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Posts Tagged ‘Autumnal equinox’

09/20/2018 – Autumn will fall on us Saturday night

September 20, 2018 Comments off

Ephemeris for Thursday, September 20th. The Sun will rise at 7:27. It’ll be up for 12 hours and 16 minutes, setting at 7:43. The Moon, half way from first quarter to full, will set at 3:44 tomorrow morning.

Welcome to the last few days of summer. The weather has stayed summery thus far through September. The Sun will reach the autumnal equinox point in the sky at 9:54 Saturday evening. At that moment the Sun will cross the celestial equator, a projection of the Earth’s equator, heading southward. All locations on the Earth except two will experience 12 hours of daylight and 12 hours of night. Well they would if the Earth didn’t have an atmosphere and sunset and sunrise were defined differently. The two locations that don’t experience equal night, which is what equinox means, are the north pole where the Sun will be setting and the south pole where the Sun will be rising. For us in the northern hemisphere daylight hours will be shorter and the Sun will peak lower in the south each day until the December solstice.

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

Sun's path through the sky on the equinox
The Sun’s path through the sky on the equinox day from Traverse City, MI.  Local noon, when the Sun is due south, is 1:35 p.m. EDT.   Created using my LookingUp program.

09/21/2017 – Ephemeris – Summer ends and autumn begins tomottow

September 21, 2017 1 comment

Ephemeris for Thursday, September 21st. The Sun will rise at 7:28. It’ll be up for 12 hours and 12 minutes, setting at 7:41. The Moon, 1 day past new, will set at 8:45 this evening.

Enjoy the last full day of summer. Summer will last until 4:02 p.m. (20:02 UTC) tomorrow when the center of the Sun will cross the celestial equator, an imaginary line above the Earth’s equator, heading southward. At that instant autumn will begin. Shortly the Sun will be up less than half the day. The day and the point in the sky that the Sun crosses is called the autumnal equinox. The word equinox means equal night, implying that day and light are of equal length. Geometrically that’s true, but the Earth’s atmosphere and the definition of sunrise and sunset, prolong daylight by a few minutes. The amount of heat we are getting and will get from the Sun cannot sustain our current temperatures, and it will get a lot colder before it gets warmer again.

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

Addendum

Autumnal equinox from space

Image from the Earth Polychromatic Imaging Camera (EPIC) on NOAA’s DSCOVR satellite in halo orbit around the Earth-Sun L-1 point 1 million miles sunward from the Earth last autumnal equinox (2016) at about the same time the autumnal equinox will occur this year.

Sunrise on the autumnal equinox

That is 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.

09/22/2016 – Ephemeris – Autumn will begin this morning

September 22, 2016 Comments off

Ephemeris for Thursday, September 22nd.  The Sun will rise at 7:30.  It’ll be up for 12 hours and 8 minutes, setting at 7:39.  The Moon, 1 day before last quarter, will rise at 12:06 tomorrow morning.

Fall is about to a, well… fall upon us and in a few weeks so will the leaves.  At 10:21 (14:21 UT) this morning the Sun will cross the celestial equator heading south.  The celestial equator is an imaginary line in the sky above the earth’s equator.  At that point the sun will theoretically set at the north pole and rise at the south pole.  The day is called the autumnal equinox and the daylight hours today is 12 hours and 8 minutes instead of 12 hours exactly.  That’s due to our atmosphere and our definition of sunrise and sunset.  The reason for the cooler weather now and the cold weather this winter is that the length of daylight is shortening, and the Sun rides lower in the sky, spreading its heat over a larger area, thus diluting its intensity.

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

Addendum

The Earth near the autumnal equinox

The Earth as seen a couple of days ago from NOAA,s DSCOVR satellite located near the Sun-Earth L-1 point 1 million miles sunward from the Earth. Credit NOAA/NASA.

Sun's path through the sky on the equinox

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

 

09/01/2016 – Ephemeris – Previewing the pivotal month of September’s skies

September 1, 2016 Comments off

Ephemeris for Thursday, September 1st.  The Sun will rise at 7:05.  It’ll be up for 13 hours and 12 minutes, setting at 8:18.  The Moon is new today, and won’t be visible.

There’s an eclipse of the Sun in progress now for parts of the southern hemisphere centered on southern Africa.  Today is also has the first of two new Moons this month, the second being called the Black Moon.  Let’s look at the skies for September. The sun is moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 12 minutes today to 11 hours 44 minutes on the 30th. The altitude of the sun above the southern horizon at local noon will be 54 degrees today, and will descend to 42 degrees on the 30th. The official season of summer is getting short too, so enjoy it while you can.  Summer ends and autumn begins at 10:21 a.m. on September 22nd.

