07/24/2014 – Ephemeris – A look at Altair the third star of the Summer Triangle

July 24, 2014 Leave a comment

Ephemeris for Thursday, July 24th.  The sun rises at 6:20.  It’ll be up for 14 hours and 56 minutes, setting at 9:17.   The moon, 2 days before new, will rise at 5:21 tomorrow morning.

The Summer Triangle Is high in the east to southeast sky in the evening. The southernmost star of the Summer Triangle is Altair, in the southeast.  Altair is the closest of the three stars at a distance of 16.7 light years away. One light year is nearly 6 trillion miles, that’s 6 followed by 12 zeros. Altair is nearly 11 times the brightness of the sun. If seen at Altair’s distance, the sun would only be as bright as one of the two stars that flank it in our sky. What is rather different about Altair is its rapid rotation. While it’s almost twice the sun’s diameter, it rotates once in only 9 hours, and would show a decidedly squashed appearance if seen close up. Our sun’s a slow poke, taking nearly a month to rotate just once.

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

Addendum

The constellations Lyra, Cygnus and Aquila

Deneb with the other stars and constellations in the Summer Triangle. Created using Stellarium.

Oblate Altair

False-color image of the rapidly rotating star Altair, made with the MIRC imager on the CHARA array on Mt. Wilson. Credit: Ming Zhao, University of Michigan

07/23/2014 – Ephemeris – It’s Wednesday. Do you know where the bright planets are?

July 23, 2014 Leave a comment

Ephemeris for Wednesday, July 23rd.  The sun rises at 6:19.  It’ll be up for 14 hours and 58 minutes, setting at 9:18.   The moon, 3 days before new, will rise at 4:28 tomorrow morning.

It’s Wednesday and once again time to locate the bright planets for this week.  Reddish Mars is in Virgo in the southwest as darkness falls.  It’s 105 million miles (169 million km) away now, nearly 3 times farther away than it was last April, and will set at 12:39 a.m.  Saturn will be low in the south-southwest as darkness falls, in the faint constellation of Libra the scales.  It will set at 1:38 a.m.  Saturn’s in perfect position for viewing with a small or large telescopes to see those fabulous rings and its large moon Titan.  Somewhat larger telescopes can spot some smaller moons closer in.  Brilliant Venus will rise in the east at 4:22 a.m. in morning twilight.  Mercury will rise at 4:46 and be barely visible below Venus.  The crescent moon will be right of Venus tomorrow morning.

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

Addendum

Evening planets

The evening planets Mars and Saturn with the zodiacal constellations at 10:30 p.m. on July 23, 2014. Created using Stellarium.

Saturn

Saturn through a telescope. In small telescopes of the moons only Titan will be visible. July 23, 2014. Created using Stellarium.

 

Morning Planets

Venus, Mercury, and the crescent Moon at 5:30 a.m. on July 24, 2014. Created using Stellarium.

07/22/2014 – Ephemeris – Rosetta spies a cosmic rubber ducky

July 22, 2014 Leave a comment

Ephemeris for Tuesday, July 22nd.  Today the sun will be up for 15 hours even, setting at 9:18.   The moon, half way from last quarter to new, will rise at 3:38 tomorrow morning.  Tomorrow the sun will rise at 6:19.

The European Space Agency (ESA) Rosetta spacecraft is closing in on Comet 67P/Churyumov-Gerasimenko, also known as Comet Cherry-Gerry, or Comet C-G.  After photos of the comet’s nucleus were published last week it has acquired a new nickname: Rubber Ducky.  The nucleus may be a contact binary with two comet nuclei that stuck together after a slow speed collision.  Further study may reveal the nature of the two pieces.  Rosetta has more than a year to study the comet.  It has a lander craft called Philae that can land on one of the pieces of the nucleus.  No one expected the possibility of two possibly dissimilar comet nuclei to study.  Rosetta will enter orbit of the comet August 6th.

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

Addendum

July 4, images

A hint of strangeness appears on July 4, 2014. What’s that lump on the side in that third image? Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

July 14th animation

An animation of Comet C-G rotation on July 14, 2014. The 30 pixel wide image has been smoothed. The actual rotation rate is 1 rotation every 12.4 hours. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

For more information go to http://sci.esa.int/rosetta/, or search: esa rosetta.

The post that explains this image more fully is here.

ESA has a policy of weekly releases, so expect a new one this Wednesday, Thursday or Friday.

 

 

07/21/2014 – Ephemeris – The celestial eagle: Aquila

July 21, 2014 1 comment

Ephemeris for Monday, July 21st.  Today the sun will be up for 15 hours and 2 minutes, setting at 9:19.   The moon, 3 days past last quarter, will rise at 2:52 tomorrow morning.  Tomorrow the sun will rise at 6:18.

