Skywatch Line for Friday, July 21, through Sunday, July 23, 2017

This is Dudley Observatory’s Skywatch Line for Friday, July 21, through Sunday, July 23, written by Sam Salem.

On Friday, Sun rises at 5:36am and sets at 8:27pm; Moon rises at 3:43am and sets at 6:50pm. New Moon occurs on Sunday at 5:46am. Mercury is higher in the evening twilight this weekend. Its greatest elongation from the Sun occurs on July 25. Jupiter shines at magnitude –1.9 high up in the west-southwest as darkness falls. At magnitude 0.2, Saturn is still an easy find low down in southern of constellation Ophiuchus. The best time to see Saturn in a telescope is when it reaches the meridian at around 11pm. Venus clears the east-northeast horizon at magnitude –4.1 around 2:42am on Friday.

Use the Summer Triangle asterism 1st-magnitude stars Vega, Altair, and Deneb to point you to the Teapot of Sagittarius and the Galactic center. Gaze southward once it gets dark to find “The Teapot” which marks the general direction of the Galactic center so heavily veiled by intervening stars, star clusters and nebulae. The Teapot makes up the western half of the constellation Sagittarius, the Archer. Draw an imaginary line from Deneb through Altair to star-hop to the Teapot of Sagittarius. This year the Milky Way center lies about midway between the spout of the Teapot and the planet Saturn. Use Saturn to guide you to the Teapot and the Galactic center.

The Teapot of Sagittarius sits below constellation Scutum, the Shield, and the bright star Vega shines high above it. Scutum is located in a rich region of the Milky Way and requires a dark sky to be seen. Look southward late in the evening toward the richest part of the Milky Way to find the very small constellation Scutum. It has only four stars that make up the constellation outline. The Polish astronomer Johannes Hevelius named it Scutum Sobiescianum, meaning the shield of Sobieski, in 1683. He named it for Jan III Sobieski, a Polish king who led his armies to victory in the Battle of Vienna. Scutum is one of two constellations named after real people. The other one is Coma Berenices, named for an Egyptian queen.

On these July evenings, look high overhead for Corona Borealis, or the Northern Crown. The semi-circle of stars lies between the two bright stars Arcturus and Vega. Arcturus reaches transit altitude of 66 degrees south almost an hour before sunset and it sets around 2:30am. Vega is still high in the east on July evenings. Vega reaches transit altitude of 68 degrees south around 11:30pm. Corona Borealis constellation is easy to pick out in a dark sky. It makes the shape of the letter C in the middle of which is a white jewel of a star called Alphecca or Gemma. Gemma is a Latin name, which means a “gem”. The gem of the Northern Crown is also called Alphecca, from an Arabic phrase meaning “the bright one of the dish”. Gemma, or Alphecca, is an eclipsing binary system. It consists of a smaller star that passes in front of a brighter star every 17.4 days, as seen from earth.


Skywatch Line for Wednesday, July 19th, and Thursday, July 20th, 2017

This is the Dudley Observatory Skywatch Line for Wednesday, July 19th, and Thursday, July 20th, written by Louis Suarato.

As our region on Earth turns away from the Sun, and the sky darkens, look for three planets to appear. First look low over the west-northwestern horizon for Mercury before it sets at 9:41 p.m. below the constellation Leo. The European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) have recently announced a joint effort to send a probe to Mercury to look for clues as to why the solar system’s smallest planet is apparently getting smaller. The spacecraft, the BepiColombo, is expected to be launched next year, and settle into orbit around Mercury in 2025. Once in orbit, the BepiColombo must survive temperatures ranging from -280 degrees Fahrenheit to 800 degrees Fahrenheit.

Next, look for Saturn about 20 degrees over the south-southwestern horizon in the constellation Ophiuchus. Wednesday, the Cassini spacecraft is scheduled to perform distant flybys of Saturn’s innermost moons Janus and Atlas. Atlas is the closest satellite to Saturn’s A ring. Janus orbits Saturn with the satellite Epimetheus. Janus and Epimetheus are the only two moons in the solar system that switch orbits. The inner moon gains an additional 0.25 degree on the outer moon each day. As the two moons close, the inner moon gains velocity, while the outer moon slows. This momentum exchange causes the two moons to swap orbits. This occurs every four years.