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

Addendum

September Star Chart

September Star Chart

Star Chart for September 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. EDT.  That is chart time.  Note, Traverse City is located approximately 45 minutes behind our time meridian.  (An hour 45 minutes behind our daylight saving time meridian.) To duplicate the star positions on a planisphere you may have to set it to 1:45 earlier than the current time if you are near your time meridian.

Evening nautical twilight ends at 9:24 p.m. EDT on the 1st, increasing to 8:27 p.m. EDT on the 30th.

Morning nautical twilight starts at 5:59 a.m. EDT on the 1st, and decreasing to 6:37 a.m. EDT on the 30th.

Add a half hour to the chart time every week before the 15th and subtract a half hour for every week after the 15th.

For a list of constellation names to go with the abbreviations click here.

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star
  • Follow the arc of the handle of the Big Dipper to the star Arcturus
  • The Summer Triangle is outlined in red.  Vega in Lyra (Lyr), Deneb in Cygnus (Cyg) and Altair in Aquila (Aql).

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.

    Date    Time    Event
Sep 01  Th          Venus: 23.5° E
    01  Th  5:03 am New Moon
    01  Th  5:08 am Annular Solar Eclipse (Atlantic, Africa, Indian Ocean)
    01  Th 11:27 am Moon Ascending Node
    02  Fr 11:16 am Neptune Opposition
    03  Sa  6:33 am Moon-Venus: 1.2° S
    04  Su  8:03 pm Saturn-Antares: 6.1° N
    06  Tu  2:44 pm Moon Apogee: 405100 km
    08  Th  5:23 pm Moon-Saturn: 4.2° S
    09  Fr  7:49 am First Quarter
    10  Sa  6:05 am Moon South Dec.: 18.5° S
    12  Mo  7:38 am Mercury Inferior Solar Conjunction (Will enter the
                    morning sky)
    15  Th  7:55 pm Moon Descending Node
    16  Fr  2:56 pm Penumbral Lunar Eclipse (Not visible in MI)
    16  Fr  3:05 pm Full Harvest Moon
    18  Su 11:12 am Venus-Spica: 2.4° N
    18  Su  1:00 pm Moon Perigee: 361900 km
    21  We  6:13 pm Moon-Aldebaran: 0.2° S
    22  Th 10:21 am Autumnal Equinox (Summer ends and autumn starts)
    23  Fr  5:56 am Last Quarter
    23  Fr 12:44 pm Moon North Dec.: 18.5° N
    26  Mo  2:19 am Jupiter Solar Conjunction (Will enter the morning sky)
    27  Tu  6:32 pm Moon-Regulus: 1.8° N
    28  We  2:59 pm Mercury Greatest Elongation: 17.9° W
    28  We  6:06 pm Moon Ascending Node
    30  Fr  8:12 pm New Moon (Second new Moon this month)
Oct 01  Sa          Venus: 30.9° E

09/22/2015 – Ephemeris – Equinox tomorrow and September 27th Moon’s triple whammy

September 22, 2015 Comments off

Ephemeris for Tuesday, September 22nd.  The Sun will rise at 7:29.  It’ll be up for 12 hours and 11 minutes, setting at 7:40.   The Moon, 1 day past first quarter, will set at 2:02 tomorrow morning.

Tomorrow at 4:20 a.m. before most of us wake up summer will officially end and Autumn will start.  That’s the exact time of the autumnal equinox.  We are noticing that the days or rather daylight hours are getting noticeably shorter day by day.  Autumn will end when the days will stop getting shorter on the first day of winter, December 21st.  The full moon this Sunday is triply important.  Most important is that a total lunar eclipse will happen.  Second, it is the Harvest Moon, the nearest full moon to the autumnal equinox, more on that next week.  Also it is the closest the Moon gets to the Earth all year.  Yup it’s a so-called supermoon.  If the Moon were a 2 inch ball it would be 20 feet from an 8 inch Earth.  The supermoon is a foot closer.

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

Addendum

That last bit about the Moon being a two-inch ball will come in handy if you come to the Girl Scout Badge Bash at ECCO in Traverse City Thursday night.

08/31/2015 – Ephemeris – Previewing the skies of September – Part 1

August 31, 2015 Comments off

Ephemeris for Monday, August 31st.  The Sun will rise at 7:03.  It’ll be up for 13 hours and 18 minutes, setting at 8:21.   The Moon, 2 days past full, will rise at 9:31 this evening.

