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11/05/2017 – Ephemeris Extra – There will be an Occultation of Aldebaran tonight*

November 5, 2017 1 comment

This posting will not be broadcast.

* Or tomorrow morning, depending where you are.

Ephemeris extra for Sunday, November 5th. The Sun will rise at 7:25. It’ll be up for 10 hours and 5 minutes, setting at 5:25. The Moon, 2 days past full, will rise at 7:01 this evening.

Tonight just after 8 p.m. the bright star Aldebaran will disappear at the left edge of the Moon. Aldebaran is angry red eye of Taurus the bull. The star will reappear at the dark upper right edge of the Moon. Start looking at 8 p.m. or before. Use binoculars or a small telescope to spot the star against the glare of the bright Moon. The star is nowhere as bright as shown in the illustrations below. Star appearances and disappearances appear instantaneous, unlike what the illustrations show.

Aldebaran Occultation begins at 8:07 p.m. EST (1:07 UTC Nov 6th)
Aldebaran Occultation ends at 9:00 p.m. EST (02:00 UTC Nov 6th)

Note the times are for the Traverse City/Interlochen area. It will vary by a few minutes for northern lower Michigan.  The position angles of the entrance and exit points of Aldebaran will also be different.

Otherwise use a planetarium program like Stellarium to preview the event. However, set the program for topocentric coordinates. In Stellarium that’s in the Configuration window, Tools Tab and check the Topocentric coordinates box. Topocentric coordinates are the apparent positions for your location on the Earth. So also make sure your location is correct. The geocentric conjunction of the two bodies will be November 6, 2:42.9 UTC, so it will occur after midnight on the morning of November 6th for locations in northern Europe and Asia.

Addendum

Occultation Map

Occultation Map for the occultation of Aldebaran by the Moon . Credit Occult 4 program from IOTA.org.

Occultation start

Aldebaran at the start of the occultation at 8:07 p.m. for the Traverse City/Interlochen area. Created using Stellarium.

Occultation end

Aldebaran at the end of the occultation at 9:00 p.m. for the Traverse City/Interlochen area. Created using Stellarium.

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11/03/2017 – Ephemeris – The Sun is the topic at tonight’s GTAS meeting

November 3, 2017 Comments off

Ephemeris for Friday, November 3rd. The Sun will rise at 8:23. It’ll be up for 10 hours and 5 minutes, setting at 6:28. The Moon, 1 day before full, will set at 8:35 tomorrow morning.

This evening the Grand Traverse Astronomical Society will hold its monthly meeting at the Northwestern Michigan College’s Rogers Observatory at 8 p.m. with a program featuring member Don Flegel in a talk about the Sun. Don’s the keeper of our solar telescope and wanted a good excuse to learn more about the Sun, so he decided to study up and give this talk. That’s how I do it.

After the talk, at 9 p.m. there will be a star party, if it’s clear, to view the heavens including the Moon. The observatory is located south of Traverse City, on Birmley Road between Garfield and Keystone roads.

It’s time to change our clocks again at 2 a.m. Sunday. Turn your clocks back one hour. That’s Fall Back one hour for a bit of extra sleep.

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

Addenda

Don Flegel at Fishtown

Don Flegel, in the foreground, with the society’s solar telescope assisting a person viewing the Sun at he Leland Heritage Festival 2017 at Fishtown.  Man in the background in the blue cap is Gary Carlisle.  The telescope in the middle is mine.

Occultation of Aldebaran by the Moon Sunday Night

Occultation Map

Occultation Map for the occultation of Aldebaran by the Moon . Credit Occult 4 program from IOTA.org.

For the Traverse City/Interlochen area:

Aldebaran Occultation start 8:07 p.m. Nov 5th (01:07 UT Nov 6th)
Aldebaran Occultation end 9:00 p.m. Nov 5th (02:00 UT Nov 6th)

I’ll have an Ephemeris Extra posting, Sunday November 5th with more information.

10/13/2017 – Ephemeris – The bright star Regulus dips behind the Moon Sunday morning

October 13, 2017 1 comment

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 start

Occultation of Regulus by the Moon disappearance at around 5:47 a.m. for northern Michigan. Created using Stellarium.

Occultation end

Occultation of Regulus by the Moon reappearance at around 6:25 a.m. for northern Michigan. Created using Stellarium.

Occultation Map

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

September 12, 2017 Comments off

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

Occultation map

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

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.

Aldebaran and the Moon at 8:35 a.m. September 12, 2017. Created using Stellarium.

Aldebaran reappearing from behind the Moon

Aldebaran reappearing from behind the Moon at 9:53 a.m. September 12, 2017. Created using Stellarium.

 

03/03/2017 – Ephemeris – Astronomy talk and star party tonight and the occultation of Aldebaran tomorrow night

March 3, 2017 Comments off

Ephemeris for Friday, March 3rd.  The Sun will rise at 7:15.  It’ll be up for 11 hours and 17 minutes, setting at 6:33.  The Moon, 2 days before first quarter, will set at 12:36 tomorrow morning.

Tonight the Grand Traverse Astronomical Society will present a talk by Becky Shaw on international observatories at 8 p.m. at Northern Michigan College’s Rogers Observatory.  Also tonight at the observatory, there will be viewing of the Moon and other wonders of the March skies.  Tomorrow night shortly after 11 p.m. the bright star Aldebaran in Taurus the bull will be covered or occulted by the Moon for about half of the IPR listening area.  It will be seen by observers south of a line from Leland to south of Mancelona centered on 11:13 p.m.  The farther south one is the longer the occultation will last.  Start looking by 11 p.m. and check my yesterday’s blog post for more information.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

03/02/2017 – Ephemeris – Saturday night’s occultation of the bright star Aldebaran

March 2, 2017 Comments off

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.

Occultation map

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

Occultation Graze

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.

Occultation of Aldebaran

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

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.

Graze results

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

December 12, 2016 Comments off

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.

Occultation start

Start of the occultation at 11:54 p.m EST December 12, 2016. The grid is altitude and azimuth. Created using Cartes du Ciel.

Occultation start

End of the occultation at 12:09 a.m EST December 13, 2016. The grid is altitude and azimuth. Created using Cartes du Ciel.

Occultation visibility path

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.

Occultation animation

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.