Last, look for Jupiter about 25 degrees above the southwestern horizon in the constellation Virgo. The Juno spacecraft just completed its flyby of Jupiter’s Great Red Spot. Look on-line for the spectacular images sent back to Earth from Juno. Wednesday night, beginning at 9:21 p.m., Jupiter’s moon Io begins its transit across the face of the planet. Io’s shadow begins its transit at 10:36 p.m., followed by the Great Red Spot a half hour later.

Thursday morning features a close conjunction of the crescent Moon and Venus. Venus rises in Taurus at 2:45 a.m. followed by the 11% illuminated, waning crescent Moon 9 minutes later. The Moon and Venus will be 3 degrees apart.
The Albany Area Amateur Astronomers invite you to join them for their monthly meeting Thursday, July 20 at 7:30 p.m. at the miSci in Schenectady. This month’s speaker is professor Francis Wilkin, Observatory Manager and Lecturer of Physics and Astronomy at Union College and University. Professor Wilkin will discuss the discoveries of LIGO, the Laser Interferometer Gravitational-Wave Observatory.

Skywatch Line for Monday and Tuesday, July 17th and 18th, 2017

This is the Skywatch Line for Monday and Tuesday, July 17th and 18th.

The Sun sets at 8:30 PM; night falls at 10:36. Dawn breaks at 3:27 AM and ends with sunrise at 5:33.

Evening has three moderately bright planets in the western half of the sky. Mercury is bright at zero magnitude, low in the West. Six degrees above the horizon, it is small at 6 arc-seconds in size, and appears about 64 percent illuminated. Binoculars may help find it amid the Sun’s glare. Mercury sets at 9:44 PM.

Giant planets Jupiter and Saturn occupy the central evening sky. Jupiter, in Virgo, blazes at minus 2nd magnitude, is 36 arc-seconds in size, is about 28 degrees high in the southwest and 9 degrees above the bright star Spica. It sets at 11:54 PM.

Saturn inhabits Ophiuchus, also moderately high in the South, shining at zero magnitude and appearing 18 arc-seconds in size. Saturn is about as low in the sky as it can get, but still provides views of its ring system to binocular and telescopic observers. Saturn is about 13 degrees to the star Antares’ upper left. It is best observed at about 11:54 PM and sets at 3:13 AM.

Neptune rises in Aquarius at 10:37 PM and appears as a tiny blue-green dot of 8th magnitude. Best sighted at 4:12 AM, it can be found about 2 degrees left of the star Hydor, also called Lambda Aquarii. Uranus, in Pisces, rises about 12:15 AM also appearing as a tiny, but slightly brighter, blue-green dot. Both planets require detailed finder charts found in astronomy magazines and apps.

The 24-day-old Moon rises in Aries at 1:22 AM Tuesday, blazes at minus 8th magnitude and appears about a third illuminated. Wednesday morning, it rises in Taurus at 2:02 AM and appears about 23 percent lit.

Venus, also in Taurus, rises about 2:41 AM, glares at minus 4th magnitude and appears about 70 percent lit.

Tuesday marks a sad 20th anniversary; Eugene (Gene) Shoemaker, geologist-turned-astronomy-pioneer, died. He, as a child, became interested in geology at the Buffalo (NY) Museum, and became a prodigy, enrolled at Caltech at the age of 16. Gene was hired by the US Geological Survey and first tasked with finding uranium deposits and later studying volcanic processes. He also examined nuclear weapons tests and their resulting craters. He realized that Arizona’s Barringer Crater was a nuclear-type crater writ large and proved it was a meteor strike. Shoemaker became involved in the Ranger probes of the Moon and, at one time, was considered for the role of geologist on an Apollo mission. Sidelined by a medical condition, he trained Jack Schmitt to do the geology on Apollo 17. Research proved that lunar craters were mostly due to asteroid impacts, contrary to prevailing theory that they were old volcanoes. In 1969, he and his wife Caroline began a systematic search for Earth crossing asteroids, discovering families of asteroids. In 1993, as part of the asteroid search, Gene, Caroline and astronomer David Levy, discovered Comet Shoemaker-Levy 9. Jupiter’s impact “scars” could be seen through backyard telescopes. He died in Australia while hunting impact craters.

