Skywatch line for Wed. and Thurs., July 30 and 31, 2008:
by Ray Bogucki

On Tuesday, the Moon was at perigee, its closest approach to the Earth in its monthly elliptical orbit. This insures that for the next few days, the Moon's disk in the sky will appear somewhat larger than normal. On Thursday, the Moon, one day from its New Moon phase, will occult the asteroid Ceres. This occultation is a minor event since Ceres is not quite bright enough to see with the naked eye, it occurs so close to the Sun that it would be difficult to detect in the bright twilight and, in any case, it is only visible in Madagascar and Southwestern Australia. We mention this occultation mainly to introduce an interesting historical aside concerning Ceres. Ceres is the first asteroid to be discovered. In the first hour of the first day in the 19th century, Sicilian astronomer, Guiseppe Piazzi discovered a faint, star-like object moving slowly through the stars. Astronomers were searching for a "missing planet" expected to be in orbit between Mars and Jupiter. Piazzi believed he had found it and named it Ceres. In the next few years, several more, similar objects were discovered and astronomers realized that there was a large belt of small objects in orbit between Mars and Jupiter, now known as the asteroid belt. Ceres is the largest of the asteroids. It has a diameter of about 550 miles and its mass constitutes roughly one quarter of the total mass of the tens of thousands of asteroids in the belt.

We are now in the second of the two eclipse seasons that occur each year, and on Friday, August 1, the precisely New Moon, having occulted Ceres, will occult our parent star, the Sun. The Moon's disk will be large enough to completely cover the Sun so we will experience a total solar eclipse. The path of totality will begin at sunrise in northwestern Canada, move rapidly eastward across the northern tip of Greenland, swing across the Arctic Ocean close to the North Pole, then enter Russian Siberia, passing through Novosibirsk. It will continue through Mongolia and China where the eclipse will end at sunset near the famous Silk Road.

Many tour groups will view the eclipse from the deck of a Russian icebreaker near the North Pole, from land sites in Siberia and China, and even from a polar flight on a special airliner. In two weeks, still in the eclipse season, Asia, Europe and Africa will witness a partial lunar eclipse but, at this location, we will witness moonrise just after the eclipse has ended.

 

This is the Skywatch Line for Monday and Tuesday, July Twenty-Eighth and Twenty-Ninth.
by Joe Slomka

The Sun sets at 8:19 PM, with night falling at 10:19. Dawn breaks at 3:43 AM and ends with sunrise at 5:43.

Planets shine at opposite ends of sunset sky. Low in the West, Mars and Saturn prepare to set. Venus is even lower, and requires binoculars to find amid the twilight. All three planets set by 10 PM. Meanwhile, Jupiter is already risen and low in the East. Binocular observers can track the four Galilean Moons, while telescopic observers behold the planet's ever changing cloud patterns.

Twilight's end finds Jupiter due South and ideal for observation. Neptune appears as a tiny blue dot above the tail of Capricornus. Uranus is also a tiny dot amid the empty spaces of Aquarius. Astronomy magazines and websites provide exact positions for these distant worlds. If the observer encounters meteors while hunting for Uranus and Neptune, he is witnessing the annual Delta Aquarid meteor shower. The shower actually peaked last night, but late night observers should see some dim meteors between nightfall and 2 AM, when the 26 day-old Moon brightens the sky.

About an hour before Wednesday's sunrise, you will see a thin crescent Moon and the stars Castor and Pollux form a trio low in the East-Northeast, if the horizon is clear.

Only two constellations refer to real people. Coma Berenices lies above Leo’s tail, and is now lost in the sunset. The other constellation, Scutum, is now visible in summer skies. Scutum is a dim constellation above teapot-shaped Sagittarius within the glorious Milky Way. It is the fifth smallest. The astronomer Johannes Hevelius named it for the Polish King Jan Sobieski. The Ottoman Empire threatened to invade Europe. Sobieski commanded an allied army and stopped the Turks outside of Vienna. Hevelius created Scutum partially to commemorate this victory, but also to thank the king for rebuilding his Gdansk observatory.

