03/21/2023 – Ephemeris Extra – Spring has sprung without me

Being in the hospital and now in inpatient rehab one loses a sense of time. So the vernal equinox snuck by me unnoticed. My view of the outside world is another part of the hospital, a part of the HVAC system, and a piece of sky.

Yesterday, the Sun passed over the Earth’s equator, heading northward. The Sun is gradually setting at the South Pole and rising at the North Pole. Folks like me who live in the Northern Hemisphere are experiencing longer daylight than those south of the equator, who are beginning autumn. The daylight hours will increase daily until June 21st, the summer solstice. In the Interlochen/Traverse City area, that will be 15 hours and 34 minutes.

The cause of the Earth’s seasons is not our varying distance from the Sun in our eliptical orbit of the Sun of 93 million plus or minus a million and a half miles.By the way, the Earth is currently moving away from the Sun. It will be farthest from the Sun around July 4th or 5th.

Our perception of the advance of spring, besides the gradully warming temperatures and increasing daylight hours, will be the height of the Sun’s path in the sky, and the position of the Sun’s rise and set points on the horizon. All these annual changes are angles having to do with one’s latitude (an angle), Earth’s position in orbit (an angle), and the tilt of the Earth’s axis to it’s orbit (more angles).

Bob

06/20/2022 – Ephemeris – Here we are at the last full day of spring

This is Ephemeris for Juneteenth, Observed, Monday, June 20th. Today the Sun will be up for 15 hours and 34 minutes, setting at 9:31, and it will rise tomorrow at 5:57. The Moon, at last quarter today, will rise at 2:09 tomorrow morning.

Here we are at the last full day of spring. Summer will begin at 5:14 EDT, or 9:14 UT tomorrow morning, when the Sun reaches its highest point on the celestial sphere, and directly over the northern latitude line called the Tropic of Cancer. At that time, folks at or north of the Arctic Circle at about 66 ½ degrees north latitude won’t see the Sun set. As it is, Interlochen is only about 4 degrees latitude south of the land of the all night twilight. It’s neat, around here in the western part of the Lower Michigan, to go out around midnight and see a bit of the last twilight glow near the north. Remember that around here, local or astronomical midnight occurs around 1:45 am. Ah politicians, aren’t they wonderful. And they’ve just made Daylight Saving Time permanent.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

The event at 5:14 am EDT or 9:14 UT is called the summer solstice, or in deference to our Southern Hemisphere neighbors, the June solstice, because for them winter is starting. Solstice means “Sun stands still”. It doesn’t, of course. The sun is always moving eastward against the stars. However, if one checks the altitude of the Sun in the south at local noon each day, the Sun would move higher each day since the winter solstice until around June 21st, and go no further. It would slowly begin a retreat, day by day. That pause at the highest point is the solstice.

03/19/2021 – Ephemeris – Enjoy this last full day of winter!

This is Ephemeris for Friday, March 19th. Today the Sun will be up for 12 hours and 7 minutes, setting at 7:54, and it will rise tomorrow at 7:45. The Moon, 2 days before first quarter, will set at 2:23 tomorrow morning.

Spring is almost here. It will arrive at 5:37 tomorrow morning, so this is the last full day of winter, such as it was. That point in time and the point in the sky where the Sun crosses the celestial equator, the imaginary line in the sky above the Earth’s equator, heading northward is called the vernal equinox. Vernal means spring and equinox means equal night, meaning that day and night are equal, which they actually were last Tuesday. Since western civilization has spread south of the equator where the seasons are reversed, our Northern Hemisphere spring equinox is the Southern Hemisphere’s autumnal equinox, so to be understandable to both hemispheres we generally say March or September equinox instead.

Addendum

The Sun’s path through the sky on an equinox day from the Traverse City/Interlochen area in Michigan. The Sun is plotted every 15 minutes. This is a stereographic projection which compresses the sky near the zenith and enlarges the sky toward the horizon. Created using my LookingUp program.

