07/24/2015 – Ephemeris – Astronomical viewing opportunities this weekend
Ephemeris for Monday, July 27th. The Sun rises at 6:23. It’ll be up for 14 hours and 51 minutes, setting at 9:14. The Moon, 3 days past first quarter, will set at 3:36 tomorrow morning.
This evening when it gets dark the bright star Deneb in Cygnus the swan will be high in the east northeast. Deneb is the dimmest star of the summer triangle. Of the other stars of the triangle, Vega is very high in the east, while Altair is lower in the southeast. While Deneb’s apparent magnitude, or brightness as seen from earth, makes it the dimmest of the three bright stars, Deneb’s vast distance of possibly 2,600 light years makes it over 100 times the distance of Vega. If brought as close as Vega, Deneb would be almost as bright as the full moon. It is as bright as two hundred thousand suns. It apparently has run out of hydrogen in its core. Once a blue super giant star, it’s currently evolving through the white giant stage.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Betsie Valley District Library star party 2014. A crowd gathers to view Saturn and Jupiter. (Jupiter will be too low this time.) Credit: Betsie Valley District Library staff.
The GTAS at the Sleeping Bear Dunes National Lakeshore’s Platte River Point, April, 2012. This time there will be leaves on the trees. Credit Eileen Carlisle.
07/23/2015 – Ephemeris – Altair, the nearest star of the Summer Triangle
Thursday, July 23rd. Today the Sun will be up for 14 hours and 59 minutes, setting at 9:18. The Moon, 1 day before first quarter, will set at 12:57 tomorrow morning. Tomorrow the Sun will rise at 6:20.
The southernmost star of the Summer Triangle is Altair, high in the south. The other two stars of the triangle are Vega nearly overhead, and Deneb high in the east. Altair is the closest of the three at a distance of 16.7 light years away. One light year is nearly 6 trillion miles. Altair is 10 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. What is rather different about Altair is its rapid rotation. While it’s almost twice the sun’s diameter, it rotates once in only 8.9 hours, The CHARA Interferometer at Mt. Wilson has actually imaged its squashed disk in the infrared. Our sun’s a slow poke, taking nearly a month to rotate once.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle. Created using Stellarium and The Gimp.
Aquila the Eagle in the southeastern sky. Created using Stellarium.
Credit: Zina Deretsky, National Science Foundation
07/22/2015 – Ephemeris – Two planets preparing to leave the evening sky
Ephemeris for Wednesday, July 22nd. Today the Sun will be up for 15 hours and 1 minute, setting at 9:19. The Moon, 2 days before first quarter, will set at 12:28 tomorrow morning. Tomorrow the Sun will rise at 6:18.
Lets take a look at the bright planets for this week. Our evening stars Venus and Jupiter are together in the west by 9:45 p.m. with Jupiter a little above and right of Venus. Venus will set at 10:22 with Jupiter 11 minutes later. Venus’ will slide down to the Sun faster and faster in the coming weeks leaving Jupiter behind for a while. Venus will take 24 days to slide past the Sun. Jupiter though will take 35 days, so Venus will pass it again around August 4th when both are too close to the horizon and Sun to spot. There’s a third conjunction of these two in October in the morning sky with Mars nearby. Saturn is in the south in the evening twilight. It will pass due south at 9:27 p.m. and will set at 2:16 a.m. Even small telescopes can see Saturn’s rings.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus and Jupiter low on the western horizon at 9:45 p.m. on July 22, 2015. Created using Stellarium.
Saturn and the summer zodiacal constellations of Libra, Scorpius and Sagittarius at 10:30 p.m. on July 22, 2015. Created using Stellarium.
The Moon as it might appear in binoculars tonight at 10:30 p.m. (July 22, 2015). Created using Stellarium.
Comparative apparent sizes of the evening planets as seen through a telescope of the same magnification on July 22, 2015. Created using Cartes du Ciel (Sky Charts).
This is a chart showing the sunrise and sunset skies for July 22, 2015 showing the location of the planets at that time. Created using my LookingUp program.
07/21/2015 – Ephemeris – Vega, the brightest star of the Summer Triangle
Ephemeris for Tuesday, July 21st. Today the Sun will be up for 15 hours and 3 minutes, setting at 9:20. The Moon, 3 days before first quarter, will set at 12:01 tomorrow morning. Tomorrow the Sun will rise at 6:17.
The bright star high in the east is Vega, one of the stars of the Summer Triangle an informal constellation called an asterism. Vega belongs to the official constellation Lyra the harp, which includes a narrow parallelogram of stars to its south. Vega was regarded by astronomers as a standard calibration star. Though a first magnitude star, its actual magnitude is 0.03 and slightly variable. It is a type A0 (A-zero) pure white star, and is 25 light years away. Astronomers however got a shock in 1983 when calibrating the Infrared Astronomy Satellite (IRAS) on it: Vega showed an excess of Infrared radiation that means the star is orbited by a disk of dust, perhaps the beginnings of a planetary system. Due to the slow wobble of the earth’s axis Vega will be our pole star in 14 thousand years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle. Created using Stellarium and The Gimp.