Clear Skies
Joe Slomka

Skywatch line for Wed. and Thurs., July 23 and 24, 2008:
by Ray Bogucki

Charles Messier was a French comet hunter who lived in the 18th century. Comets usually appeared as faint, fuzzy patches of light which move through the stars as they orbit around the Sun. In his nightly searches, Messier was often fooled temporarily by fuzzy patches of light that did not move and were thus seen as permanent objects in the sky. To spare other comet hunters from mistaking these permanent objects for comets, he published, in 1787, a list of 110 objects which have become known as Messier objects, and which are designated by a capital M. For example, the star cluster called the "Pleiades" is also known as M45.

Returning from last week's Skywatch line to the bright constellation Sagittarius, low in the south at nightfall, we find this area of the Milky Way is packed with more Messier objects than any other part of the sky. There are many open star clusters and globular clusters, including the bright M22, a couple of degrees to the left of the star that marks the top of the Teapot's lid. Several diffuse nebulae stretch up northward from the Teapot, including the Lagoon (M8), the Trifid (M20), the Omega (M17), and the Eagle (M16). About four finger widths above the Teapot is the large star cluster, M24, known as the Small Sagittarius Star Cloud. In this region, stars are much more closely packed than they are in our quiet exurbs of the galaxy. Inhabitants of a planet in this area would see skies with hundreds of brilliant, sparkling stars that would far outshine our modest constellations.

The most fascinating and mysterious of all objects in Sagittarius lies a few degrees to the right of the spout on the Teapot. In this direction we are looking directly at the center, or hub, of our galaxy, but unfortunately, we cannot see it because of huge clouds of dust and gas that block our view in the visible wave lengths of light. However, infrared and radio wave lengths can penetrate the clouds and the images they show are truly mind-boggling. The huge central galactic bulge contains hundreds of millions of stars revolving around the crowded center at blinding speeds with frequent near misses and occasional cataclysmic collisions. Most astronomers believe that at the dead center of the bulge sits a massive black hole with a mass more than a million times the mass of our Sun. Matter falling into the black hole is heated to millions of degrees, whereupon it bathes the entire central galactic area with a lethal radiation of X-rays.

We are most fortunate to live on a small planet far from the toxic galactic center, revolving around a lonely, modest, well-behaved star with a few interesting and non-threatening planetary siblings.

 

This is the Skywatch Line for Monday and Tuesday, July Twenty-First and Twenty-Second.
by Joe Slomka

The Sun sets at 8:25 PM, with night falling at 10:30. Dawn breaks at 3:32 AM and ends with sunrise at 5:36.

Sunset becomes busy. Mars and Saturn are low in the southwest, preparing to set by 10:15 PM. Now is the time for last looks. A bright star-like object lies lower in the West; this is the planet Venus. All July, Venus struggles to be seen through the twilight. It takes luck and a clear horizon to spot Venus. If you are unsuccessful, Venus gets better later in the month. Venus sets by 9:08 PM.

Jupiter has already risen and is up virtually all night. By nightfall, Jupiter is ideally situated for observation. It blazes East of the teapot handle of Sagittarius. Binoculars or low power telescope easily shows the four Galilean moons. Monday's nightfall has Io to one side, with Europa, Ganymede and Callisto on the other; Tuesday's nightfall has all four on the same side. Telescopes with high power shows Io beginning to cross Jupiter's face at fifty-five minutes after midnight. Io's shadow follows twenty minutes later. Io and its shadow parade across Jupiter for the rest of the night.

The eighteen-day-old Moon rises after 10 PM and obscures most of the southern sky with its brilliance.

By 1:15 AM on Wednesday morning, the constellation Perseus and its star Algol are up in the northeast. Algol, the “Demon Star,” varies its light every 2 days, 20 hours and 49 minutes. It fades from second magnitude to third – easily seen by the naked eye. Two hundred twenty-five years ago, John Goodricke theorized that a dimmer star was partially eclipsing a brighter star. In 1889, the new technique of spectroscopy verified his theory. The main star is one hundred times the Sun’s luminosity. The eclipsing star is actually slightly brighter than our Sun. There is a third star that orbits the system once every 1.8 years, but plays little part in the occultation. The system is about 100 light years away and the most easily studied “eclipsing binary.” Algol has its minimum at 1:16 AM on Wednesday.

