12/31/2017 – Ephemeris Extra – January 2018 preview

This isn’t going to be recorded as an actual program.  I’m not sure how much information one could retain at 6 or 7 New Years Day morning.

Year end is a busy time astronomically with Earth’s perihelion and the Quadrantid meteor shower following rapidly on New Years day

Let’s look ahead at January 2018. Tuesday the 2nd is the date of the latest sunrise. The Sun is already beginning to head north, as can be seen in the sunset time on the 1st, 11 minutes later than at its earliest three weeks ago. Both sunrise and sunset will be moving in January with sunrise time at 8:20 a.m. and sunset time at 5:12 p.m. on the 1st moving to 8:02 a.m. and 5:50 p.m. at month’s end. The sun’s altitude at noon will increase from 22 degrees on the 1st to nearly 28 degrees by the 31st. The Earth will reach its closest to the Sun in its orbit, called perihelion, on the 2nd at 91.4 million miles (147.1 million km).

We’ll have a full moon on the 1st and the 31st, the so-called blue moon.  Both those moons will be super moons, occurring at or near perigee.  On  top of all that the  full moon on the 31st will be totally eclipsed.  We in Michigan will see nearly the first half of the eclipse before the Moon sets at 8:04 in the grand Traverse area.  Folks farther west will see more, if not all of the eclipse. February will have no full moons, so March again will have two full moons.

The Quadrantid meteor shower will reach peak on the 3rd, in the afternoon.  The radiant is circumpolar here, being off the handle of the Big Dipper.  Mercury will reach its greatest western elongation on the 1st and be visible shortly before sunrise for the next week rising after 6:30, but brightening a bit each day.  It’s not a particularly favorable elongation, now that winter is here.  The next evening elongation in  March will be a lot better.  Venus will be in superior conjunction with the Sun on the 9th and will enter the evening sky, but don’t look for it this month.  Mars and Jupiter will have a close conjunction on the 6th.  It will look about equally OK on the morning of the 6th or 7th around here because it occurs on the evening of the 6th, when they are not up.

Addenda

January Evening Sky Chart

Star Chart for January 2018 (9 p.m. January 15, 2018). Created using my LookingUp program. Click on image to enlarge.

The planets and stars are plotted for the 15th at 9 p.m. EST in the evening and 6 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 9 p.m. and 6 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. For planet positions on dates other than the 15th, check the Wednesday planet posts on this blog.

January Morning Star Chart

Star Chart for January 2018 mornings based on 6 a.m. January 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.
• The Summer Triangle is in red
• QuadR is the Quadrantid meteor shower radiant. Peaks on January 2nd, but the almost full moon will interfere this year.

Twilight

Evening nautical twilight ends at 6:22 p.m. EST on the 1st, increasing to 6:55 p.m. EST on the 31st.
Evening astronomical twilight ends at 6:57 p.m. EST on the 1st, increasing to 7:29 p.m. EST on the 31st.
Morning astronomical twilight starts at 6:35 a.m. EST on the 1st, and decreasing to 6:23 a.m. EST on the 31st.
Morning nautical twilight starts at 7:10 a.m. EST on the 1st, and decreasing to 6:57 a.m. EST on the 31st.