Magnified view of Lyra. Created using Stellarium.
Vega in the mid-infrared from the Spitzer Infrared Satellite. Credit: NASA/JPL-Caltech/University of Arizona
07/20/2015 – Ephemeris – July 20th anniversaries
Ephemeris for Monday, July 20th. Today the Sun will be up for 15 hours and 5 minutes, setting at 9:21. The Moon, 4 days before first quarter, will set at 11:34 this evening, and tomorrow the Sun will rise at 6:16.
July 20th is a special date for this country’s space program and a personal one. On July 20, 1969 Apollo 11 landed on the Moon, the greatest achievement in the history of space flight. Seven years later the robot lander Viking 1 landed on Mars. NASA wanted it to be July 4th, 1976, the Bicentennial, but couldn’t find a smooth landing site in time. My own connection to the date came in 1963, my first total solar eclipse. We traveled to Quebec province along side the St. Maurice River. To view 60 seconds of totality. It was the first of four successful total solar eclipse trips I’ve been on.. I’m looking forward to my 5th on August 21st 2017, two years from now which is related to my first, I’ll tell you about that in my blog.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Neil Armstrong about to step off the LM onto the surface of the moon, July 20, 1969. Credit: NASA.
First image sent back from Viking 1 after landing on Mars, July 20, 1976. Credit: NASA/JPL. Click on image to enlarge.
Video of July 20, 1963 eclipse from the air. I got only one picture of the eclipse and it wasn’t very good. https://www.youtube.com/watch?v=OT3EW0KIjCc.
The date on the YouTube page is incorrect. It is July 20, 1963. I remember the corona being somewhat wedge-shaped, wider to one side than the other. Other than that it was a typical quiet sun corona.
In the program above I mentioned that the August 21, 2017 solar eclipse was related to my first total solar eclipse. This is the relationship: A couple of centuries BC the Chaldean astronomers of ancient Babylonia discovered that eclipses repeated in a cycle lasting 6,585 1/3 days. That’s 18 years 10 or 11 and 1/3 days depending on the number of leap years spanned. That period was called the Saros by Sir Edmund Halley or comet fame. So each eclipse would be visible 1/3 of the Earth farther west. Note that there are many Saros cycles occurring at the same time, and that eclipses of a particular Saros gradually move northward or southward. So to have an eclipse recur at the approximate same longitude one must wait 3 Saros cycles. or 54 years and one month approximately. Thus the third Saros of the July 20, 1963 total solar eclipse will be August 21, 2017. This Saros series (145) is moving southward. In 1963 it crosses the US at Alaska and Maine. Quebec was closer for us, s we went there. Good thing too. Maine was clouded and rained out. For us the clouds parted at the beginning of the eclipse. The 2015 eclipse will cross the continental US from Oregon to South Carolina.
A squished image of the July 20, 1963 eclipse path. Right click on the image and select view image to get a correct image. (works in Firefox).
A squished image of the August 21, 2017 eclipse path. Right click on the image and select view image to get a correct image. (works in Firefox).
07/17/2015 – Ephemeris – The constellation of the harp now and Venus and the Moon tomorrow night.
Ephemeris for Friday, July 17th. Today the Sun will be up for 15 hours and 11 minutes, setting at 9:24. The Moon, 2 days past new, will set at 10:07 this evening, and tomorrow the Sun will rise at 6:14.
High in the east at 11 p.m. can be found a bright star just above a small, narrow, but very distinctive parallelogram of stars. They are the stars of the constellation Lyra the harp. The bright star is Vega, one of the twenty one brightest stars, called first magnitude stars. Vega is actually the 5th brightest night time star. The harp, according to Greek mythology, was invented by the god Hermes. The form of the harp in the sky, is as he had invented it: by stretching strings across a tortoise-shell. Hermes gave it to his half-brother Apollo, who in turn gave it to the great musician Orpheus.
Looking westward tomorrow night the planet Venus will appear about 2 moon widths above the crescent Moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Lyra as a tortoise-shell harp. Created using Stellarium and free clip art.
Venus appears above the thin crescent moon with Jupiter to the right at 10 p.m. Saturday July 18, 2015. Created using Stellarium.
07/16/2015 – Ephemeris – The Summer Triangle is the sign of the season
Ephemeris for Thursday, July 16th. Today the Sun will be up for 15 hours and 12 minutes, setting at 9:25. The Moon, 1 day past new, will set at 9:32 this evening, and tomorrow the Sun will rise at 6:13.
We’re almost a month into summer, and the asterism or informal constellation called the Summer Triangle can be seen midway up the sky in the east as it gets dark. Highest of the three bright stars is Vega in the constellation Lyra the harp, whose body is seen in a narrow parallelogram nearby. The second star of the triangle is Deneb lower and left of Vega, It appears dimmer than Vega because it is by far the most distant of the three. The third star of the Summer Triangle is seen farther below and a right of Vega. It is Altair in Aquila the eagle, and the closest. Altair is 16.5 light years away, Vega is 27 light years while Deneb is so far away that it’s distance is in some doubt and may be 2,600 light years away.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Summer Triangle. Created using Stellarium.
