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Posts Tagged ‘Sun’

09/03/2019 – Ephemeris – Yesterday and today conjunctions of Mars and Mercury with the Sun

September 3, 2019 Comments off

Ephemeris for Tuesday, September 3rd. Today the Sun will be up for 13 hours and 8 minutes, setting at 8:16, and it will rise tomorrow at 7:08. The Moon, 2 days before first quarter, will set at 10:59 this evening.

Yesterday morning Mars passed in conjunction with the Sun. For astronomers Mars was either just north or south of the Sun. In this case it was north of the Sun, moving from the evening or east side of the Sun to the west or morning side. Later this evening Mercury will pass in superior conjunction with the Sun. Mercury, being an inferior planet, that is one whose orbit is within Earth’s orbit of the Sun can pass between the Earth and the Sun in what we call an inferior conjunction or around the back side of the Sun in superior conjunction. In doing so Mercury is moving from the morning to the evening sky. Today the SOHO satellite will show both planets, the Sun and even Venus in its coronagraph.

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

Addendum

Mars in the C2 coronagraph

Solar and Heliospheric Observatory (SOHO) LASCO C2 Coronagraph image of the solar atmosphere at 8:24 p.m. September 2, 2019. A disk, called an occulting disk covers the bright Sun. The white circle is the size of the Sun’s photosphere. The white dot just about directly above the Sun is Mars, which is slowly heading to the right (west).

Venus and Mercury in the C2 coronagraph

SOHO LASCO C3 Coronagraph image of the solar atmosphere at 8:14 p.m. September 2, 2019. A disk, called an occulting disk covers the bright Sun. The white circle is the size of the Sun’s photosphere. Venus is the bright object to the left. It passed superior conjunction of the Sun back on September 14th. Mercury is just to the upper right of the occulting disk.  Both planets are heading to the left (east).

07/25/2017 – Ephemeris – Why do solar eclipses happen?

July 25, 2017 1 comment

Ephemeris for Tuesday, July 25th. The Sun rises at 6:21. It’ll be up for 14 hours and 54 minutes, setting at 9:15. The Moon, 2 days past new, will set at 10:48 this evening.

We have a day less than 4 weeks before the Great American Total Solar Eclipse on August 21st will occur. Solar eclipses occur at new moon, when the moon is aligned so its shadow falls on the Earth. It doesn’t happen every new moon because the Moon is a long ways away, and its orbit is tipped some 5 degrees from the Earth’s orbit of the Sun, so usually the Moon is north or south of the Sun at new moon. About one in every 6 new moons produces an eclipse. They occur when the Moon is near the crossing point of the two orbital planes, called nodes. The point where the Moon is passing the node in northward direction is called the ascending node, and 180 degrees around the orbit there is the descending node, but you have to be in the right spot to see an eclipse.

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

Addendum

Anatomy of an eclipse

What happens to create a total solar eclipse. Note the Sun’ distance as being 400 times the distance of the Moon. The Sun is also 400 times the Moon’s diameter, so they appear nearly the same size from the Earth. Credit NASA and the Eclipse2017.NASA.gov website.

08/28/2015 – Ephemeris – The last Friday Night Live of the summer

August 28, 2015 Comments off

Ephemeris for Friday, August 28th.  The Sun will rise at 7:00.  It’ll be up for 13 hours and 26 minutes, setting at 8:27.   The Moon, 1 day before full, will set at 6:47 tomorrow morning.

The Grand Traverse Astronomical Society will be at the last Friday Night Live of the year this evening to view the Sun and will stay after if its clear to view the Moon and Saturn in the telescopes.  For the Sun members have equipped their telescopes with solar filters to greatly diminish the sun’s light to make it safe to view the bright photosphere of the Sun with it’s sunspots.  The society itself has a solar telescope, that not only filters the Sun’s light, but filters the light to isolate the red light of the element hydrogen.  The special filter, called an etalon has to be tuned to the exact frequency or wavelength of the hydrogen atoms on the sun which will reveal the layer of gas above the photosphere and the clouds of hydrogen above.

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

Addendum

White light viewing of the Sun

Viewing the Sun with a while light filter at Friday Night Live using Ron Uthe’s telescope at Friday Night Live. Credit Bob Moler.

Solar Telescope

The Lunt solar telescope at another event. Credit Bob Moler.

06/22/2015 – Ephemeris – The summer full moon and the winter Sun trade places

June 22, 2015 Comments off

Ephemeris for Monday, June 22nd.  Today the Sun will be up for 15 hours and 34 minutes, setting at 9:32.   The Moon, 2 days before first quarter, will set at 1:04 tomorrow morning.  Tomorrow the Sun will rise at 5:57.