NASA Calendar of Planetary Events

    Date    Time    Event
Jan 01  Mo          Venus: 1.9° W
    01  Mo  2:59 pm Mercury Elongation: 22.7° W
    01  Mo  4:54 pm Moon Perigee: 356600 km
    01  Mo  7:01 pm Moon North Dec.: 20.1° N
    01  Mo  9:24 pm Full Moon
    02  Tu  9:59 pm Perihelion: 0.9833 AU
    03  We  2:50 pm Moon-Beehive: 2.3° N
    03  We  3:19 pm Quadrantid Meteor Shower: ZHR = 120
    04  Th  2:48 am Moon Ascending Node
    05  Fr  2:24 am Moon-Regulus: 0.9° S
    06  Sa  7:39 pm Mars-Jupiter: 0.2° N
    08  Mo  5:25 pm Last Quarter
    09  Tu  1:16 am Venus Superior Conjunction w/Sun
    11  Th 12:59 am Moon-Jupiter: 4.7° S
    13  Sa  2:58 am Mercury-Saturn: 0.7° N
    14  Su  9:09 pm Moon Apogee: 406500 km
    14  Su  9:13 pm Moon-Saturn: 2.9° S
    15  Mo 11:28 am Moon South Dec.: 20° S
    16  Tu  9:17 pm New Moon
    18  Th  9:28 am Moon Descending Node
    24  We  5:20 pm First Quarter
    27  Sa  5:09 am Moon-Aldebaran: 0.7° S
    29  Mo  6:32 am Moon North Dec.: 20° N
    30  Tu  4:54 am Moon Perigee: 359000 km
    31  We  2:19 am Moon-Beehive: 2.3° N
    31  We  8:27 am Full Moon
    31  We  8:30 am Total Lunar Eclipse (See Below)
    31  We  1:46 pm Moon Ascending Node
Feb 01  Th          Venus: 5.7° E

Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC),
http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html

If you go to the above site you can print out a list like the above for the entire year
or calendar pages for your time zone.

Sun and Moon Rising and Setting Events

     LU                  Ephemeris of Sky Events for Interlochen/TC
     January, 2018    Local time zone: EST
     +-----------------------------------------------------------------------+
     | DATE |  SUN     SUN  DAYLIGHT|   TWILIGHT*    |MOON  RISE OR    ILLUM |
     |      |  RISE    SET    HOURS |  END    START  |PHASE SET** TIME FRACTN|
     +=======================================================================+
     |Mon  1| 08:20a  05:13p  08:52 | 06:23p  07:09a |Full  Rise 05:11p  100%|
     |Tue  2| 08:20a  05:13p  08:53 | 06:24p  07:09a |      Rise 06:18p   99%|
     |Wed  3| 08:20a  05:14p  08:54 | 06:25p  07:10a |      Rise 07:30p   95%|
     |Thu  4| 08:20a  05:15p  08:55 | 06:25p  07:10a |      Rise 08:44p   88%|
     |Fri  5| 08:19a  05:16p  08:56 | 06:26p  07:10a |      Rise 09:56p   80%|
     |Sat  6| 08:19a  05:17p  08:58 | 06:27p  07:09a |      Rise 11:05p   70%|
     +------+-----------------------+----------------+-----------------------+
     |Sun  7| 08:19a  05:19p  08:59 | 06:28p  07:09a |      Rise 12:12a   60%|
     |Mon  8| 08:19a  05:20p  09:00 | 06:29p  07:09a |L Qtr Rise 01:17a   49%|
     |Tue  9| 08:19a  05:21p  09:02 | 06:30p  07:09a |      Rise 02:19a   39%|
     |Wed 10| 08:18a  05:22p  09:03 | 06:31p  07:09a |      Rise 03:20a   30%|
     |Thu 11| 08:18a  05:23p  09:05 | 06:32p  07:09a |      Rise 04:19a   22%|
     |Fri 12| 08:18a  05:24p  09:06 | 06:33p  07:08a |      Rise 05:16a   14%|
     |Sat 13| 08:17a  05:25p  09:08 | 06:34p  07:08a |      Rise 06:11a    8%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 14| 08:17a  05:27p  09:10 | 06:36p  07:08a |      Rise 07:02a    4%|
     |Mon 15| 08:16a  05:28p  09:11 | 06:37p  07:07a |      Rise 07:49a    1%|
     |Tue 16| 08:15a  05:29p  09:13 | 06:38p  07:07a |New   Set  05:21p    0%|
     |Wed 17| 08:15a  05:31p  09:15 | 06:39p  07:06a |      Set  06:17p    1%|
     |Thu 18| 08:14a  05:32p  09:17 | 06:40p  07:06a |      Set  07:15p    3%|
     |Fri 19| 08:14a  05:33p  09:19 | 06:41p  07:05a |      Set  08:15p    8%|
     |Sat 20| 08:13a  05:34p  09:21 | 06:42p  07:05a |      Set  09:17p   14%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 21| 08:12a  05:36p  09:23 | 06:44p  07:04a |      Set  10:20p   21%|
     |Mon 22| 08:11a  05:37p  09:25 | 06:45p  07:04a |      Set  11:24p   30%|
     |Tue 23| 08:10a  05:38p  09:28 | 06:46p  07:03a |      Set  12:30a   40%|
     |Wed 24| 08:10a  05:40p  09:30 | 06:47p  07:02a |F Qtr Set  01:38a   51%|
     |Thu 25| 08:09a  05:41p  09:32 | 06:48p  07:01a |      Set  02:48a   62%|
     |Fri 26| 08:08a  05:43p  09:34 | 06:50p  07:01a |      Set  03:59a   72%|
     |Sat 27| 08:07a  05:44p  09:37 | 06:51p  07:00a |      Set  05:09a   82%|
     +------+-----------------------+----------------+-----------------------+
     |Sun 28| 08:06a  05:45p  09:39 | 06:52p  06:59a |      Set  06:14a   90%|
     |Mon 29| 08:05a  05:47p  09:42 | 06:53p  06:58a |      Set  07:13a   96%|
     |Tue 30| 08:04a  05:48p  09:44 | 06:55p  06:57a |      Set  08:04a  100%|
     |Wed 31| 08:02a  05:50p  09:47 | 06:56p  06:56a |Full  Rise 06:15p  100%|
     +-----------------------------------------------------------------------+
     * Nautical Twilight
     ** Moonrise or moonset, whichever occurs between sunrise and sunset