Clear Skies
Joe Slomka

 

This is Dudley Observatory's Skywatch Line for Friday, July 18, through Sunday, July 20, written by Alan French.

The Moon was Full at 4:59 AM Friday morning, so a bright waning gibbous Moon will dominate this weekend's night sky.

This weekend the International Space Station will make many passes over our area, both in the early morning hours before sunrise and in the evening hours after sunset. We'll give the times for some of the better passes, but can't possibly cover them all. For a complete list of appearances, visit www.heavens-above.com <http://www.heavens-above.com/>, enter your location, and then click on the “ISS” to get all passes over your site. It is now very easy to select a location, with three methods provided. You can directly enter your latitude and longitude if you know it, find your location on a map, or select it from their database. Once you have your site selected, save the page in your favorites for future use.

We see the ISS because it is still up in sunlight while we are down in the Earth's shadow. The ISS is quite large and reflects a lot of sunlight, so it appears brighter than any of the stars as it glides across the night sky. Times will be given in hours, minutes, and seconds. They are for Schenectady, but should be close enough for anyone in the Capital District.

The highest and brightest pass of the ISS this weekend occurs early Saturday morning. The ISS will first appear rising up from the west-northwestern horizon at 4:11:39 AM. It will be highest at 4:14:31 when it will be 68 degrees above the southwestern horizon. It will vanish below the southeastern horizon at 4:17:24. Its path will bring it up through Hercules, Lyra, and Cygnus, and then down through Pegasus, Pisces, and Cetus.

The best evening appearance of the ISS will be on Saturday night. The ISS will rise from the west-southwestern horizon at 10:12:55 PM. It will be highest at 61 degrees above the north-northwestern horizon at 10:15:45, and will vanish in the northeast at 10:18:35. The ISS will glide past the end star in the Big Dipper's handle, and then just above the bowl of the Little Dipper.

I always enjoy seeing the ISS when the sky is still bright and only the brighter stars are visible. On Sunday night you'll have a chance to see the space station early in the evening before night has completely fallen. Look for it moving up from the south-southwestern horizon at 9:01:34 PM. It will be highest at 9:04:17 when it will be 41 degrees above the southeastern horizon, and move below the horizon in the east-northeast at 9:06:59.

 

Skywatch line for Wed. & Thurs., July 16 & 17, 2008:
by Ray Bogucki

As the sky darkens this week, the spectacular constellation, Scorpius the Scorpion, is crossing the southern meridian, riding as high in the southern sky as it ever does from this location. Following close behind Scorpius is the next Zodiac constellation, Sagittarius, the Archer. By midnight, Sagittarius has replaced Scorpius on the southern meridian, and is best placed for observation. While it might take a creative imagination to picture an archer in the stars of Sagittarius, it is easy to pick out the arrangement of stars, or asterism, known as "The Teapot". It is particularly easy to find this summer, because the unmistakable, brilliant planet Jupiter lies just to the left of the Teapot, whose handle lies on the left with its spout pointing to the right. A bright star, Kaus Borealis, marks the top of the lid. The word "Kaus" means bow, so this star marks the northern tip of the archer's bent bow, while the star at the base of the spout marks the southern tip of the bow. The star at the pouring tip of the spout is El Nasl, which translates as "The Point" at the tip of the arrow.

The Teapot is imbedded in a rich part of the Milky Way, and is surrounded by a rich field of some of the most fascinating celestial sights anywhere in Earth's sky. In a dark sky, a puff of steam seems to be issuing from the spout of the Teapot. This large association of distant stars is known as the Large Sagittarius Starcloud. This starcloud and most of the other objects in this area, except the Teapot stars themselves, lie in the Sagittarius Arm of our Milky Way galaxy which is the next spiral arm lying inward toward the center of the galaxy, 30,000 light years away from our location in the Orion arm of the galaxy.