Skywatch Line for Friday, July 14, through Sunday, July 16, 2017

This is Dudley Observatory’s Skywatch Line for Friday, July 14, through Sunday, July 16, written by Sam Salem.

On Friday, Sun rises at 5:30am and sets at 8:33pm; Moon sets at 11:44pm. Last quarter Moon occurs on Sunday at 3:26pm but doesn’t rise until after 1:00am on Monday.

Mercury hangs very low in the west in bright twilight at magnitude –0.3. The fast-moving little planet will climb higher in the coming weeks. Jupiter at magnitude –2.0 is well past the meridian at sunset. Saturn doesn’t culminate until around 11:15pm. At magnitude 0.1, Saturn is easy to identify low in the south, almost 14 degrees east of first-magnitude Antares. Venus, at magnitude –4.1, rises in the east at dawn. The “morning star” rises around 3am and climbs to an altitude of almost 25 degrees by sunrise. Venus is 3 degrees upper left of Aldebaran on Friday morning.

Try to locate the faint constellation Ophiuchus, the Serpent Bearer. Look southward at mid-to-late evening. Ophiuchus is sometimes called the 13th or forgotten constellation of the zodiac. The Sun passes in front of Ophiuchus from about November 29 to December 17. However, Ophiuchus is a constellation, not a sign of the zodiac. The 12 signs of the tropical zodiac represent equal 30- degree divisions of sky. Saturn and the bright star Antares in the constellation Scorpius, the Scorpion, can help you find Ophiuchus in the night sky. Saturn shines in front of Ophiuchus this year. Find Ophiuchus to the north of Antares.

Take advantage of the moonless evenings this weekend to do some deep-sky observing. Constellations Sagittarius and Ophiuchus harbor seven globular clusters each, which is nearly half the total in the entire Messier catalogue. M22, in Sagittarius, is an interesting cluster in any size telescope. The glowing M22, at magnitude 5.1, is the brightest Messier globular. It can be easily spotted in 10×50 binoculars. Find M22 about 2.5 degrees northeast of Lambda (λ) Sagittarii, the star marking the top of the Sagittarius Teapot.

The Great Rift of Milky Way passes through the constellation Cassiopeia and the Summer Triangle, between the stars Vega and Altair. The Great Rift is a series of overlapping, non-luminous, molecular dust clouds that are located between the Solar System and the Sagittarius Arm of the Milky Way Galaxy. To the naked eye, the Great Rift appears as a dark lane that divides the bright band of the Milky Way lengthwise, through about one-third of its extent, and is bordered by lanes of numerous stars. Starting at the constellation of Cygnus, where it is known as the Cygnus Rift, the Great Rift stretches to Aquila, to Ophiuchus, where it broadens out, to Sagittarius, where it obscures the Galactic Center, and finally, to Centaurus.

Saturday marks the 74th birthday of British astronomer, Jocelyn Bell Burnell who discovered the first four pulsars. Jocelyn was a Cambridge University graduate student searching for quasars in 1967, when she noticed an unusual stellar radio signal with a rapid series of pulses repeating every 1.337 sec. In the next few months, she found three more sources of radio pulses. The interstellar signals were not man-made. Therefore, the signals were nicknamed LGM (Little Green Men). These signals were emitted by a new class of celestial objects, Pulsars, which astronomers associated with superdense matter in the final stage of the evolution of massive stars.

Skywatch Line for Wednesday, July 12th and Thursday, July 13th, 2017

This is the Dudley Observatory Skywatch Line for Wednesday, July 12th and Thursday, July 13th written by Louis Suarato.