Total Lunar Eclipse January 31, 2018

I’ll have more on this toward the end of the month. Credit NASA.

The original page for this graphic is:  https://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2018Jan31T.pdf

    Total Lunar Eclipse January 31
Event               Time EST   Time UT
                    GT Area    
Enter penumbra      5:51 a.m.  10:51   Unseen
Begin partial phase 6:48 a.m.  11:48
Totality begins     7:51 a.m.  12:51
Moon sets           8:04 a.m.
Mid eclipse                    13:28
Totality ends                  14:07
End partial phase              15:11
Leave penumbra                 16:08   Unseen

The shading of the penumbra is generally seen within 1/2
hour before and after the partial begins and ends.

Update

Our bird feeder at about 2 p.m. It was cleaned off and filled 6 hours before. Dining are a downy woodpecker, behind the suet block; a flicker with a seed in its beak and three chickadees. Can you spot the third?

While I was writing this post on the afternoon of the 30th, we were getting a rather intense lake effect snow storm, at about an inch an hour.  By nightfall the snow on top of the feeder just about reached the hook.  We also get cardinals, blue jays, sparrows.   Poor juncos.  They seem to feed on the ground, and the snow came too fast and covered the seed that had dropped, so they were looking in vain.

I really love the chickadees, they’re fearless.  When I’m filling the bird feeder the other birds scatter, but the chickadees sit in the tree, a couple of feet over my head and wait patiently until I hang it back up.

12/29/2017 – Ephemeris – Last occultation of the star Aldebaran by the Moon is tomorrow night

Ephemeris for Friday, December 29th. The Sun will rise at 8:19. It’ll be up for 8 hours and 51 minutes, setting at 5:10. The Moon, half way from first quarter to full, will set at 5:08 tomorrow morning.

We have one last cool astronomical event that can be seen from here in 2017. Of course, weather permitting. Tomorrow night the Moon will occult the bright star Aldebaran in Taurus the bull from 6:17 to 7:17 p.m. I’m not dabbling with the black arts here, even though I’m using the Occult 4 program to find it. In astronomy occult is a verb meaning to hide, and the event is called an occultation. The Moon will appear to move in front of, or hide the star Aldebaran. At 6:17 p.m. Aldebaran will disappear at the dark edge of the Moon at its 8 o’clock position. Binoculars will be needed to spot the star against the glare of the bright Moon before the event. Aldebaran will pop out from behind the Moon at a bit above the 3 o’clock position at 7:17 p.m.

