:30a | Rise 07:31a 2%| |Mon 27| 07:32a 08:04p 12:32 | 09:08p 06:28a |New Set 07:43p 0%| |Tue 28| 07:30a 08:05p 12:35 | 09:10p 06:26a | Set 08:56p 1%| |Wed 29| 07:28a 08:06p 12:38 | 09:11p 06:24a | Set 10:10p 5%| |Thu 30| 07:26a 08:08p 12:41 | 09:12p 06:22a | Set 11:24p 11%| |Fri 31| 07:25a 08:09p 12:44 | 09:14p 06:20a | Set 12:36a 20%| +-----------------------------------------------------------------------+ * Nautical Twilight ** Moonrise or moonset, whichever occurs between sunrise and sunset
Grazing Occultation of Aldebaran March 4 or 5, 2017 (Depending on your location)
Path of the occultation of Aldebaran for March 4-5, 2017. Note where the top edge of the path goes. Right through northern Michigan.
Here’s the line where the limit of the occultation passes in northwestern lower Michigan. Occult4 kml file plotted on Google Earth.
The central time of the occultation is 11:13 p.m. Start viewing the Moon before 11 p.m. The farther south one is of the line the earlier the occultation starts and the longer it lasts. I’ll have lots more information in Thursday’s post.
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/
05/13/2016 – Ephemeris – GTAS Astronomy Day tomorrow
Ephemeris for Friday, May 13th. Today the Sun will be up for 14 hours and 46 minutes, setting at 9:02. The Moon, at first quarter today, will set at 2:59 tomorrow morning. Tomorrow the Sun will rise at 6:15.
The Grand Traverse Astronomical Society will host a public viewing night for Astronomy Day tomorrow night, that’s Saturday the 14th, starting at 9 p.m. It will be at Northwestern Michigan College’s Joseph Rogers Observatory. If its clear the slightly gibbous moon will be featured along with Jupiter, Mars and the ringed planet Saturn and other wonders of the spring sky. The observatory is located south of Traverse City, on Birmley Road between Garfield and Keystone roads. For the society these, twice monthly star parties at the observatory and sidewalk astronomy outings by members, to the Sleeping Bear Dunes National Lakeshore and other locations are what they do.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Other thoughts
I was checking out the Solar and Heliospheric Observatory (SOHO) LASCO C3 animation and Venus is making an entrance from the right as it heads for superior conjunction on June 6. June 6? Hmm. Wasn’t that last transit or Venus on June 5th 2012. We and Venus should be near the line of nodes again, where the planes of our respective orbits cross. I cranked up Stellarium, and sure enough the Sun will occult Venus that day… Not that we could see it.
01/01/2016 – Ephemeris – Happy New Year – It’s a busy few days to start off the year
Happy New Year. This is Bob Moler with Ephemeris for New Years Day, Friday, January 1st, 2016. The Sun will rise at 8:20. It’ll be up for 8 hours and 52 minutes, setting at 5:12. The Moon, 1 day before last quarter, will rise at 12:54 tomorrow morning.
It’s always a busy time, astronomically speaking, around the start of the year. This year even more so. Comet Catalina is found near the bright star Arcturus now, which is a good way to find it in binoculars. Tomorrow at 7:59 p.m. (1:59 UT 3rd) the Earth will reach perihelion, the closest point in its orbit to the Sun at about 91.4 million miles (0.9833 AU). It doesn’t add much to the heat we get from the Sun, but it does make winter a couple of days shorter than summer. Monday at 3 a.m. will see the peak of the Quadrantid meteor shower. Unfortunately that’s about the time the Moon will rise. The radiant is north of the handle of the Big Dipper. Good news: tomorrow is the latest sunrise, it should be rising earlier until June.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
January Star Chart
Star Chart for January 2016. Created using my LookingUp program. To enlarge in Firefox Right-click on image then click View Image.
The planets and stars are plotted for the 15th at 9 p.m. EST. That is chart time. Note, Traverse City is located 45 minutes behind our time meridian. To duplicate the star positions on a planisphere you may have to set it to 45 minutes earlier than the current time.
Evening astronomical twilight ends at 6:22 p.m. EST on January 1st, increasing to 6:55 p.m. EST on the 31st.