The 86% illuminated, waning gibbous Moon rises in the constellation Aquarius at 10:41 p.m. Wednesday. After sunset, look for Saturn above the south-southeastern horizon, and Jupiter above the southwestern horizon. Wednesday night, beginning at 9:48 p.m., Jupiter’s moon Europa will be occulted by the planet. Jupiter will set before you have the opportunity to view Europa emerge from behind the planet. Venus rises in Taurus at 2:45 a.m., 2 degrees from the star Aldebaran. Aldebaran, the brightest star in Taurus, and fourteenth brightest in the sky, is a red giant located 65 light-years away. The collapse of Aldebaran’s core has caused its shell to expand to 44.2 times the diameter of the Sun. The candidate for the largest star, UY Scuti, is estimated to have a radius that is 1,708 times that of our Sun. If UY Scuti were at the center of our solar system, its outer shell would extend beyond Jupiter, approximately 500 million miles away. Look 10 degrees above Venus for the Pleiades star cluster. Look higher, almost to the zenith at 84 degrees, for the Andromeda Galaxy.

The solar cycle is an approximately eleven year period when the number of sunspots increase during solar maximum, and decline during solar minimum. The current solar cycle, cycle 24, began on January 4, 2008. After peaking in 2013 and 2014, sunspot activity has been steadily declining. After many days of a spotless Sun, sunspot AR2665 has appeared and is growing as it crosses the face of the Sun. Sunspots are cooler areas on the surface of the Sun that indicate tremendous energy brewing below. At temperatures exceeding 6,000 degrees Fahrenheit, sunspots are about 3,000 degrees less than the temperature of the Sun. Sunspot AR2665 is located close to the Sun’s equator, an indication the solar cycle is ending. Take out that solar viewing equipment you have for August 21’s solar eclipse, and test it by viewing this sunspot.

Early Thursday morning, as Venus is rising, a bright -3.4 magnitude International Space Station will emerge to the left of Cassiopeia in the northeast, and continue on toward Capella in Auriga, before passing the rising Venice.

Skywatch Line for Monday and Tuesday, July 10th and 11th, 2017

This is the Skywatch Line for Monday and Tuesday, July 10th and 11th.

The Sun sets at 8:34 PM; night falls at 10:45. Dawn begins at 3:16 AM and ends with the Sun rising at 5:27.

Jupiter is the brightest object in the early evening sky. It is high in the southwestern sky, and shines at minus 2nd magnitude. It lies about 10 degrees to the right of Virgo’s brightest star, Spica. Jupiter sets after Midnight.

Saturn is moderately high in the South, shining at zero magnitude. It is best observed at about 11 PM and sets at 3:42 AM.

Mercury also shines at zero magnitude, but is quite low on the western sky, about 20 degrees to the lower right of Leo’s brightest star, Regulus. In low power telescopes or binoculars, it appears about 75 percent illuminated and sets at 9:45 PM. Observers may need an unobstructed view to catch this elusive planet.

The waning 17-day-old Moon inhabits Capricornus on both nights, blazes at minus 11th magnitude and appears over 90 percent illuminated. The Moon rises at 9:31 PM on Monday, and at 10:08 PM Tuesday; it sets after sunrise on both days.

Neptune rises in Aquarius at 11 PM and is best observed at 4:40 AM. This gas giant planet shines at 7.8 magnitude and is a tiny 2 arc-seconds in size. Uranus, in Pisces, is brighter at magnitude 5.8, a bit bigger at 3.5 arc-seconds and rises at 12:42 AM. Both planets require detailed finder charts from astronomy magazines and apps.

Sky watchers do not need finder charts to see Venus, which blazes in Taurus at minus 4th magnitude and rises at 2:42 AM. In binoculars or telescopes it appears about two-thirds illuminated. Venus acts as a guide to the star Aldebaran, 3 degrees below Venus and the Pleiades star cluster, 9 degrees to Venus’ upper right.

At nightfall, the “W” shaped constellation Cassiopeia points to a home plate shaped Cepheus. Cepheus is home to a famous star, Delta Cephei. Some stars vary in brightness because they are eclipsed by another star, dust cloud, or planet. Delta belongs to group of stars that vary because of changes within the star itself. Variable stars have been known since antiquity. Algol and Mira are examples. What makes Delta Cephei so special is that Henrietta Leavitt discovered that its variations indicate its brightness; the period is linked to the brightness. If an observer sees a Cepheid variable, he knows how bright it truly is. Since he sees it dimmer, the astronomer can estimate approximately how far away it is. The Cepheids made it possible to discover the vast distances between our galaxy and other galaxies. Cepheids are among the tools astronomers use to gauge the size of the universe.