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

Addendum

Occultation visibility map for the occultation of Aldebaran by the Moon for us in the Unites States, the early evening of December 30, 2017. Created using Occult 4 by IOTA.

Occultation start 6:17 p.m. December 30, 2017. as seen from the Grand Traverse area of Michigan. Actual times may vary depending on your location. Created using Stellarium.

Occultation end 7:17 p.m. December 30, 2017. as seen from the Grand Traverse area of Michigan. Actual times may vary depending on your location. Created using Stellarium.

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 December, 31, 0:49.2 UT, so it will occur after midnight on the morning of December 31st for locations in northern Europe and Asia.

Program Note

The January preview will be an Ephemeris Extra post on December 31st.

 

 

12/28/2017 – Ephemeris – Two astronomical highlights in 2017

Ephemeris for Thursday, December 28th. The Sun will rise at 8:18. It’ll be up for 8 hours and 50 minutes, setting at 5:09. The Moon, 2 days past first quarter, will set at 3:54 tomorrow morning.

In my book 2017 has been not so nice of a year. However astronomically speaking, there were at least two notable bright spots. The first was the Great American Solar Eclipse, August 21st that was visible coast to coast. Though I didn’t choose the best spot in Fayette Missouri I did witness the eclipse under hazy skies, and did record the Moon’s shadow passing over us. The other actually occurred four days earlier, but wasn’t announced to the public for months later. The detection via gravity waves, gamma rays, X-rays, visible light, infrared, and radio waves of a pair of neutron stars colliding. This is the new field multi-messenger astronomy. A quarter of all professional astronomers were involved with the event.

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

Addendum

Total solar eclipse, August 21, 2017

A composite image of something like 70 exposures of the Sun’s corona taken August 21, 2017 by Scott Anttila, former president of the GTAS.

August 21, 2017 total solar eclipse sky from Fayette MO, with an action camera looking at the eclipse and sky, watching the Moon’s shadow pass over us from behind us on the right to the left, with quick looks right and left. Photography and processing by Bob Moler.

Neutron star merger discovered August 17, 2017

Optical discovery and fading of SSS17a aka GW170817 by Swope & Magellan Telescopes.

Neutron Star Collision GW170817 timeline. Horizontal axis in seconds (exponential). From the High Energy Stereoscopic System website.

12/27/2017 – Ephemeris – All the bright planets are in the morning sky. However the Moon is in the evening sky.

Ephemeris for Wednesday, December 27th. The Sun will rise at 8:18. It’ll be up for 8 hours and 50 minutes, setting at 5:08. The Moon, 1 day past first quarter, will set at 2:43 tomorrow morning.

Let’s take our weekly look at the bright planets. While Uranus and Neptune are evening planets, they require binoculars or a telescope to spot. All of the bright naked eye planets are in the morning sky now, However Saturn and Venus, the brightest are too close to the Sun to be seen. At 7 this morning Mars is in the south-southeast while Jupiter is a lot brighter and below and left of it. Mars will rise tomorrow morning at 3:49. It’s approaching Jupiter which will rise 23 minutes later at 4:12. Mercury will be a challenge to spot, rising in the east-southeast at 6:32 a.m. both today and tomorrow. At 7 a.m. It will require a low horizon, binoculars and luck to find. In its next evening appearance in March it will be placed much higher in the sky for the same twilight conditions.

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

Addendum

The only bright solar system object visible in the evening is the gibbous Moon. Binoculars will reveal several large craters this evening December 27, 2017. Created using Stellarium.

Three planets are visible at 7 in the morning. Created using Stellarium.