Morning astronomical twilight starts at 7:09 a.m. EST on January 1st, and decreasing to 6:57 a.m. EST on the 31st.
Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.
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.
- QuadR is the Quadrantid meteor shower radiant
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Time. Some additions made to aid clarity.
Date Local Event Time EST Jan 01 Fr Venus: 37.9° W 02 Sa 12:30 a.m. Last Quarter 02 Sa 6:53 a.m. Moon Apogee: 404300 km 02 Sa 7:59 p.m. Perihelion: 0.9833 AU 03 Su 1:45 p.m. Moon-Mars: 1.6° S 04 Mo 3:01 a.m. Quadrantid Shower: ZHR = 120 06 We 6:57 p.m. Moon-Venus: 3.3° S 06 We 11:57 p.m. Moon-Saturn: 3.6° S 07 Th 6:32 a.m. Venus-Antares: 6.4° N 08 Fr 12:56 p.m. Moon South Dec.: 18.4° S 09 Sa 2:42 a.m. Venus-Saturn: 0.1° N 09 Sa 8:30 p.m. New Moon 14 Th 9:02 a.m. Mercury Inferior Conj. 14 Th 10:48 a.m. Moon Descending Node 14 Th 9:10 p.m. Moon Perigee: 369600 km 16 Sa 6:26 p.m. First Quarter 19 Tu 9:16 p.m. Moon-Aldebaran: 0.5° S (Occultation*) 21 Th 11:41 a.m. Moon North Dec.: 18.4° N 23 Sa 8:46 p.m. Full Moon 26 Tu 12:10 a.m. Moon-Regulus: 2.8° N 27 We 6:58 p.m. Moon Ascending Node 27 We 8:14 p.m. Moon-Jupiter: 1.6° N 30 Sa 4:10 a.m. Moon Apogee: 404600 km 31 Su 10:28 p.m. Last Quarter Feb 01 Mo Venus: 31.4° W
* Occultation of Aldebaran For the Grand Traverse Area ± 1-2 minutes:
Disappearance 9:06 p.m. Reappearance 10:25 p.m. I’ll have more information on the 19th.
Occultation Map
Occultation visibility map for January 20, 2016 (UT). Credit IOTA/Occult4 program.
Estimating occultation timings for your location
I used Cartes du Ciel the free software that I have a link to on the right. Make sure that the program is set for topocentric positions under Setup/Solar System. And you have entered your position under Setup/Observatory. You can find your location in Google Earth, or your GPS device or smart phone.
You can also use Stellarium. Just make sure the Moon is normal sized.
In both programs you can lock the Moon or Aldebaran in the center of the screen Pick a time in advance of the occultation and using the set time window walk the star towards the Moon, mark the time. Then walk the star out from the Moon and record the reappearance time. That’s it.
This should work with other planetarium programs too.
For better accuracy go to the International Occultation Timing Association (IOTA) website. Download and install their Occult4 program for Windows computers. Follow the instructions. When I ran the program for my location, the location I use for Interlochen/Traverse City (Since I live approximately half-way between the two). I got results within a half-minute of the IOTA Occult4 program results. So the approximation method using these planetarium programs is valid.
Comet C/2013 US10 (Catalina)
The track of Comet C/2013 US10 (Catalina) for January 2016. Created using Cartes du Ciel (Sky Charts).
The comet is roughly one magnitude fainter than given. Comet is plotted every day at 4 a.m. EST (9 hr UT) with the date and magnitude labeled every 5th day. According to the brightness graph the comet began to under perform in brightness back in September, however, according to a new brightness formula the comet may increase in brightness by a magnitude by late February when it will be well placed for viewing all night. To monitor the brightness reports from observers go to http://www.aerith.net/comet/catalog/2013US10/2013US10.html.
xxxvvvvv
12/07/2015 – Ephemeris – Today the Moon will pass in front of the planet Venus
Ephemeris for Monday, December 7th. The Sun will rise at 8:06. It’ll be up for 8 hours and 56 minutes, setting at 5:02. The Moon, half way from last quarter to new, will rise at 5:04 tomorrow morning.