Cassiopeia and Cepheus are related constellations. They were legendary king and queen of Ethiopia. The constellation’s “W” shape is explained in Greek mythology. Cassiopeia thought she was more beautiful than some goddesses. The offended divinities tied her to a chair and placed it near the North Pole, where half the year she sits upright and the other half head down. King Cepheus is part of the Andromeda story, which will be explained when that constellation becomes prominent.

Skywatch Line for Friday, July 7, through Sunday, July 9, 2017

This is Dudley Observatory’s Skywatch Line for Friday, July 7, through Sunday, July 9, written by Sam Salem.

On Friday, Sun rises at 5:25am and sets at 8:36pm; Moon sets at 4:20am and rises at 7:19pm. Full Moon occurs on Sunday at 12:07am. The Moon is astronomically full when it is precisely 180 degrees opposite the Sun in ecliptic longitude. Look for the Moon to appear low in eastern sky around sunset on Saturday. It will climb highest up for the night around midnight and will shine low in western sky at dawn on Sunday. The full Moon lies almost opposite the Sun, therefore, the path of the July full Moon across the nighttime sky will resemble that of the January Sun across the daytime sky. July full Moon is often called the Buck Moon, Thunder Moon, or Hay Moon. This is the time of year when buck deer begin to grow soft antlers and farmers put hay in their barns in the middle of the summer season’s frequent thundershowers.

Each day the Sun loses a little more altitude as it moves southward along the ecliptic, resulting in longer nights and shorter days. Mercury is now beginning a relatively lengthy evening apparition. If you have an unobstructed west horizon, try to locate Mercury with binoculars. Mercury shines at magnitude –0.5 and sets an hour after the Sun. Jupiter, at magnitude –2.0, shines roughly 25 degrees above the southwest horizon. Saturn, at 0.1 magnitude, is still gaining altitude. Saturn reaches the meridian at around 11:30pm. Venus rises with the stars of Taurus at roughly 3am. The “morning star” sits roughly midway between the Pleiades and Aldebaran.

On Friday night, the Moon, Saturn and the bright star Antares come out first thing after sunset in south to southwest sky and stay out until the wee hours after midnight. This year the north side of Saturn rings are maximally tilted toward Earth, offering the best view of the rings in years. The 1st-magnitude star Antares is called the Heart of the Scorpion in the constellation Scorpius. Antares is radiantly bright and reddish in color. Antares is also seen as a twinkle star because of its low altitude as seen from the Northern Hemisphere.

Albireo is one of the season’s prettiest stars. Situated in the constellation Cygnus, Albireo marks the foot of the Northern Cross. Albireo’s pair stars at magnitudes 3.4 and 4.7 are reasonably bright even in full-Moon light. Due to the contrasting colors of its two stars, Albireo looks interesting in any size telescope. The brighter component is a golden yellow, while its companion is a pale, icy blue. Yellow-orange stars tend to be relatively cool compared with bluish-white ones.

Sunday marks the birth date of James B. Pollack. Born on July 9 1938, the American scientist of NASA helped develop the theory that atomic war would result in a “nuclear winter”. James, a world-renowned expert in the study of planetary atmospheres and particulates, examined evolutionary climate change on all the terrestrial planets. He detailed models of the early evolution of the giant gas planets. He made fundamental contributions to the design of numerous NASA missions. Pollack discovered the first real evidence that the clouds of Venus are composed of sulfuric acid. Additionally, he explained why Saturn’s rings showed low microwave emissivity but high radar reflectivity.

Skywatch Line for Wednesday, July 5th, and Thursday, July 6th, 2017

This is the Dudley Observatory Skywatch Line for Wednesday, July 5th, and Thursday, July 6th, written by Louis Suarato.