Jupiter and its four Galilean moons as they might be seen in a telescope at 7 a.m. this morning, December 27, 2017. Created using Cartes du Ciel (Sky Charts).

Earlier in the morning both Io and Europa will be eclipsed in Jupiter’s shadow and be occulted by the planet.

Moon    Event           UT       Time in Traverse Area
Europa: Eclipse start   5:15 UT
Io:     Eclipse start   6:43 UT
Europa: Occultation end 9:27 UT  4:27 a.m. EST
Io:     Occultation end 9:47 UT  4:47 a.m. EST

Planets at sunset and sunrise of a single night starting with sunset on the right on December 27, 2017. The night ends on the left with sunrise on the 28th. Click on the image to enlarge. Created using my LookingUp program.

 

12/26/2017 – Ephemeris – Help for that Christmas telescope

Ephemeris for Tuesday, December 26th. The Sun will rise at 8:18. It’ll be up for 8 hours and 49 minutes, setting at 5:08. The Moon, at first quarter today, will set at 1:34 tomorrow morning.

Get a telescope for Christmas? Or is there one lurking in a closet or attic? Tonight’s a good time to get it out, if it’s clear, because there’s a first quarter Moon out. I consider the Moon round the first quarter to provide the finest viewing.  To get started, most astronomical telescopes have a small finder scope attached. Daytime is the best time to align them on a distant object. To find anything, even the Moon, use the lowest power eyepiece. In most scopes that’s a 20 to 25 millimeter eyepiece. Eyepieces with lower numbers are higher power. Most amateur astronomers use their lowest magnification 90% of the time. The bright planets right now are in the morning sky, and only Jupiter is worth looking at. It’s easy to find because it’s the brightest star-like object, and in the southeast before 7:30 a.m. To help you further, on January 5th, at Northwestern Michigan College’s Rogers Observatory the Grand Traverse Astronomical Society will host its annual Telescope Clinic for telescopes new and old.

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

Addendum

Here’s a handout we make available at these telescope clinics:

Telescope Basics

                           Telescope Types

There are two basic telescope types: The refractor or refracting telescope and reflector or reflecting telescope. The reflecting type shown is a Newtonian telescope, is the simplest and most inexpensive reflector. The Catadioptric (Mirror-Lens) telescope uses a corrector plate in front of the telescope. The one shown is a type called a Maksutov-Cassegrain. The more popular type is the Schmidt-Cassegrain which uses a thin, nearly flat corrector plate. The Cassegrain design uses a convex secondary mirror the sends the light back through a hole in the Primary mirror (O) to an eyepiece.

Refracting telescopes get expensive in a hurry as the diameter of the objective (O) lens increases due to the requirements of at least 4 lens surfaces of the at least two lenses that make it up. The reason for it is to correct for color fringes that would result around bright objects seen through it (chromatic aberration), and the optical quality of the glass required. Reflectors primary mirror have a single surface and the glass simply supports it. The corrector plates of the catadioptric telescopes don’t create chromatic aberration because they don’t bend light much. Telescopes are rated by the diameter of their objectives (O). One could purchase an 11 inch Newtonian telescope for less than $1,000, An 11” Schmidt-Cassegrain for $2,500, or an 11” refractor for the cost of a Lexus.

The reason astronomers go for wider telescopes (greater aperture) is two-fold: To gather more light to better see faint objects, and to increase resolving power, the ability of the telescope to see fine detail and be able to use higher magnification. We’ll see the rules when we talk about eyepieces.

Telescope Mounts

There are four basic mounts. Equatorial mounts have to be aligned to the earth’s axis in order to work properly to follow objects in the sky. Alt-Azimuth mounts are the simplest and easiest to set up, but all but the most sophisticated cannot be made to track objects in the sky as the Earth rotates. A relatively new addition to mounts is the computerized “Go To” feature allows the telescope to find objects itself when the mount is properly aligned to the sky. Telescopes with Dobsonian mounts have the largest aperture for the buck. Cheap telescopes tend to have cheap mounts that are hard to use and wobbly, especially the ones with German equatorial mounts. An alt-azimuth mount would be steadier and a whole lot easier to use in this case.