The Moon will pass in front of Venus between about 12:20 p.m. and 1:27 p.m. for the Interlochen, Traverse City Area. Times will vary as much as 5 minutes over the IPR listening area. Some sort of telescopic aid is needed to see Venus and the crescent Moon in daylight. The crescent Moon is quite faint, though Venus should be easier to spot because it’s brighter. I have a special post on my blog dated Saturday December 5th.. It’s titled Venus Occultation December 7, 2015 from Northern Michigan with all the details. My blog is bobmoler.wordpress.com, or do an Internet search for Bob Moler, That’s Moler spelled M-O-L-E-R, no extra letters. And hope for clear skies.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation of the occultation. Created using Cartes du Ciel (Sky Charts) and GIMP.
Venus Occultation December 7, 2015 from Northern Michigan
What is an occultation? An occultation is when one nearer celestial body covers or hides another, more distant body. The word occultation comes from occult which simply means hidden. No black magic is involved.
The occultation of Venus will occur on December 7, from 12:21 p.m. to 1:27 p.m. for the Grand Traverse Area, give or take a few minutes either way. The exact time depends on your location. This event would be a great sight if it occurred in the early morning skies before sunrise. Unfortunately it’s centered on 1 p.m. Venus and the Moon are visible in the daytime with a telescope and even binoculars, but are difficult to find. The Moon and Venus do make a beautiful sight in the morning in the 5 to 7 a.m. hours.
Disappearance of Venus at 12:20 p.m. Created using Cartes du Ciel (Sky Charts).
The trick to viewing this event is even finding the Moon or Venus. One could set up a telescope with tracking ability to track Venus throughout the morning. Unless you have a telescope Go To mount and can track the Moon, track Venus instead. The Moon moves about its own diameter with respect to the stars in an hour, so it will have to be constantly adjusted to keep pointed at the Moon. Actually Venus has a higher surface brightness than the Moon, so it should be easier to track, especially if the sky is hazy and the Moon isn’t visible.
Disappearance of Venus at 1:27 p.m. Created using Cartes du Ciel (Sky Charts).
Unlike a stellar occultation Venus will disappear over several seconds. A telescope capable to seeing Venus’ gibbous phase will see the bright edge of the Moon actually pass in front it. Venus will emerge from the Moon’s dark side which will be invisible. So Venus will slowly reappear next to the crescent Moon. Hoping for clear skies, and good luck.
If you are not located near Traverse City, you can use my technique to estimate the occultation times. I used Cartes du Ciel the free software found on the Internet at http://www.ap-i.net/skychart/en/start. Make sure that the program is set for topocentric positions under Setup/Solar System. And you have entered your position under Setup/Observatory. You can find your location in Google Earth.
You can also use Stellarium (http://stellarium.org). Just make sure the Moon is normal sized.
In both programs you can lock the Moon or Aldebaran in the center of the screen Pick a time in advance of the occultation and using the set time window walk the star towards the Moon, mark the time. Then walk the star out from the Moon and record the reappearance time. That’s it.
This should work with other planetarium programs too.
Animation of the occultation. Created using Cartes du Ciel (Sky Charts) and GIMP.
For better accuracy go to the International Occultation Timing Association (IOTA) website. Download and install their Occult4 program for Windows computers. Follow the instructions. When I ran the program for my location, the location I use for Interlochen/Traverse City (Since I live approximately half-way between the two). I got results within a half-minute of the IOTA Occult4 program results. So the approximation method using planetarium programs is valid.
Sun and Moon’s positions at the start of the occultation from northern Michigan. Note the Moon and Venus will be invisible to the naked eye. Created using Stellarium.
Sun and Moon’s positions at the end of the occultation from northern Michigan. Note the Moon and Venus will be invisible to the naked eye. Created using Stellarium.
When I made up the above images I really thought there would be snow on the ground by now. But what little we had has come and gone.
Occultation of Venus Visibility Map for North America. Credit: Astronomical Almanac Online -U.S. Nautical Almanac Office, United States Naval Observatory (USNO), in the United States and Her Majesty’s Nautical Almanac Office (HMNAO), United Kingdom Hydrographic Office (UKHO), in the United Kingdom.
12/01/2015 – Ephemeris – Previewing December skies
Ephemeris for Tuesday, December 1st. The Sun will rise at 7:59. It’ll be up for 9 hours and 4 minutes, setting at 5:03. The Moon, 2 days before last quarter, will rise at 11:13 this evening.