The 91% illuminated, waxing gibbous Moon rises at 5:32 p.m. Wednesday. When the sky darkens, you’ll notice the Moon is left of the head of the scorpion, the top of the constellation Scorpius. Scorpius is one of the largest, and brightest, constellations in the summer sky. Scorpius is the home to globular cluster M4, M6, the Butterfly Cluster, M7, Ptolemy’s Cluster, and the globular cluster M80. Saturn follows the Moon through the night sky, rising 1 hour and 20 minutes later. Thursday night, the Moon and Saturn will be separated by 3 degrees. Jupiter can be found above the southwestern horizon, shining in the constellation Virgo. Venus rises in Taurus at 2:47 a.m. Thursday, and is the highlight of the dawn sky. Look for the Pleiades star cluster about 7 degrees above Venus.

As the spacecraft Cassini is completing its Grand Finale, diving through the rings of Saturn, consider other NASA spacecraft currently orbiting the Moon and planets. Artemis P1/P2 arrived at the Moon in July 2011, studying the effect of the solar wind. The Lunar Reconnaissance Orbiter which arrived at the Moon on June 23, 2009, is mapping the lunar surface, and locating potential resources. The Mars Reconnaissance Orbiter arrived at the red planet on March 10, 2006, and joined the Mars Global Surveyor, the Mars Express, and the 2001 Mars Odyssey. The Mars Global Surveyor mission ended in January 2007. On July 5, 2016, the spacecraft Juno reached Jupiter to collect data on the planet’s gravity field, magnetic field and polar magnetoshere.

July 5th is the birth date of astronomer Andrew Ellicott Douglass. Born in 1867, Ellicott discovered a correlation between the width of tree rings and sunspot activity. Among Douglass’ achievements is the first photograph of the zodiacal light.

Skywatch Line for Monday and Tuesday, July 3rd and 4th, 2017

This is the Skywatch Line for Monday and Tuesday, July 3rd and 4th.

The Sun sets at 8:37 PM; night falls at 10:51. Dawn breaks at 3:08 AM and ends with the Sun rising at 5:22.

Monday is auspicious for several astronomical reasons. Three weeks ago, the Earth experienced the Summer Solstice, when the Sun is highest in the sky and daylight is longest. On the Fourth of July, the Earth is at aphelion: its furthest from the Sun – 94 million miles or 152 million kilometers. The northern hemisphere undergoes hot summers because Earth is tilted, and that tilt points to the Sun and its warming rays. Ironically, the Northern Hemisphere is warmest when Earth is furthest from the Sun.

The 10-day-old Moon blazes at minus 10th magnitude in the constellation Libra. It appears about 78 percent illuminated, is best observed at 9:07 PM and sets at 2:29 AM, Tuesday. Tuesday evening finds a brighter and fuller Moon also in Libra. It is best observed at 9:51 PM and sets at 3:02 AM on Wednesday.

Jupiter is the next brightest object, shining at minus 2nd magnitude in Virgo. It appears about 11 degrees east of the bright star Spica and near Virgo’s second brightest star Porrima. Monday night, the Jovian Moon Io begins to cross Jupiter’s face at 11:03 PM, followed by its shadow. Jupiter is best observed at 7 PM and sets after Midnight.

When you are done observing Jupiter, turn your attention to the close star Porrima. The Latin name refers to a goddess of Prophesy. Porrima is a double star. Both stars are nearly identical. They are about the same brightness, third magnitude, and the same mass, about 1.5 times the Sun. They are sun-like, but significantly brighter and warmer. Like the Sun, Porrima and its companion are main sequence stars, fusing hydrogen into helium. Porrima was among the first double star systems discovered. Sir John Herschel calculated their orbit in 1833. They share a highly elliptical orbit, which make one cycle in about 169 years. An observer, with 100 power eyepieces in the telescope, can see them about 1.7 arc seconds apart.

Saturn is the next brightest planet, at 0.1 magnitude in the dim constellation Ophiuchus. At 17 degrees above the horizon, this is as far south Saturn can be. Saturn is best observed at 11:30 PM and sets at 4:11 AM.

Eighth magnitude Neptune rises before Midnight in Aquarius and remains up all night. Fifth magnitude Uranus, in Pisces rises at 1:09 AM.

