10/31/2014 – Ephemeris – The spookiest star

October 31, 2014 Leave a comment

Ephemeris for Halloween, Friday, October 31st.  The sun will rise at 8:18.  It’ll be up for 10 hours and 13 minutes, setting at 6:32.   The moon, 1 day past first quarter, will set at 1:59 tomorrow morning.

Not all the ghosts and goblins out Sunday will be children.  One will be out every night, because it’s a star.  Its name is Algol, from the Arabic for Ghoul Star or Demon Star.  The Chinese had a name for it that meant “piled up corpses”.  It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening.  The star is located where artists have drawn the severed head of Medusa, whom he had slain.  Medusa was so ugly that she turned all who gazed upon her to stone.  Algol is her still glittering eye.  Astronomers finally found out what was wrong with Algol.  It does a slow 6 hour wink every two days 21 hours, because it is two stars that eclipse each other.  Her next wink will be 10 p.m. Sunday night.

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

Addendum

Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius.

Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius. Image found with the article on Algol in Wikipedia.

Celestial globes of the day showed the celestial sphere from the outside, so the constellations appeared reversed.  The star atlases of the day kept the trend.  I reversed the image to correspond with the actual sky.

Algol at 7:30 p.m. on Halloween

Algol at 7:30 p.m. on Halloween, in a modern portrayal.  Created using Stellarium.

Update

Eclipsing Binary Star

Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons.  H/T EarthSky

Here’s a link to EarthSky’s post on Algol.

10/30/2014 – Ephemeris – Previewing November’s skies

October 30, 2014 Leave a comment

Ephemeris for Thursday, October 30th.  The sun will rise at 8:17.  It’ll be up for 10 hours and 16 minutes, setting at 6:34.   The moon, at first quarter today, will set at 12:49 tomorrow morning.

Let’s look at the skies for the month of November a couple of days early. The sun is still moving south rapidly.  Daylight hours in the Interlochen/Traverse City area and will drop from 10 hours and 11 minutes i\on the 1st  to 9 hours 6 minutes on the 30th.  The altitude, or angle, of the sun above the southern horizon at local noon will be just under 31 degrees Saturday and will descend to 23 and a half degrees on the 30th.  The altitude of the sun in the Straits area will be a degree lower.  Local noon, this month, will be about 12:30 p.m. when we go back to standard time this weekend.   The Leonid meteors have two possible dates this month, the 17th and the 21st.  Those on the 21st seem to be best timed for our location on the Earth.

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

Addendum

Star Chart t for November 2014

Star Chart for November 2014. Created using my LookingUp program. Created using my LookingUp program.

The Moon is not plotted.  The planets and stars are plotted for the 15th at 9 p.m.  That is chart time.

Astronomical twilight ends at 7:08 p.m. on November 2nd, decreasing to 6:48 on the 31st.

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.

Also shown is the Summer Triangle in red. Clockwise from the top star is Deneb in Cygnus, Vega in  Lyra and Altair in Aquila.

The green pointers from the Big Dipper are:

  • Pointer stars at the front of the bowl of the Big Dipper point to Polaris the North Star.

10/29/2014 – Ephemeris – A last look at the bright planets for October

October 29, 2014 Leave a comment

Ephemeris for Wednesday, October 29th.  The sun will rise at 8:16.  It’ll be up for 10 hours and 19 minutes, setting at 6:35.   The moon, 1 day before first quarter, will set at 11:41 this evening.

Tonight Mars will be low in the southwest at 8 p.m. below and right of the Moon in the constellation of Sagittarius, and will set at 9:35 p.m.  The sky will stay devoid of bright planets until Jupiter rises at 1:33 a.m.  Jupiter is visible this morning in twilight in the south-southeast along with the brighter stars of winter, a preview of colder evenings to come.  The planet Mercury makes its autumn morning appearance for the next week or so, rising in the east-southeast at 6:38.  By 7:20 or so it should be visible low in the sky.  It’s greatest western elongation will be this Saturday, and it will pass perihelion, its closest to the Sun, this Sunday, so despite its greatest elongation, it’s less than a 19 degree angle from the Sun.

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

Ephemeris

Mars and the setting summer stars

Mars, the Moon and the setting stars of summer at 8 p.m. on October 29, 2014. Created using Stellarium.

The Moon

The Moon as it would appear in binoculars at 8 p.m. October 29, 2014. Created using Stellarium.

Morning planets

The morning planets and constellations at 7:30 a.m. October 30, 2014. Created using Stellarium.

Jupiter and its moons as seen in a telescope at 7:30 a.m. October 30, 2014.  Io is behind Jupiter.  Created using Stellarium.

Jupiter and its moons as seen in a telescope at 7:30 a.m. October 30, 2014. Io is behind Jupiter. Created using Stellarium.

10/28/2014 – Ephemeris – The Pleiades Distance Controversy

October 28, 2014 Leave a comment

Ephemeris for Tuesday, October 28th.  The sun will rise at 8:14.  It’ll be up for 10 hours and 22 minutes, setting at 6:37.   The moon, 2 days before first quarter, will set at 10:37 this evening.