03/20/2020 – Ephemeris – The first full day of spring

Ephemeris for Friday, March 20th. Today the Sun will be up for 12 hours and 11 minutes, setting at 7:55, and it will rise tomorrow at 7:43. The Moon, half way from last quarter to new, will rise at 7:00 tomorrow morning.

Spring snuck up on us at 11:50 p.m. last night, so this is the first full day of spring. That point in time and the point in the sky where the Sun crossed the celestial equator the imaginary line in the sky above the Earth’s equator heading northward is called the vernal equinox. Vernal means spring and equinox means equal night, meaning that day and night are equal. Since western civilization has spread south of the equator where seasons are reversed, our northern hemisphere spring equinox is the southern hemisphere’s autumnal equinox, so to be fair to both hemispheres we generally say March or September equinox instead. However the point in the sky the Sun crossed last night will always be known as the vernal equinox.

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

Addendum

The Sun at the vernal equinox point on the celestial sphere at 11;50 p.m. EDT last night (March 19, 2020). The diagonal yellow line in the ecliptic, the Sun’s path in the sky. The vertical lines marked in hours at the top are lines of right ascension, the analog of earthly longitude. The horizontal lines are lines of declination, the same as latitude on the Earth. I referenced this point in yesterday’s program. Created using Cartes du Ciel *Sky Charts).

The Sun’s path through the sky on the equinox day from Traverse City, MI. Note that the Sun rises due east and sets due west. Created using my LookingUp program.

03/16/2020 – Ephemeris – The Fisher signals maple sugaring season

Ephemeris for Monday, March 16th. Today the Sun will be up for 11 hours and 58 minutes, setting at 7:50, and it will rise tomorrow at 7:50. The Moon, at last quarter today, will rise at 4:21 tomorrow morning.

As the weather warms up with days above freezing and nights below freezing its time to tap maple trees for their sweet sap. The Anishinaabe native people of this area had a legend that a magical animal called the Fisher, who brought summer to the Earth, signals this season by rising high in the northeast. The Fisher or Ojiig is seen in the stars where the official constellation of Ursa Major, the great bear and the popular asterism the Big Dipper is. The Fisher’s claim to immortality is that he and some of his animal friends were able to break through the dome of the sky to release the warm air from above to heat the Earth. For his trouble he was killed, but the Great Spirit placed him in the sky where we see him today.

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

Addendum

Finding the Big Dipper and the Fisher around 9 p.m. Click on the image to enlarge. Created using Stellarium and GIMP.

 

03/18/2016 – Ephemeris – Spring comes this weekend!

Ephemeris for Friday, March 18th.  The Sun will rise at 7:48.  It’ll be up for 12 hours and 4 minutes, setting at 7:53.   The Moon, 3 days past first quarter, will set at 5:48 tomorrow morning.

Sunday’s the day I’ve been waiting for.  Maybe you feel that way too.  Because at 12:31 a.m. EDT (4:31 a.m. UT) Sunday March 20th the season of spring will begin.  It’s not that we’ve had a hard winter.  As winters go this has been a mild one.  The Grand Traverse Bay never froze over.  My heating bill has been low.  Of course we have a chance for another snow storm or two before May gets here.  However at the top of the show notice we’re getting over 12 hours of sunlight even now.  The sun will reach its peak altitude of about 45 degrees at local noon.  Those at the Straits will have to wait only a few more days for he Sun to reach that altitude.  The Sun is rapidly moving northward, and the daylight hours are increasing by about 3 minutes a day.

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

Addendum

Getting close to the equinox. Earth image from NOAA DSCOVR satellite’s Epic camera in a halo orbit around the Earth-Sun Lagrangian point 1, a million miles Sunward of the Earth. Taken March 14, 2016.

The Sun’s path through the sky from due east to due west on the equinox day from Traverse City, MI. Created using my LookingUp program.

That’s not a pumpkin on the head of the motorcyclist. That’s the Sun rising as I’m traveling east on South Airport Road south of Traverse City Mi. on the autumnal equinox. This is the east-west section of the road. The Sun is rising over the hills some 6 miles to the east. Credit: Bob Moler.