At the top of the Large Sagittarius Starcloud is a fuzzy object, easily seen in binoculars, known as M8, the Lagoon Nebula. A telescope shows it to be a beautiful cluster of stars imbedded in a large cloud of hydrogen gas and dust, 5,700 light years away. It is a large star nursery where new stars are being born. It is the summertime equivalent to winter's Great Orion Nebula.

About one degree above the Lagoon Nebula lies the Trifid Nebula which appears to be split into three parts, like a flower with three petals. In long, time exposure photographs, this nebula glows the classic orange-pink color of fluorescing hydrogen atoms, excited by the ultraviolet radiation from a giant white star imbedded deep in the nebula. More, interesting aspects of Sagittarius next week.

 

This is the Skywatch Line for Monday and Tuesday, July 14th and 15th.
by Joe Slomka

The Sun sets at 8:30 PM, with night falling at 10:40. Dawn breaks at 3:21 AM and ends with sunrise at 5:30.

The Moon is already in the sky before sunset. Monday night finds the twelve-day-old Moon next to the bright star Antares, in Scorpius. Tuesday night sees an almost Full Moon between Scorpius and teapot-shaped Sagittarius. The Moon sets before midnight on both nights.

As the sky darkens, the alignment of Mars, Saturn and Regulus changes. Mars passes Saturn, and lies two degrees below the Ringed Planet. Mars continues to charge eastward toward Virgo. Mars is in a losing race with the Sun; Mars, Saturn and Regulus set earlier each night. The brilliant planet Venus blazes low in the West; however, it is so low that trees and hills may obstruct the view. Venus slowly improves over the next few months.

Jupiter rises before sunset and lies due South by midnight. The Solar System's largest planet is ideally placed for observation for most of the night. Binoculars reveal its four Galilean moons, while telescopes reveal its complex weather systems.

Mercury rises before sunrise. Mercury is the subject of renewed interest due to findings by the recent Messenger space probe. Messenger passes Mercury a few times before settling into orbit around this closest planet to the Sun. Mercury appears bright and star-like low in the East. Binoculars may help finding it amid the brightening sky; telescopes reveal a three-quarters illuminated crescent.

Most of the constellations and planets came to us through the Mesopotamians, who were expert astronomers. Jupiter is an example. Mesopotamian legends tell of a fierce war between clans of gods. Marduk led one clan, conquered his opponents, founded the Earth, as we know it, and established Babylon as the center of the world. The planet we call "Jupiter" was his “star.” Many scientists believe that Earth could not exist without Jupiter. Jupiter acts as a gigantic “magnet,” attracting comets and asteroids that would otherwise threaten the development of life on Earth; an example is 1994’s Comet Shoemaker-Levy 9, which crashed onto Jupiter.

Clear Skies
Joe Slomka

This is Dudley Observatory's Skywatch Line for Friday, July 11, through Sunday, July 13, written by Alan French.

Mars and Saturn continue their close dance in the western sky just after sunset. Look for the pair just over ten degrees above the western horizon at 9:45 PM. Reddish Mars will be to the left and yellowish Saturn will be to the right. Below and to the right of the pair will be Regulus, the brightest star in Leo, the Lion.

On Friday night Mars will be one degree from Saturn. By Saturday the distance will have increased to 1.4 degrees, and it will be approaching 2 degrees by Sunday.

The Schenectady Museum and Suits-Bueche Planetarium are hosting “Stars of the Season” from 7 until 10 PM on Friday night. The museum will be open, there will be planetarium shows, and, weather permitting, there will be lunar observing. There is an admission charge to the museum. Call the museum at 382-7890 for more information.

The Albany Area Amateur Astronomers will be participating in Canalfest 2008 in Glenville's Maalwyck Park this weekend. From 11 AM until 4 PM on Saturday and Sunday, weather permitting, special solar telescopes will provide safe views of the Sun. Specialized H-alpha filtered telescopes will allow viewing solar prominences – huge eruptions of hydrogen gas from the Sun. A high resolution solar spectroscope will reveal hundreds of dark absorption lines in the solar spectrum.