Yesterday we looked at the Pleiades or Seven Sisters star cluster.  The Pleiades is nearby.  For a long time the Pleiades distance was calculated to be about 435 light years.  It was beyond the distance that could be determined from the Earth by triangulation or parallax.  In the early 1990s the European Space Agency satellite Hipparcos was launched to improve and extend the parallax measurement of nearby stars.  However the distance determined to the Pleiades was 392 light years, 90 percent of the previous value.  A lot of what we have determined about stars and their evolution was based on the original distance to the Pleiades.  It meant that the Pleiades stars were  dimmer than first calculated, affecting our ideas of stellar evolution.  Many astronomers were wary of the supposed more accurate Hipparcos result.  However recently using a network of radio telescopes that span the diameter of the Earth in a Very Long Base Interferometry Array, a new distance was determined, a more agreeable 444 light years.

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

Addendum

The Pleiades, about what you'd see in binoculars.

The Pleiades, about what you’d see in binoculars.

vlbi_array

10/27/2014 – Ephemeris – The Pleiades in Greek and Native American mythology

October 27, 2014 Leave a comment

Ephemeris for Monday, October 27th.  The sun will rise at 8:13.  It’ll be up for 10 hours and 25 minutes, setting at 6:38.   The moon, 3 days before first quarter, will set at 9:38 this evening.

Visible low in the east at 10 in the evening sky can be spotted a small group of stars.  It’s called the Pleiades or Seven Sisters.  The Pleiades are really spectacular when seen in binoculars.  It is remarkable that both the Greeks and the American Plains Indians saw this group as female stars fleeing from danger.  In the former case they were fleeing the constellation Orion the giant hunter of the winter sky who will soon rise over the eastern horizon, and in the latter case a giant bear.  Legend has it that the maidens fled to the top of Devils Tower in Wyoming.  It’s said that the claw marks of this bear are seen in the walls of the tower.  The maidens were then spirited from the top of the tower to the heavens, where we see them today.  Whichever story you like the Pleiades is worth searching for.

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

Addendum

The Pleiades, about what you'd see in binoculars.

The Pleiades, about what you’d see in binoculars.

Pleiades finder chart

Looking to the east northeast at the Pleiades: 9 p.m. on October 27th. Created using Stellarium,

Greek Pleiades

The Greek Pleiades a painting by Elihu Vedder in the Metropolitan Museum of Art, New York City. Public Domain.

Legend of Devils Tower Credit: Indian Country Today Media Network

This is the illustration from http://indiancountrytodaymedianetwork.com/article/the-legend-of-devils-tower-3273

10/24/2014 -Ephemeris – Venus will pass superior conjunction with the Sun tomorrow

October 24, 2014 Comments off

Ephemeris for Friday, October 24th.  The sun will rise at 8:09.  It’ll be up for 10 hours and 33 minutes, setting at 6:43.   The moon, 1 day past new, will set at 7:20 this evening.

Tomorrow’s event will not be visible.  Venus will pass behind the Sun, though not directly behind it.  Venus can be viewed from the SOHO spacecraft go to http://spaceweather.com/, at the bottom click the link for Solar and Heliospheric Observatory, Click on the Sun Now, then LASCO C2.  The event is called a superior conjunction, meaning the Venus is beyond the Sun.  It will be moving from west of the Sun to the east, from the morning side of the Sun to the evening side.  Venus has been in the morning sky since January 11th.  So it is a morning planet for about 9 months and moves to the evening sky for another 9 months.  In a month or so, Venus will appear low in the southwestern sky shortly after sunset.  It will be our super bright evening star next spring.

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

Addendum

LASCO C2

Venus approaching superior conjunction 10/20/2014 to 10/23/2014. Credit NASA – SOHO LASCO C2.

10/23/2014 – Ephemeris – Partial solar eclipse tonight for most of the US

October 23, 2014 Comments off

Ephemeris for Thursday, October 23rd.  The sun will rise at 8:08.  It’ll be up for 10 hours and 36 minutes, setting at 6:44.  The moon is new today, and won’t be visible.

This evening there will be a partial solar eclipse, in which we will see only the first part before the sun sets.  The eclipse will be visible for all but the extreme eastern part of the country.  It will be a partial eclipse for all who can see it because the core of the Moon’s shadow will miss the Earth to the north.  For the Interlochen Public Radio listening area (Northwestern Lower Michigan) the eclipse will star a couple of minutes before or after 5:32 p.m. and will end at sunset around 6:44 p.m.  The low position of the sun make a lack of cloud cover necessary to be able to see it.  Proper approved solar filters, or a projection method are necessary to view the eclipse.  Do Not Look Directly at the Sun!  The NMC Observatory south of Traverse City will be open, weather permitting starting at 5 p.m.  Also the Platte River Point location at the Sleeping Bear Dunes National Lakeshore will also be available.

An added attraction for this eclipse is the appearance of the largest sunspot group to appear on the sun in years.

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

Addendum

Solar Eclipse coverage

Coverage of the partial solar eclipse of October 23, 2014. Credit: NASA.

Setting partially eclipsed sun

The setting partially eclipsed sun from Traverse City. Created using Stellarium.

Pinhole projection

Partially eclipsed sun using a series of pinholes projected on a reasonably white surface.

Big Sunspot

The Sun at 1:30 a.m. 10/23/2014 with large sunspot group AR 2192. Credit NASA – Solar Dynamics Observatory.

This baby gave off a X Class flare yesterday (10/22/2014).  Could be more in store.  Maybe we’ll see an aurora later this week.

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