Venus rises at 2:45 AM in Taurus, blazing at minus 4th magnitude and appearing about 64 percent illuminated. This brightest object in the eastern Dawn lies about 7 degrees below the Pleiades star asterism. Early rising binocular observers can find them closest during the pre-dawn on July 5th.

The Fourth of July is famous for fireworks. In the year 1054 Nature staged her own fireworks show. Chinese astronomers saw a new star in Taurus. Eyewitness accounts said it “shone like a comet.” The “guest star” shone in daylight for 23 days and was visible nightly for a year and a half. Many textbooks remark that no one in Europe or the Mideast saw it. However, North American Natives saw it and made rock carvings depicting it. Charles Messier made it the first in his list of false comet objects. We now know it blazed with the brightness of 500 million suns and produced a pulsar, a residue body that spins rapidly and emits regular radio pulses.

Skywatch Line for Friday, June 30, through Sunday, July 2, 2017

This is Dudley Observatory’s Skywatch Line for Friday, June 30, through Sunday, July 2, written by Sam Salem.

On Friday, Sun rises at 5:21am and sets at 8:38pm; first quarter Moon occurs at 8:51pm; Moon sets at 12:33am and rises at 12:41pm. Jupiter is near the first quarter Moon on Friday and Saturday. The Moon guides you to Spica on Saturday. Spica, the1st-magnitude star in the constellation Virgo, the Maiden, resides nearby the Moon and Jupiter. Jupiter, the fifth planet outward from the Sun, will remain in front of the constellation Virgo until mid-November. The position of the Moon changes relative to Spica and Jupiter as darkness falls. The Moon continually moves eastward in front of the backdrop stars of the zodiac at the rate of about one-half degree per hour or about 13 degrees per day. The Moon’s diameter approximates one-half degree of sky, and a fist at an arm’s length spans about 10 degrees on the sky’s dome. Jupiter shines to the west of Spica. Jupiter sets around1:02am and Spica sets around 1:05am on Sunday morning.

Watch Venus travels in front of the constellation Taurus the Bull throughout July. Look eastward, an hour or two before sunrise. Venus will draw your eye to the Bull’s star Aldebaran and the Pleiades star cluster. The ecliptic, the Sun’s yearly path through the constellations of the zodiac, passes through the constellation Taurus the Bull, to the north of the star Aldebaran and to the south of the Pleiades stars cluster. Venus will pair up with Aldebaran by middle July. In August, Venus will depart from the constellation Taurus to enter the constellation Gemini. The ancients found that Venus returns to the same place in front of the background stars in cycles of 8 years.

As we are getting ready for the Great American Eclipse in August 21, Friday mark the anniversary of the longest solar eclipse in 1,000 years. In June 30, 1973, the maximum totality exceeded 7 minutes. The eclipse was observed by British, French and American scientists aboard the French prototype Concorde 001 supersonic aircraft on a flight from Las Palmas, Canaries to Fort Lamy, Chad. The path of totality crossed the Atlantic, the Sahara Desert and East Africa. The Moon’s shadow travelled at over 3,000 km per hour. Flying at 55,000 feet, the jet’s speed made possible a continuous view of the solar eclipse for 74 minutes, ten times longer than could be seen by an observer on the ground. The last total eclipse lasted over 7 minutes was on July 1, 1098. The next total eclipse exceeding seven minutes in duration will not occur until June 25, 2150. For August 21, 2017 Solar Eclipse, the totality lasts a maximum of 2 minutes and 40 seconds.

Friday is the International Asteroid Day. It is an annual global event that aims to raise awareness about asteroids and what can be done to protect the Earth, its families, communities, and future generations. Asteroid Day is held on the anniversary of the June 30, 1908 Siberian Tunguska event, the most harmful known asteroid-related event on Earth in recent history. The United Nations has proclaimed that Asteroid Day will be observed globally on June 30 every year in its resolution. Over 200 astronauts, scientists, technologists and artists co-signed the Asteroid Day Declaration. Asteroid Day was officially launched on December 3, 2014.
The Dudley Observatory celebrates the International Asteroid Day. Come to miSci for a fun filled day all about asteroids! Tour the galleries, see a planetarium show, and participate in space-themed hands on activities. Great for all ages!