Finder Telescopes

The telescope eyepiece covers so little area of the sky to make finding anything virtually impossible. So all telescopes have small finder scopes attached of 6 to 10 power, or 1 power devices that put a finder circle or red dot on the sky when you look through them. A newer finder idea is a mount for a green laser that projects a beam in the atmosphere toward the object to be located. The author prefers a finder with an aperture of at least 50mm to be able to see most of the dim objects he’s looking for. In the main telescope, use the lowest power eyepiece because it has the widest field of view.

Eyepieces

Magnifying power or magnification is not a telescope property. The eyepiece is essentially a magnifying glass to view the real image that the objective lens or mirror produces at the focal plane (F) in the telescope type diagram on the first page. The focal length of the objective lens or mirror or the effective focal length of the mirrors of the catadioptric telescope divided by the focal length of the eyepiece gives the magnification of that particular combination of telescope and eyepiece. The focal length of the eyepiece is marked on the eyepiece. The telescope focal length may or may not be stamped or marked on the telescope, if not, check the owner’s manual for that quantity.

A telescope will generally come with one or two eyepieces, The lowest power eyepiece will generally be a 25mm eyepiece of some kind. Eyepieces come in 2 standard barrel sizes, 1 ¼ inch and 2 inch. There are some old telescopes that only accept sub 1 inch eyepieces. You may have to hunt to see if any of those size eyepieces are still around. The cheaper the telescope the crummier the eyepiece. Decent eyepieces start at around $35 and go up from there. The best way to tell which eyepiece fits your needs is to ask an astronomer what eyepiece he or she is using at a star party.

About magnification. The highest usable magnification in a telescope is calculated as the aperture in millimeters times 2.4 or aperture in inches times 60. After that the image becomes fuzzy and dim. It’s due to the wave nature of light. I halve those values in his experience. I’d rather have small crisp images than big fuzzy ones devoid of contrast.

A handy accessory to have is a Barlow lens, a negative lens in a tube, that the eyepiece is slipped in before inserting the pair in the eyepiece holder. It will double the power of the eyepiece. So with two eyepieces and a Barlow four separate magnifications are available. The author would rather us a lower power eyepiece with a Barlow than a high power eyepiece of the same power. In that same vein a good low power wide-angle eyepiece is generally the first extra eyepiece astronomers purchase. More expensive ones can be like viewing the universe in IMAX. Here is a truism: Amateur astronomers use their telescope’s lowest power 90% of the time.

Solar filters that fit over the front of the telescope and finder is a fine addition to any telescope and allow viewing of our star close up. Some old telescopes have a solar filter that fits in an eyepiece. For your visual health take the filter and beat it to death with a hammer, and throw it away. There are also filters that can filter out some of the light pollution for dim nebulae. There are filters also to bring out detail in planets.

Above all, have fun! If you have any questions ask that friendly amateur astronomer over there, standing by his or her telescope at the next star party.

12/25/2017 – Ephemeris – The 3 and 2 BC “Star of Bethlehem” conjunctions were repeated 3 and 2 years ago

Merry Christmas. This is Ephemeris for Christmas Day, Monday, December 25th. The Sun will rise at 8:18. It’ll be up for 8 hours and 49 minutes, setting at 5:07. The Moon, 1 day before first quarter, will set at 12:28 tomorrow morning.

August three years ago and June two years ago we had a near repeat of two very close conjunctions of Jupiter and Venus that occurred in 3 and 2 BC. These two conjunctions spaced by a month more than the human gestation period and seen against the constellation of Leo the lion, symbol of Judah could have brought the Magi, who were Persian astrologer-priests to Jerusalem, capital of Judea. The events could have signified the them the birth of a king of Judea. It was the interpretation of the scriptures by the scribes that actually sent them to Bethlehem. This version of the Star of Bethlehem seems to be the one that’s being accepted more and more by those who believe the Star had a physical reality.