Let’s look forward to the skies of September. The sun will moving at its greatest speed in its retreat to the south. Daylight hours in the Interlochen/Traverse City area and will drop from 13 hours and 15 minutes tomorrow the 1st. to 11 hours 46 minutes on the 30th. The altitude of the sun above the southern horizon at local noon will be 54 degrees tomorrow, and will descend to 42 degrees on the 30th. The Straits area will see the sun a degree lower.  The season of summer is getting short, so enjoy it while you can. Summer ends and autumn begins at 4:20 a.m. on September 23rd.  Saturn is setting before midnight now, but Venus and Mars are appearing in the morning sky soon.  Tomorrow we’ll look at September’s lunar eclipse.

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

Addendum

Star Chart for September 2015

Star Chart for September 2015. Created using my LookingUp program.

The planets and stars are plotted for the 15th at 10 p.m. EDT.  That is chart time.  Note, Traverse City is located 1 hour 45 minutes behind our time meridian.  To duplicate the star positions on a planisphere you may have to set it to 1 hour 45 minutes earlier than the current time.

Evening astronomical twilight ends at 10:04 p.m. EDT on August 1st, decreasing to 9:02 p.m. EDT on the 30th..

Morning astronomical twilight starts at 5:19 a.m. EDT on August 1st, and increasing to 6:01 a.m. EDT on the 30th.

Add a half hour to the chart time every week before the 15th and subtract and hour for every week after the 15th.

For a list of constellation names to go with the abbreviations click here.

The green pointer from the Big Dipper is:

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.
  • Follow the arc of the Big Dipper’s handle to Arcturus.
  • The Summer Triangle is shown in red.

Calendar of Planetary Events

Credit:  Sky Events Calendar by Fred Espenak and Sumit Dutta (NASA’s GSFC)

To generate your own calendar go to http://eclipse.gsfc.nasa.gov/SKYCAL/SKYCAL.html

Times are Eastern Daylight Time on a 24 hour clock.  Some additions made to aid clarity.

Conjunctions like the Mars-Regulus: 0.8° N means Regulus will appear 0.8° north of Mars.

Sep 01 Tu Venus: 25° W
04 Fr 05:59 Mercury Elongation: 27.1° E
05 Sa 01:09 Moon-Aldebaran: 0.6° S Occultation?*
05 Sa 05:54 Last Quarter
06 Su 13:06 Moon North Dec.: 18.2° N
10 Th 01:53 Moon-Venus: 2.9° S
13 Su 02:41 New Moon
13 Su 02:55 Partial Solar Eclipse (Southern tip of Africa to Antarctica)
14 Mo 00:38 Moon Ascending Node
14 Mo 07:28 Moon Apogee: 406500 km
18 Fr 22:54 Moon-Saturn: 3.1° S
21 Mo 04:59 First Quarter
21 Mo 08:02 Moon South Dec.: 18.1° S
23 We 04:20 Autumnal Equinox
24 Th 15:38 Mars-Regulus: 0.8° N
27 Su 17:04 Moon Descending Node
  27  Su 21:46 Moon Perigee: 356900 km – Super moon
27  Su 22:48 Total Lunar Eclipse
27 Su 22:50 Full Moon – Harvest Moon
30 We 10:36 Mercury Inferior Conjunction with the Sun
Oct 01 Th Venus: 43.6° W

* For the Grand Traverse Region the Moon will rise at 12:10 a.m. occulting Aldebaran.  Aldebaran will appear at the Moon’s unilluminated top right edge at approximately 12:40 a.m.

Note:  All lunar conjunctions in the table above are geocentric.  Double check with a program like Stellarium to check on the position of the body with respect to the moon for your location.

09/22/2014 – Epmemeris – Autumn begins tonight

September 22, 2014 Comments off

Ephemeris for Monday, September 22nd.  The sun will rise at 7:29.  It’ll be up for 12 hours and 10 minutes, setting at 7:39.   The moon, 2 days before new, will rise at 6:54 tomorrow morning.

Welcome to the last, almost full, day of summer.  The Sun will reach the autumnal equinox point in the sky at 10:30 this evening.  At that moment the Sun will cross the celestial equator, a projection of the Earth’s equator, heading southward.  All locations on the earth except two will experience 12 hours of daylight and 12 hours of night.  Well they would if the Earth didn’t have an atmosphere and sunset and sunrise were defined differently.  The two locations that don’t experience equal night, which is what equinox means, are the north pole where the sun will be setting and the south pole where the sun will be rising.  For us in the northern hemisphere daylight hours will be shorter and the Sun will peak lower in the south each day until the December solstice.

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

Addendum

Autumnal equinox

The Earth as seen from the direction of the Sun as it crosses over the Earth’s equator heading south. Created using Celestia.