Aquila the eagle is a constellation that lies in the Milky Way.  It’s in the southeastern sky as it gets dark.  Its brightest star, Altair is one of the stars of the Summer Triangle, a group of three bright stars dominating the eastern sky in the evening now.  Altair, in the head of the eagle, is flanked by two slightly dimmer stars, the shoulders of the eagle.  The eagle is flying northeastward through the Milky Way.  Its wings are seen in the wing tip stars. A curved group of stars to the lower right of Altair is its tail.  Within Aquila the Milky Way shows many dark clouds as part of the Great Rift that splits it here.  The other summer bird is Cygnus the swan above and left of Aquila, flying in the opposite direction.

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

Addendum

The constellations Lyra, Cygnus and Aquila

Deneb with the other stars and constellations in the Summer Triangle. Created using Stellarium.

07/18/2014 – Ephemeris – Deneb is the brightest star of the Summer Triangle… Really

July 18, 2014 Comments off

Ephemeris for Friday, July 18th.  Today the sun will be up for 15 hours and 8 minutes, setting at 9:22.   The moon, at last quarter today, will rise at 12:58 tomorrow morning.  Tomorrow the sun will rise at 6:15.

At 11 this evening the bright star Deneb in Cygnus the swan will be moderately high in the east northeast.  Deneb is the dimmest star of the summer triangle.  Of the other stars of the triangle, Vega is nearly overhead, and Altair to the southeast.  While Deneb’s apparent magnitude, or brightness as seen from Earth, makes it the dimmest of the three bright stars, Deneb has a vast distance of possibly 1,550  light years.  If brought as close as Vega, Deneb would be several times brighter than Venus.  For all this it is only 13-20 times the mass of the sun.  It will have an extremely short life and will explode, go supernova, in perhaps a few million years.  Closer to home, check out the Sun at Kingsley Heritage Days This Saturday and Sunday.

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

Addendum

Northern Cross

Deneb and the Northern Cross section of Cygnus the swan. Created using Stellarium.

Deneb & North American Nebula

One of my old photographs of Deneb and the North American Nebula digitized from a slide.

The North American Nebula, visible as a faint smudge in binoculars or the naked eye may be ionized and illuminated by Deneb.  It’s distance appears to be comparable to that of Deneb.

You may note that previous postings about Deneb over the years have given different distances of Deneb.  That just denotes how difficult it is to pin down its distance.

07/17/2014 – Ephemeris – The constellation Cygnus the swan

July 17, 2014 Comments off

Ephemeris for Thursday, July 17th.  Today the sun will be up for 15 hours and 10 minutes, setting at 9:23.   The moon, 1 day before last quarter, will rise at 12:25 tomorrow morning.  Tomorrow the sun will rise at 6:14.  |  Fairly high in the east at 11 p.m. Is the constellation of Cygnus the swan, flying south through the Milky Way.  It is also called the Northern Cross.  At the left, the tail of the swan or the head of the cross is the bright star Deneb, one of the stars of the Summer Triangle.  The next star right is Sadr the intersection of the body and the wings of the swan seen in flight, or the intersection of the two pieces of the cross.  There are two or three stars farther to the right that delineate the swan’s long neck or upright of the cross, that ends with the star Alberio in the beak of the swan or foot of the cross.  The crosspiece of the cross extends to the stars on either side of the intersection star Sadr, while the swan’s wings extend to a couple more stars each.

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

Addendum

CygnusTheSwan Created using Stellarium.

CygnusTheSwan Created using Stellarium.

07/16/2014 – Ephemeris – A late post for the planet day

July 17, 2014 Comments off

Ephemeris for Wednesday, July 16th.  Today the sun will be up for 15 hours and 11 minutes, setting at 9:24.   The moon, 2 days before last quarter, will rise at 11:52 this evening.  Tomorrow the sun will rise at 6:13.

It’s Wednesday and once again time to locate the bright planets for this week.  Reddish Mars is in Virgo in the southwest as darkness falls.  It’s 101 million miles (163 million km) away now, nearly 2 and a half times farther away than last April, and will set at 12:56 a.m.  Saturn will be low in the south-southwest as darkness falls, in the faint constellation of Libra the scales.  It will set at 2:06 a.m.  Saturn’s in perfect position for viewing with a small or large telescopes to see those fabulous rings and its large moon Titan.  Somewhat larger telescopes can spot some smaller moons closer in.  Brilliant Venus will rise in the east at 4:14 a.m. in morning twilight.  Mercury will rise at 4:46 and be barely visible below Venus.

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

Addendum

I’m late on this one, so the planet positions below are for Thursday evening and Friday Morning.

Mars and Saturn

Mars and Saturn with the evening stars and constellations at 11 p.m. Thursday July 17, 2014. Created using Stellarium.

Saturn

Saturn through a telescope. In small telescopes of the moons only Titan will be visible. July 17, 2014. Created using Stellarium.

Venus & Mercury

Venus and Mercury at 5:30 a.m. July 18, 2014. Created using Stellarium.

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