Archive
10/13/2017 – Ephemeris – The bright star Regulus dips behind the Moon Sunday morning
Note: The original program recorded for this day was erroneous in the timing and appearance of this event. Occurring about an hour later than reported here. The Interlochen personnel may or may not replace the original program with the one below. Also those who downloaded the audio from ephemeris.bjmoler.org before late Thursday night may have downloaded the incorrect mp3.
Ephemeris for Friday, October 13th. The Sun will rise at 7:55 a.m.. It’ll be up for 11 hours and 5 minutes, setting at 7:00 p.m. The Moon, 1 day past last quarter, will rise at 2:08 tomorrow morning.
On Sunday morning the Moon will pass in front of, or occult the bright star Regulus, the brightest star in Leo the lion. This will happen as morning twilight starts. Regulus will disappear at the left edge of the crescent Moon at around 5:47 a.m. A telescope or binoculars may be needed to spot Regulus. Go out at least 5 or 10 minutes early to make sure you can spot the star. Regulus will reemerge at 6:25 at the 11 o’clock position on the dark part of the Moon. Earth shine on the night side of the Moon may be bright enough to see its dark edge. Observers west of us in the United States except the northern most states west of Minnesota will also get a view. Those in specific locations in the northern tier of states will get to see Regulus just graze the north edge of the Moon.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Occultation of Regulus by the Moon disappearance at around 5:47 a.m. for northern Michigan. Created using Stellarium.
Occultation of Regulus by the Moon reappearance at around 6:25 a.m. for northern Michigan. Created using Stellarium.
Map showing the locations where the occultation of Regulus will be visible. For the area bounded by heavy lines the occultation will occur at night. Click on image to enlarge. Credit: Occult4 by IOTA.
09/12/2017 – Ephemeris – The Moon will hide the bright star Aldebaran after sunrise this morning
Ephemeris for Tuesday, September 12th. The Sun will rise at 7:18. It’ll be up for 12 hours and 40 minutes, setting at 7:58. The Moon, 1 day before last quarter, will rise at 12:13 tomorrow morning.
This morning during daylight at around 8:40*. the bright star Aldebaran will disappear behind the Moon. Binoculars or a small telescope can be used to spot Aldebaran, the bright star in the constellation Taurus the bull’s eye. Taurus and the rest of the winter constellations are visible before sunrise. The sky needs to be absolutely clear to be able to spot the event. The star will be seen to approach the bright side of the Moon. The star will reappear around 9:53 a.m.* on the dark western edge of the Moon. These events are called occultations. They come from the word occult, which means hidden. In actuality the solar eclipse of three weeks ago was a spacial case of an occultation for those in the path of totality.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
* The disappearance and appearance times for Aldebaran are within a couple of minutes for Western Michigan. For other locations in the occultation path Stellarium will give pretty good times for the events by modeling the occultation as I did below. Like a solar eclipse where you are determines the timing of the event.
Addendum
Map of where the occultation is visible. For the area bounded in red, the occultation is visible in the daytime. Credit: Occult4 by IOTA.
Position of the Moon in the sky near the start of the occultation, 8:35 a.m. September 12, 2017. Created using Stellarium.
Aldebaran and the Moon at 8:35 a.m. September 12, 2017. Created using Stellarium.
Aldebaran reappearing from behind the Moon at 9:53 a.m. September 12, 2017. Created using Stellarium.
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.
12/12/2016 – Ephemeris – The Moon will cover the eye of the bull tonight
Ephemeris for Monday, December 12th. The Sun will rise at 8:11. It’ll be up for 8 hours and 51 minutes, setting at 5:02. The Moon, 1 day before full, will set at 7:21 tomorrow morning.
Late tonight the nearly full moon will pass in front of the bright star Aldebaran. This will be a difficult event to spot due to the brightness of the Moon. It will take a telescope at least to spot Aldebaran, the bright star the is the bloodshot eye in the face of Taurus the bull. It might help to spot Aldebaran an hour or two early, while it’s some distance left of the Moon. Aldebaran will disappear at the Moon’s left edge, while its a tiny distance from the bright edge of the Moon at around 10:54 p.m. Aldebaran will reappear at about 12:09 a.m. Make sure to start observing several minutes early since these are low precision times, plus your location affects the times. These times are most accurate in the Western Lower Peninsula of Michigan.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon moves from west to east, so the occultation events will happen earlier to the west and later to the east. Planetarium programs can be used to simulate the position of the Moon and stars and can be used to estimate the occultation start and end times. To be accurate your location longitude and latitude must be entered in the program.