07/15/2015 – Ephemeris – Venus and Jupiter are dipping lower in the west
Ephemeris for Wednesday, July 15th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:25. The Moon is new today, and won’t be visible. Tomorrow the Sun will rise at 6:12.
Lets take a look at the bright planets for this week. Our evening stars Venus and Jupiter are still side by side in the west by 9:45 p.m. They both will set near 10:55 p.m.. Venus’ will slide down to the Sun faster and faster in the coming weeks leaving Jupiter behind for a while. Venus will take 1 month to slide past the Sun. Jupiter though will take 6 weeks, so Venus will pass it again around August 4th when both are too close to the horizon and Sun to spot. There’s a third conjunction of these two in October in the morning sky with Mars nearby. Saturn is in the south in the evening twilight. It will pass due south at 9:55 p.m. and will set at 2:44 a.m. Even small telescopes can see Saturn’s rings.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus and Jupiter will be about 9 degrees above the western horizon at 10 p.m. (45 minutes after sunset if you’re not from around here) on July 15, 2015. Created using Stellarium.
Saturn with Scorpius and the Teapot of Sagittarius at 10:30 p.m., July 15, 2015. Created using Stellarium.
Comparative apparent sizes of the evening planets as seen through a telescope of the same magnification. Created using Cartes du Ciel (Sky Charts).
This is a chart adapted from the one I publish monthly as my role as the editor of the Grand Traverse Astronomical Society newsletter the Stellar Sentinel. It’s for sunrise and sunset for July 15, 2015 showing the location of the planets at that time. I’m bringing it to Wednesday Planet Day on this blog. Created using my LookingUp program. Click on the image to enlarge.
07/14/2015 – Ephemeris – New Horizons is beginning its encounter with Pluto right now
Ephemeris for Tuesday, July 14th. Today the Sun will be up for 15 hours and 16 minutes, setting at 9:26. The Moon, 1 day before new, will rise at 6:01 tomorrow morning, and tomorrow the Sun will rise at 6:11.
Right now as I speak the New Horizons spacecraft is beginning its pass through the Pluto system of the dwarf planet itself, its huge moon Charon and four smaller moons. It’s nail-biting time, because the spacecraft will be too busy to send anything back immediately. Everything will be stored for playback over the next 16 months. We will expect to hear from it at 9:02 tonight when a brief phone home signal will be sent to confirm the probe’s survival. Already this morning 7 of NASA’s deep space network antennas will have blasted a radio signal to Pluto* in time for the spacecraft to receive the signal as it passes behind first Pluto and Charon to probe their atmospheres. Tomorrow we will expect to receive the first closeup images.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
*I’ve since found out that the signal will be broadcast from those antennas from 4:30 to 6:30 a.m. EDT, Check with DSN Now: http://eyes.nasa.gov/dsn/dsn.html. DSN Now shows all the antennas of all the DSN sites. Those antennas transmitting or receive data from New Horizons will have the label NHPC.
Addendum
Last image of Pluto posted before the encounter. Note that the “Heart” is rotating into view on the left. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Click on image to enlarge.
07/13/2015 – Ephemeris – New Horizons’ encounter with Pluto just 1 day to go!
Ephemeris for Monday, July 13th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:27. The Moon, 2 days before new, will rise at 5:05 tomorrow morning, and tomorrow the Sun will rise at 6:10.
The New Horizons spacecraft is hopefully Go for its encounter with Pluto and its moons tomorrow morning (July 14, 2015), and tomorrow New Horizons will be working in radio silence because it will be too busy to turn and relay anything to the Earth. Tomorrow evening we should get a signal from the spacecraft with engineering data on its survival of the encounter. Any photographs will be sent starting Wednesday. Pretty pictures are not the only data to be sent back. It will take 16 months to get all the data sent back. A series of highly compressed images will be sent for the next 6 days. Then other data will be taking priority until September 14th when photographs will again be sent. We’ll be feasting on the information for quite some time.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The following images are shown in chronological order as New Horizons approaches Pluto and Charon. Click on any of these images to enlarge.
Pluto on three consecutive days: July 2-3 as the Pluto rotates not quite half a rotation. It’s rotation period is 6.4 Earth-days. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
On July 4, the spacecraft went into safe mode. Imaging resumed on July 8th.
Pluto on July 8th showing its love for us, or it’s just a heart-shaped feature on Pluto’s lower right edge. This is a back & white image colorized by information captured by “Ralph”, a visible and infrared imager. The detail in all these pictures is provided by LORRI the long-range imager. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
An annotated image from July 10. The rest of the “whale” can be seen impinging on the “heart” in the July 8 image. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
Pluto on July 11. Note the four mysterious dark spots along the bottom right of the disk. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
Pluto image annotated for July 12 (2 days before encounter). The features on the right are intriguing, but we’ll have to wait for the next mission to resolve. New Horizons can’t stop. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
The moon Charon on July 12 with some of its features noted. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