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

Addendum

I dredged these up from the Ephemeris archives

June 16, 2 BC just after sunset Jupiter and Venus again cross paths, at one point too close to be separated with the naked eye. Created using Stellarium.

Jupiter-Venus approach animation June 11 to July 1, 2015 at 10:30 p.m. Created using Stellarium and GIMP. Click on image to enlarge.

A link to the 2015 posting is here.  I didn’t realize until later that this was a near repeat of the 3 ans 2 BC conjunctions.  Here’s a link to my posting of the August conjunction.

 

12/22/2017 – Ephemeris – The joining of a god and goddess, a second possibility of the Star of Bethlehem

Ephemeris for Friday, December 22nd. The Sun will rise at 8:16. It’ll be up for 8 hours and 48 minutes, setting at 5:05. The Moon, half way from new to first quarter, will set at 9:21 this evening.

On Tuesday I talked about what I said was one of two possible physical explanations for the Star of Bethlehem. Here is the second. On August 13th of 3 BC Jupiter and Venus briefly merged in the pre-dawn skies against the constellation of Leo the lion. A month later Jupiter was in conjunction with Regulus the bright star in Leo, the little king star. Then 9 months later, after sunset on June 16th of 2 BC the two planets again joined as one in Leo. The king of the planets twice mating with Venus as Ishtar, the Babylonian goddess of fertility, against the constellation of the lion signifying Judah in Genesis? One might find meaning in all that, especially the Magi, who were Zoroastrian astrologer-priests from Persia.

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

Addendum

Animation of the Jupiter-Venus conjunction of August 13, 3 BC. in the morning twilight. Created using Stellarium.

June 16, 2 BC just after sunset Jupiter and Venus again cross paths, at one point too close to be separated with the naked eye. Created using Stellarium.

 

12/21/2017 – Ephemeris – Winter begins this morning

Ephemeris for Thursday, December 21st. The Sun will rise at 8:16. It’ll be up for 8 hours and 48 minutes, setting at 5:05. The Moon, 3 days past new, will set at 8:23 this evening.

The thermometer and snowfall tell us that winter ought to be here. Well it will be at 11:29 this morning. At that point the Sun will be directly over the Tropic of Capricorn at 23 ½ degrees south latitude. Odd name because 2,000 years ago the Sun was in indeed entering Capricornus. Now it’s entering in Sagittarius, right above the spout of the teapot asterism we know so well in summer. From then on the Sun will be climbing up the sky each noon until June 21st next year when summer will start. To which I say Go Sun Go! The Sun will barely make it to 22 degrees above the southern horizon at local noon in Interlochen and be out for only 8 hours and 48 minutes. If it stayed that low all year we’d be in a deep freeze possibly colder than Antarctica.

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

Addendum

DSCOVR satellite’s Earth Polychromatic Camera image of the Earth at 18:09 UTC (1:09 p.m.) December 19, 2017. We’re way up at the top just under the clouds at the top. It was actually partly cloudy that day. The DSCOVR satellite was in a halo orbit about the Earth-Sun L1 point, 934,498 miles (1,503,929 km) toward the Sun from Earth.

The Sun is shown against the celestial sphere at the moment of the December solstice. Saturn will be in conjunction later in the day, heading to the right along the ecliptic, which is the path of the Sun. Venus will pass the Sun, heading to the left on January 9th. The grid lines are right ascension in hours (h) and declination in degrees. The solstice occurs when the Sun crosses the 18 hour line. Note the Teapot asterism that is part of Sagittarius. Created using Stellarium.

12/20/2017 – Ephemeris – All the visible bright planets are in the morning sky

Ephemeris for Wednesday, December 20th. The Sun will rise at 8:15. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The Moon, 2 days past new, will set at 7:27 this evening.