There will also be a walking tour of a scale model of the solar system on Saturday. On both days, members of the Albany Area Amateur Astronomers will be on hand to answer questions about astronomy and telescopes.

Maalwyck Park is located just west of Scotia on the south side of Route 5. Look for Maalwyck Park Road near where the speed limit changes from or to the village's 30 MPH limit.

If the skies are clear, the club will hold a star party, featuring views of the Moon, in Glenville's Indian Meadows park beginning at 10 PM on Saturday night. Indian Meadows Park is off of Droms Road not far from the YMCA. The entrance is marked by a large wooden sign. The star party is open to all, and there is no admission charge. Call 374-8460 for more information.

Skywatch line for Wed. & Thurs., July 9 & 10, 2008
by Ray Bogucki

The Red Planet, Mars, with its faster orbital speed, has been approaching the Ringed Planet, Saturn, all through the Spring. Tonight (Wednesday) and tomorrow night, Mars finally catches up and these two worlds will be at their closest approach for this orbital cycle, about 0.7 degrees or a little more than one Moon-width apart. The pair of planets will be visible in the same field of view in binoculars and even in a telescope at low magnification. Look for them low in the west as the sky darkens, about 6 degrees to the upper left of the bright star, Regulus, in the constellation, Leo, the Lion. Mars lies directly below Saturn tonight and appears much fainter than Saturn. Mars is still receding from Earth and now lies about 200 million miles away from us. Even though Saturn is four times farther away, it appears more than twice as bright as Mars for a combination of reasons. First, Saturn is much larger than Mars, with a diameter almost 18 times that of Mars. It also has a large ring system which also reflects considerable sunlight and adds to the brightness of the planetary globe of Saturn. Finally, Saturn's gaseous surface is more than 3 times more reflective than the dull, rocky surface of Mars. This close pairing is worth a careful look because these two worlds will not appear this close together again in Earth's sky until the year 2022. Saturn's ring system is tilted 8 degrees from edge-on this weekend and the telescopic view of this giant planet with its perfectly flat ring system and its many moons remains one of the most awesome sights anywhere in our night sky.

 

This is the Skywatch Line for Monday and Tuesday, July Seventh and Eighth.
by Joe Slomka

The Sun sets at 8:34 PM; night falls at 10:48. Dawn breaks at 3:11 AM, ending with sunrise at 5:25.

As the sky darkens, a five-day-old Moon hangs in the southwest. If the western horizon is clear, Venus may be spotted - binoculars may assist. If unsuccessful, keep trying. Brilliant Venus becomes easier as the month continues.

Later, Saturn, Regulus and Mars appear, low in the southwest. All three prepare to exit. Mars speeds eastward. Monday night finds it one and a half degrees from the star Regulus; Tuesday night has it only a degree apart. Saturn lies about a degree and a half from Regulus. By week's end, Mars and Saturn are in conjunction - seven tenths of a degree apart. A great binocular or telescopic sight!

Nightfall finds Jupiter already risen as Saturn and Mars set. Jupiter is at opposition this week. This means that Jupiter rises at sunset, and sets at sunrise; it also means that Jupiter is observable all night. Now is a perfect time to note the position of the four Galilean moons and how they shift position over time. Telescopes display bands of Jovian weather systems. High power views may present the Great Red Spot - a three hundred year old hurricane. Astronomy magazines and websites provide charts and timetables for the moons and Great Red Spot.

Midnight finds Jupiter highest and due South. Neptune, a giant planet, can be found above the tail-star of Capricornus. It lies two degrees above the star, and can be seen in amateur telescopes under high power. Again, websites and magazines provide finder charts.

Shortly before Dawn, Mercury is located low in the East. It rises at 4 AM and appears as a bright star amid the rapidly brightening sky. Telescopes exhibit it as half illuminated.

At sunset, Vega blazes in the constellation Lyra. It is a famous star; it is very bright and it forms one point in the Summer Triangle. Recently, astronomers learned that Vega spins very rapidly and points its poles at us. In fact, if Vega has any inhabited planets, its citizens would see our Sun as their polestar.