Traverse City’s latitude is 1/3º south of 45º north latitude.  The Suns are plotted at 15 minute intervals.  Each day the Sun will rise higher and higher until the summer solstice when the Sun’s path in the sky looks like this:

The Sun’s path through the sky on the summer solstice day from Traverse City, MI. Created using my LookingUp program.

For those south of the equator, summer is ending and autumn is starting.

03/01/2016 – Ephemeris – Previewing March skies

Ephemeris for Tuesday, March 1st.  The Sun will rise at 7:19.  It’ll be up for 11 hours and 11 minutes, setting at 6:31.   The Moon, at last quarter today, will rise at 2:15 tomorrow morning.

Let’s look at the skies for the month of March. The sun will pass the celestial equator as the promising season of spring will begin.  Daylight hours in the Interlochen/Traverse City area and will increase from  11 hours and 11 minutes today to 12 hours 45 minutes on the 31st.  The altitude, or angle, of the sun above the southern horizon at local noon will be 38 degrees today and will ascend to nearly 50 degrees on the 31st.  Jupiter will reach opposition from the Sun on the 8th and enter the evening sky.  That evening our time a total solar eclipse will be visible from Indonesia to the Pacific Ocean.  Spring will begin on the 20th at 12:31 a.m.  Easter, announced by the full moon on the 23rd will be celebrated on the 27th for western churches.

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

Addendum

March Star Chart

Star Chart for March 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 10 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 7:34 p.m. EST on the 1st, increasing to 9:14 p.m. EDT on the 31st.

Morning astronomical twilight starts at 6:16 a.m. EDT on the 1st, and decreasing to 6:20 a.m. EST on the 31st.

Add a half hour to the chart time every week before the 15th and subtract a half hour for every week after the 15th.  Before the 13th also subtract an hour for Standard Time.

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
• A leaky Big Dipper drips on Leo
• Follow the arc of the handle of the Big Dipper to the star Arcturus

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  Time(EST) Event
Mar 01  Tu          Venus: 24.9° W
    01  Tu  6:11 pm Last Quarter
    02  We  1:53 am Moon-Saturn: 3.9° S
    03  Th  9:19 am Moon South Dec.: 18.2° S
    07  Mo  5:54 am Moon-Venus: 3.5° S
    08  Tu  4:58 am Jupiter Opposition from the Sun
    08  Tu  8:54 pm New Moon
    08  Tu  8:58 pm Total Solar Eclipse* (Indonesia & Pacific)  
    09  We  1:31 am Moon Descending Node
    10  Th  2:02 am Moon Perigee: 359500 km
    13  Su  2:00 am Daylight Saving Time starts (EDT) Boo Hiss!
    14  Mo  9:44 am Moon-Aldebaran: 0.3° S
    15  Tu  1:03 pm First Quarter
    16  We  1:01 am Moon North Dec.: 18.2° N
    20  Su 12:31 am Vernal Equinox – Yea Spring!
    20  Su  3:05 pm Moon-Regulus: 2.8° N
    21  Mo 11:57 pm Moon-Jupiter: 2.3° N
    22  Tu  8:58 pm Moon Ascending Node
    23  We  7:48 am Penumbral Lunar Eclipse (not visible from here)
    23  We  8:01 am Full Moon
    23  We  4:05 pm Mercury Superior Conjunction with the Sun
    25  Fr 10:16 am Moon Apogee: 406100 km
    28  Mo  2:45 pm Moon-Mars: 4.6° S
    29  Tu 10:58 am Moon-Saturn: 3.8° S
    30  We  6:12 pm Moon South Dec.: 18.2° S
    31  Th 11:17 am Last Quarter
Apr 01              Venus: 17.4° W

* Coverage on NASA-TV-2 & www.exploratorium.edu/eclipse from 8 p.m. to 9 p.m.

Comet Catalina

Comet Catalina has become too faint to be seen in binoculars as it heads out of the solar system.  To follow the comet further go to Seiichi Yashida’s Weekly Bright Comets page. Comet Catalina is no longer the brightest comet on the list, and is currently listed second.  Click on it [C/2013 US10 ( Catalina )] for finder charts and other information.