December is the month with the shortest daylight hours. Winter will officially arrive at the winter solstice on the 21st at 11:48 p.m. There will be little movement in the sunset times: In the Traverse City/Interlochen area this will be from 5:03 tonight, down to 5:02 and then advancing to 5:11 at the end of the month. There is more movement in the sunrise times which will advance from 7:59 today to 8:20 on the 31st. There is also little movement of daylight hours. The noontime sun will hang around 22 to 23 degrees above the southern horizon all month. We have some great events this month, from an occultation of Venus by the moon on the 7th, to the Geminid meteors on the 14th and Comet Catalina will be seen in binoculars on mornings all this month.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
Star Chart for December 2015. Created using my LookingUp program. Click on image to enlarge.
The planets and stars are plotted for the 15th at 9 p.m. EST. That is chart time. Note, Traverse City is located 45 minutes behind our time meridian. To duplicate the star positions on a planisphere you may have to set it to 45 minutes earlier than the current time.
Evening astronomical twilight ends at 6:48 p.m. EST on December 1st, decreasing a minute 9 days later before increasing to 6:57 p.m. EST on the 31st.
Morning astronomical twilight starts at 6:15 a.m. EST on December 1st, and increasing to 6:34 a.m. EST on the 31st.
Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.
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.
- The Summer Triangle is still up and is shown in red.
- GemR is the Geminid meteor shower radiant
Calendar of Planetary Events
Credit: Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)
To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html
Times are Eastern Daylight Time. Some additions made to aid clarity.
Date Local Event
Time EST
Dec 01 Tu Venus: 43.3° W 03 Th 2:41am Last Quarter 04 Fr 1:21am Moon-Jupiter: 2° N 04 Fr 1:33pm Moon Ascending Node 05 Sa 9:56am Moon Apogee: 404800 km 05 Sa 9:40pm Moon-Mars: 0.1° N - Occultation ** 07 Mo 11:55am Moon-Venus: 0.7° S - Occultation * 11 Fr 5:29am New Moon 12 Sa 3:15am Moon South Dec.: 18.4° S 14 Mo 12:48pm Geminid Shower: ZHR = 120 17 Th 9:32pm Saturn-Antares: 6.2° N 18 Fr 10:13am Moon Descending Node 18 Fr 10:14am First Quarter 21 Mo 3:53am Moon Perigee: 368400 km 21 Mo 11:48pm Winter Solstice 22 Tu 9:00pm Ursid Shower: ZHR = 10 23 We 9:16pm Mars-Spica: 3.5° N 23 We 2:09pm Moon-Aldebaran: 0.7° S 25 Fr 2:30am Moon North Dec.: 18.4° N 25 Fr 6:11am Full Moon 28 Mo 9:59pm Mercury Elongation: 19.7° E 29 Tu 3:30pm Moon-Regulus: 2.9° N 31 Th 12:55pm Moon-Jupiter: 1.6° N 31 Th 3:19am Moon Ascending Node Jan 01 Fr Venus: 37.9° W
* The occultation will be visible in the US, except extreme southwestern Alaska and Hawai’i; and Canada down to Panama. In the Grand Traverse area of Michigan the occultation starts around 12:20 p.m. and ends around 1:27 p.m. This is a daytime event for most of the US. Note that the actual time depends on your exact location. I’ll have more information in a non Ephemeris post on Saturday the 5th. The Occultation map is here.
** On December the 5th there will be an occultation of Mars visible across the Indian Ocean and much of Australia. That occultation map is here.
Estimating occultation timings for your location
I used Cartes du Ciel the free software that I have a link to on the right. Make sure that the program is set for topocentric positions under Setup/Solar System. And you have entered your position under Setup/Observatory. You can find your location in Google Earth, or your GPS device or smart phone.
You can also use Stellarium. Just make sure the Moon is normal sized.
In both programs you can lock the Moon or Aldebaran in the center of the screen Pick a time in advance of the occultation and using the set time window walk the star towards the Moon, mark the time. Then walk the star out from the Moon and record the reappearance time. That’s it.
This should work with other planetarium programs too.