The times I developed are from the free program Cartes du Ciel and are within a minute of that provided by the more accurate program Occult4, which can be downloaded for free at the site below. Planetarium programs are close enough, however. Occult4 is somewhat difficult to use.
If you’re out keep a look out for some bright Geminid Meteors. Their shower will reach its peak tomorrow night.
Start of the occultation at 11:54 p.m EST December 12, 2016. The grid is altitude and azimuth. Created using Cartes du Ciel.
End of the occultation at 12:09 a.m EST December 13, 2016. The grid is altitude and azimuth. Created using Cartes du Ciel.
Path of the occultation. Locations between the bright boundaries would see the occultation at night. Created by the software program Occult4 by the International Occultation Timing Association.
An animation created by Occult4 of the occultation of Aldebaran and some of the dimmer stars of the Hyades.
Eclipse and occultation information and software can be accessed at http://occultations.org/ the website of IOTA, the International Occultation Timing association.
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/
04/08/2016 – Ephemeris – Daytime occultation of Aldebaran Sunday the 10th
Apr 8. This is Bob Moler with Ephemeris for Friday, April 8th. The Sun will rise at 7:09. It’ll be up for 13 hours and 9 minutes, setting at 8:19. The Moon, 1 day past new, will set at 10:03 this evening.
The Moon will pass in front of the bright star Aldebaran Sunday evening. However it will still be daylight out. So this will be a challenge for the observer with binoculars, or better yet, telescope. The moon will appear as a washed out crescent in the blue sky. It will require an exceptionally clear sky to see Aldebaran, which once the Sun sets will appear just below the Moon and is part of the Face of Taurus the bull. For the IPR listening area Aldebaran will disappear at the Moon’s dark upper left edge at 6:29 p.m. plus or minus a minute, depending on your location. The star will reappear at 7:38 p.m., give or take a minute, on the right edge of the Moon, just below the dark oval of the Sea of Crises. This is second of 4 Aldebaran occultations visible from here this year.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Ingress: 6:29 p.m.
Aldebaran ingress at approximately 6:29 p.m. April 10, 2016. Created using Stellarium.
Egress: 7:38 p.m.
Aldebaran egress at approximately 7:38 p.m. April 10, 2016. Created using Stellarium.
Occultation Visibility Map
Occultation Map for Aldebaran. Bright outline of occultation path is where it occurs at night. Credit IOTA program Occult 4.
Aldebaran will most likely need a telescope to spot once the Moon is located. The representations above via Stellarium will show the star as being too bright. It will be quite dim in relation to the sky brightness. The Moon too will be washed out. Start searching before the occultation start to make sure the star can be located. Even a little haze will make seeing the event impossible.
The actual time of the ingress and egress will vary by several minutes depending on your location in Michigan. Stellarium or other planetarium programs can be used to predict the timings to within a minute. IOTA the http://www.lunar-occultations.com/iota/iotandx.htm has a free Windows program Occult 4 which will give accurate occultation and transit of Mercury predictions.
01/19/2016 – Ephemeris – The Moon will cover Aldebaran tonight!
Ephemeris for Tuesday, January 19th. The Sun will rise at 8:14. It’ll be up for 9 hours and 18 minutes, setting at 5:32. The Moon, 3 days past first quarter, will set at 4:51 tomorrow morning. | Tonight the Moon will pass in front of or occult the bright star Aldebaran, the bright star in Taurus the bull. The bright Moon will making spotting Aldebaran difficult without binoculars, or better yet, a telescope. Aldebaran will wink out at the Moon’s dark eastern or left edge around 9:06 p.m. The exact time depends on your location. It’s within a minute or 2 for the IPR listening area. Aldebaran will be uncovered by the Moon around 10:25 p.m. at the bright lower right edge of the Moon. Today’s posting on bobmoler.wordpress,com will have much more information on the event, and how to calculate times for other locations along the path of the occultation (see below). This is the best of the four Aldebaran occultations visible this year.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Occultation visibility map for January 19, 2016 EST (January 20 UT). Credit IOTA/Occult4 program. Looks like the followers of this blog in the UK will get a piece of this one too.
Aldebaran will disappear at the Moon’s dark leading edge at about 9:06 p.m. January 19, 2016. Created using Cartes du Ciel (Sky Charts).
Aldebaran will reappear at the Moon’s bright trailing edge at about 10:25 p.m. January 19, 2016. Created using Cartes du Ciel (Sky Charts).
Estimating 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.
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.
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.
Bob Moler's Ephemeris Blog 