When last we saw the comet was headed toward the constellation.  But it’s headed almost straight away from the Earth now, and the Earth’s motion around the Sun is making the comet appear to start a loop north of Perseus.  Another proof that Copernicus was right.

 

 

 

03/20/2015 – Ephemeris – Spring will spring forth at 6:44 p.m. EDT

Ephemeris for Friday, March 20th.  The Sun will rise at 7:46.  It’ll be up for 12 hours and 8 minutes, setting at 7:55.  The Moon is new today, and won’t be visible.

The Arctic solar eclipse has just ended.  But there is one more event of note today.  At 6:44 p.m.  The Sun will cross the celestial equator heading northward, the projection of the Earth’s equator on the sky.  In doing that the season of spring will return to the northern hemisphere.  The Sun is already staying up for just over half the day.   That will increase to fifteen and a half hours by the summer solstice three months from now.  Not only will the Sun will be out longer, but it will rise higher in the sky, rising from 45 degrees altitude in the south at local noon to 69 degrees on June 21st.  If the sun stayed at this location it would get very uncomfortable with the heat.  As it is as the Sun is climbing down it will still get warmer.  Peak summer heat occurs about a month after the solstice.

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

Addendum

These are whole sky diagrams with the edge at the horizon.  The Sun’s motion is from left to right.  The Sun is plotted every 15 minutes.  The Sun’s motion is constant, however the projection causes squeezing of the positions near the zenith (center of the diagram) and stretching near the horizon.

The sun’s daily path through the sky from horizon to horizon on an equinox the first day of spring or autumn. Credit My LookingUp program.

The sun’s daily path through the sky from horizon to horizon on the first day of summer, the summer solstice. Credit My LookingUp program.

02/28/2014 – Ephemeris – Looking forward to March and spring

Ephemeris for Friday, February 28th.  The sun will rise at 7:21.  It’ll be up for 11 hours and 7 minutes, setting at 6:29.   The moon, 1 day before new, will rise at 7:11 tomorrow morning.

Let’s look at the skies for the month of March. The sun will pass the celestial equator in March as the promising season of spring will begin.  Daylight hours in the Interlochen/Traverse City area and will increase from  11 hours and 10 minutes tomorrow to 12 hours 43 minutes on the 31st.  The altitude, or angle, of the sun above the southern horizon at local noon will be just under 38 degrees tomorrow and will ascend to nearly 50 degrees on the 31st.  The altitude of the sun in the Straits area will be a degree lower.  Local apparent noon this month, when the sun passes due south, will be about 12:49 p.m.  Spring will begin on the 20th at 11:57 a.m.  Eastern Daylight Time (15:57 UT), which now rules most of the year and will start a week from Sunday.

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

Addendum

Star Chart for mid-month for March 2014 at 10 p.m.  Credit: Bob Moler.

Add a half hour to 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.

03/19/2013 – Ephemeris – PanSTARRS, of course, plus a spring preview

Ephemeris for Tuesday, March 19th.  The sun will rise at 7:47.  It’ll be up for 12 hours and 6 minutes, setting at 7:53.   The moon, at first quarter today, will set at 3:38 tomorrow morning.

Comet PanSTARRS continues to be seen low in evening twilight.  It is moving now into the west northwest.  When it becomes dark enough it will display a fan shaped tail in binoculars.  It is moving away from both the sun and the earth.  Tomorrow will see our own milestone as the earth moves into a position where the sun appears over the earth’s equator, and the sun sets at the south pole of the earth and rises at the north pole.  It will be the vernal or spring equinox.  Australians and other folks south of the equator may prefer to call it the March equinox, because for them autumn starts.  The exact time the sun will appear to cross the equator heading northward will be 7:02 tomorrow morning.  The sun will keep heading northward until June 21st.

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

Addendum

Comet PanSTARRS for this week’s weekdays at 9:15 p.m. Created using Stellarium and Cartes du Ciel.

The earth as seen from the sun near the vernal equinox. See the earth from north pole to south pole. Created using Celestia.