For better accuracy go to the International Occultation Timing Association (IOTA) website. Download and install their Occult4 program for Windows computers. Follow the instructions. When I ran the program for my location, the location I use for Interlochen/Traverse City (Since I live approximately half-way between the two). I got results within a half-minute of the IOTA Occult4 program results. So the approximation method using planetarium programs is valid.
Comet C/2013 US10 (Catalina)
This comet has been hiding for the last two years after its discovery, moving into the far southern hemisphere of the sky. However this month it has emerged into our morning sky. This comet is a one time visitor from the Oort Cloud to the inner solar system and will be ejected into interstellar space. It passed perihelion on November 15th, coming just inside the Earth’s orbit on the other side of the Sun from us. It’s orbit will be headed northward and a bit toward us, so it will keep its brightness steady.
The position marks in the chart have the date and the magnitude. However the comet is currently appearing one magnitude dimmer than shown. So instead of appearing as nearly 5th magnitude, it will really be 6th magnitude. It’s definitely a binocular or telescopic object.
According to the brightness graph the comet began to under perform in brightness back in September, however, according to a new brightness formula the comet may increase in brightness by a magnitude by late February when it will be well placed for viewing all night. To monitor the brightness reports from observers go to http://www.aerith.net/comet/catalog/2013US10/2013US10.html.
The tracks of Comet C/2013 US10 (Catalina) for December 2015 along with part of Venus’ track. Created using Cartes du Ciel (Sky Charts).
11/25/2015 – Ephemeris – The occultation of Aldebaran is tomorrow morning!
Ephemeris for Wednesday, November 25th. The Sun will rise at 7:52. It’ll be up for 9 hours and 14 minutes, setting at 5:06. The Moon, at full today, will rise at 5:26 this evening.
Tomorrow morning between about 5:38 and 6:29 a.m. the Moon will pass in front of the bright star Aldebaran. The event is called an occultation. Aldebaran is the bright reddish star in the V-shaped face of the constellation Taurus the bull, which is seen in the sky charging Orion the hunter in the evening sky now. By the time of this event, they will have moved into the west. Aldebaran, though bright, doesn’t hold a candle to the nearly full Moon. I know that a holiday is a good day to sleep in, unless you are getting an early start on preparing the Thanksgiving feast. In any case the earlier you get out to spot Aldebaran the easier it will be to find in the Moon’s glare. Check out my posts on bobmoler.wordpress.com for more information.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Here’s the Moon hiding Aldebaran in its glare at 5:30 a.m. tomorrow morning November 26, 2015. Created using Stellarium.
An occultation animation starting at 5:19 a.m. EST showing 10 minute intervals. Computer generated graphics cannot produce a point star. Aldebaran will wink out and back in an instant. Created using Cartes du Ciel (Sky Charts) and GIMP.
11/23/2015 – Ephemeris – An occultation of Aldebaran by the Moon will be visible to much of the northern US Thursday morning
Ephemeris for Monday, November 23rd. The Sun will rise at 7:49. It’ll be up for 9 hours and 18 minutes, setting at 5:08. The Moon, 2 days before full, will set at 5:58 tomorrow morning.
Thursday morning, Thanksgiving Day here in the US, the Moon will occult or pass in front of the bright star Aldebaran for the northern half of the United States, and Canada. I have a special post on my blog dated yesterday, November 22nd. It’s titled Aldebaran Occultation November 26, 2015 from Northern Michigan (click here) with all the details. My blog is bobmoler.wordpress.com, or do an Internet search for Bob Moler, That’s Moler spelled M-O-L-E-R, no extra letters. Aldebaran is the bright orange star in the face of the constellation Taurus the bull. You will need at least a pair of binoculars to pick out Aldebaran next to the Moon. Aldebaran will disappear at about 5:38 a.m. and reappear about 6:29 a.m. for Interlochen and Traverse City.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location. The November 22 post has instructions on how to calculate the occultation times for your location, and has a map to see if you can view the occultation at all.
Addendum
An occultation animation starting at 5:19 a.m. EST showing 10 minute intervals. Not that the computer generated graphics cannot produce a point star. Aldebaran will wink out and back in an instant. Created using Cartes du Ciel (Sky Charts) and GIMP.
Bob Moler's Ephemeris Blog 