Summer’s here, and it’s a few days before the latest sunset and latest end of twilight.  It might be instructive to check out the height of the moon over the next two weeks or so.  The moon is heading south in front of the Sun.  The Sun besides its apparent westward motion during the day caused by the Earth’s rotation also moves about twice its diameter each day eastward against the stars caused by the earth’s motion in its orbit of the Sun.  Around July 1st, the moon will be about where the Sun will be next winter solstice, 4 days before Christmas.  Actually it will be about 8 moon widths above where the Sun will be because its orbit is tilted a bit to the Earth’s.  But it will serve as an illustration of the seasonal difference.

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

Addendum

Summer full moon

The full moon nearest the summer solstice. The full moon appears near where the sun would appear low in the south at the winter solstice. The bottom red line is the ecliptic, the path of the Sun. Created using Stellarium.

Moon near the winter solstice

The full moon nearest the winter solstice. The full moon appears near where the sun would appear high in the south at the summer solstice. The top red line is the ecliptic, the path of the Sun. Created using Stellarium.

The Moon’s orbit has a slight tilt of a bit more than 5 degrees from the ecliptic, or plane of the Earth’s orbit of the sun.  The crossing point is called a node.  In the bottom image the node near the western horizon is called the descending node due to the fact that the Moon is heading south of the ecliptic.  When the Sun and Moon are near the same node the Moon will be new and we have a chance for a solar eclipse.  When at opposite nodes, a lunar eclipse.  The nodes slowly slide westward slowly one revolution in about 18.6 years, which causes eclipse seasons, about 6 months apart to occur a bit earlier each year.

Categories: Concepts, Seasons, The Moon Tags: , , ,

05/03/2013 – Ephemeris – Explore the sun and the stars tonight

May 3, 2013 Comments off

Ephemeris for Friday, May 3rd.  The sun rises at 6:29.  It’ll be up for 14 hours and 20 minutes, setting at 8:49.   The moon, 1 day past last quarter, will rise at 3:39 tomorrow morning.

Yours truly will present a talk about the sun and its effects on the earth at this evening’s meeting of the Grand Traverse Astronomical Society at Northwestern Michigan College’s Rogers Observatory starting at 8 p.m.  This is a talk that is prepared to be given to the Friendly Garden Club later this month.  It explores how the sun gets its energy and it emphases the life-giving radiation we receive from the sun and how plants, especially use it to create our green oxygenated world.  Starting at 9 p.m. Is our first of our star parties for May at the observatory.  Highlights, if its clear will be the planets Jupiter and Saturn, plus some of the bright wonders of the spring skies and maybe a star cluster or two.  All are welcome.

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

03/29/2013 – Ephemeris –

March 28, 2013 2 comments

Ephemeris for Thursday, March 28th.  The sun will rise at 7:30.  It’ll be up for 12 hours and 34 minutes, setting at 8:05.   The moon, 1 day past full, will rise at 10:01 this evening.

Venus is passing superior conjunction with the sun today.  Superior means Venus is passing behind, thought not directly behind the Sun.  You can see it only in the images of the SOHO spacecraft.  On the Internet google soho nasa to find the site.   Our last inferior conjunction of Venus was the transit of Venus last June, when Venus crossed the face of the sun.  Mars is about to pass in conjunction with the sun.  All its conjunctions are superior.  For about a month, starting April 4th. the satellites and rovers cannot receive transmissions from the earth due to the sun’s radio noise, so they are put into a passive state.  The Deep Space Network on the earth can pick up their transmissions, though not well during this period due to its greater sensitivity.

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

Addendum

SOHO LASCO C3 image of the sun

Annotated SOHO LASCO C3 image of the sun, behind the occulting disk with Venus and Mars. Image: ESA, NASA

11/22/2012 – Ephemeris – Celestial navigation in the days of the Pilgrims

November 22, 2012 Comments off

Ephemeris for Thanksgiving Day, Thursday, November 22nd.  The sun will rise at 7:48.  It’ll be up for 9 hours and 19 minutes, setting at 5:08.   The moon, 2 days past first quarter, will set at 2:58 tomorrow morning.

Back in the days of the Pilgrims navigation was much less certain than it is today.  At the mercy of the winds and weather, sailing took a lot of courage.  Celestial navigation took the form of measuring the altitude of the pole star Polaris at night and the sun at noon.  That and tossing a log overboard attached to a rope with knots at regular interval to gauge their speed and progress.  That’s where we get the term knots as a measure of speed for nautical and aviation use.  Today we have GPS to tell us where we are.  However that is based on the position of not stars, but quasars, bright nuclei of distant galaxies, whose motions are currently too small to measure.  Have a happy Thanksgiving.

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

Addendum

 

nasa-map_GPS Quasars

All sky map of quasar locations used as the celestial markers for the GPS system. Chart by David Bobolz, US Naval Observatory.

The chart above is from an article in the Telegraph.