Let’s take our weekly look at the bright planets. There are no bright planets visible in the evening sky now. While Uranus and Neptune are evening planets, they require binoculars or a telescope to spot. The morning sky is now host to three planets, though Venus, the brightest will rise too close to the Sun to spot. It’s way on the other side of the Sun, and it will pass behind the Sun in superior conjunction January 9th. At 7 this morning Mars is in the southeast while Jupiter is a lot brighter and below and left of it. Mars will rise tomorrow morning at 3:54. It’s approaching Jupiter which will rise 39 minutes later at 4:33. Tomorrow Saturn will be in conjunction with the Sun and will officially enter the morning sky. It will be a month or more before it separates far enough from the Sun to spot in morning twilight.

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

Addendum

The only bright solar system object visible in the evening is the thin crescent Moon that will be exhibiting Earth shine this evening December 20, 2017. Created using Stellarium.

The bright morning planets visible at 7 a.m. this morning, December 20, 2017. Mercury is too close to the horizon to spot. Created using Stellarium.

Jupiter and its four Galilean moons as they might be seen in a telescope at 7 a.m. this morning, December 20, 2017. Created using Cartes du Ciel (Sky Charts).

Planets at sunset and sunrise of a single night starting with sunset on the right on December 20, 2017. The night ends on the left with sunrise on the 21st. Click on the image to enlarge. Created using my LookingUp program.

12/19/2017 – Ephemeris – Were celestial events in 7 BC interpreted as the Star of Bethlehem?

Ephemeris for Tuesday, December 19th. The Sun will rise at 8:15. It’ll be up for 8 hours and 49 minutes, setting at 5:04. The Moon, 1 day past new, will set at 6:34 this evening.

This year we have no bright evening Christmas star. But what about the one described in the Bible, in the gospel of Luke? We will look today at the first of two events that may have been recorded as the Star of Bethlehem. In 7 BC there was a rare event over 6 months when three times the planet Jupiter passed Saturn against the stars of the constellation Pisces. Could the Persian astrologer priests called Magi, have read into the event enough significance to start the journey to Jerusalem in search of the new born King of the Jews? It was the scribe’s readings that then sent them to Bethlehem. It is thought that Pisces was associated with the Hebrews, Jupiter with the Messiah or world ruler, and Saturn with the peoples of Palestine.

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

Addendum

The Jupiter-Saturn triple conjunction of 7 BC. Click on the image to enlarge. Created using Cartes du Ciel.

The animation above shows the planets at 5 day intervals in 7 and a bit in 6 BC.  The normal or posigrade motion is toward the east or left.  When an outer planet approaches its opposition from the Sun, it seems to slow and reverse direction and head westward for a time, which is retrograde motion.  After a time it reverses and heads back eastward again.  That’s why the planets seem to see-saw back and forth.  Jupiter passes Saturn every 20 years.  The next time will be in 2020.  On my Wednesday planet charts Jupiter is seen sneaking up on Saturn week by week.  In order to have three conjunctions instead of one, the planets need to be near opposition from the Sun when they pass.  The last time that happened was in 1980, but it wasn’t against Pisces.  Triple conjunctions against a particular zodiacal constellation are much rarer.

The dates for key events in the animation above are:

• First Conjunction May 29, 7 BC
• Planets are Stationary July 6, and begin retrograde motion
• Second Conjunction October 11
• Planets are Stationary November 1 and resume posigrade motion
• Third Conjunction on December 8
• Mars joins February 26, 6 BC

Retrograde motion was difficult to explain when one thinks that the Earth is the center of the Universe and stationary, while the planets supposedly orbited in perfect uniform circular motion around it.  It’s easy when the Earth is a moving planet like the rest.  When an outer (superior) planet is at opposition from the Sun.  The Earth is between the Sun and planet and moving faster.  So we’re passing the outer planet.  When you are in a car passing another, the car being passed seems to move backward with respect to your car.  Since the planets orbits are like a race track, we get to lap the outer planets at regular intervals.