Clear Skies
Joe Slomka

Skywatch line for Wed. and Thur., July 2 & 3, 2008
by Ray Bogucki

The Zodiac constellation, Scorpius the Scorpion, shines low on the southern horizon at nightfall on these early summer evenings. Although it is one of the brightest constellations, it is not so well known to northern observers because it lies so far south of the celestial equator, and is only visible in evening prime time viewing in June and July.

The location of Scorpius in this part of the sky has an interesting historical basis. In Greek and Roman mythology, the Hunter, Orion, was very efficient at killing animals. In fact, Orion boasted that he would kill all animals on Earth. Alarmed, the gods sent the scorpion to sting Orion and put an end to the slaughter. Orion died from the scorpion's sting, and to recognize his prowess as a hunter, the gods placed Orion in the winter sky. To reward Scorpius for his service, the gods also placed him among the stars, but on the other side of the sky so that the two enemies could never fight again. So in late Spring, as Scorpius rises in the southeast, Orion is setting in the west.

Another highlight in the history of Scorpius occurred at the time that Julius Caesar established the Julian calendar. The Roman astronomers decided that the Zodiac, the list of constellations that the Sun passed through sequentially in its annual path through the stars, needed another member. To create this new member, the astronomers cut the claws off the Scorpion to form the new constellation, Libra, the Scales, the only inanimate object in the Zodiac. The two brightest stars in Libra, however, still carry the mellifluous Arabic names, Zuben Eschamil (meaning the Northern Claw) and Zuben el Genubi (the Southern Claw).

There are many attractive telescopic sights in the constellation Scorpius. Just one degree, or two Moon-widths west of the giant red star Antares, lies the globular star cluster known as M4, one of the nearest globular clusters to the Sun. At the other end of the Scorpion, a few degrees to the northeast of the two bright stars that form the Scorpion's "stinger", lie two impressive open, or galactic, star clusters that are favorite targets for backyard astronomers. In fact, one could spend an entire evening, slowly sweeping this rich area of the Milky Way with binoculars and encountering an array of fascinating sights.

 

This is the Skywatch Line for Monday and Tuesday, June 30th and July First.
by Joe Slomka

The Sun sets at 8:36 PM; night falls at 10:53. Dawn breaks at 3:04 AM and ends with sunrise at 5:20.

As the sky darkens, Saturn, Regulus and Mars remain in southwestern skies. Mars lies a half-degree above the star Regulus, while Saturn lingers four and a half degrees from Mars. The whole scene can be captured within most binocular views. Venus blazes low in the West; its minus fourth magnitude punctures the sky glow. If you are blessed with clear eastern and western horizons, it is possible to observe Venus setting while Jupiter rises.

Just before sunrise, Jupiter prepares to set, while Mercury rises. Tuesday morning, Mercury lies seven and a half degrees below a very thin Moon. Wednesday morning finds Mercury above an exceedingly thin Moon. The Moon turns "New" eighteen hours later.

About 7:15 AM, on June 30, 1908, a bright object roared out of the sky and exploded over a Siberian forest. The resulting blast knocked people off their feet 70 kilometers away. Night skies were so bright the one could read a newspaper at midnight. Barometers around the world monitored the blast wave. Monday is the one hundredth anniversary of the Tunguska Event.

The region, near the Tunguska River, was so remote that it took years for word to arrive at Moscow. Twenty years later, scientist Leonid Kulik led an expedition. He found the forest devastated for miles, with trees felled in a radial pattern from a central area. Suspecting a meteor, the expedition dredged the swamp to no avail.

Thanks to microscopic traces, we now know that the object was an asteroid that entered the Earth's atmosphere. It exploded several miles above the surface with a force between three and five times the Hiroshima Atomic Bomb. Recent research also revealed that the object was smaller than first thought. In 1947, a large asteroid broke apart and impacted the Kamchatka Peninsula, also in Russia. Pictures exist showing Soviet trucks pulling thousand kilo meteorites from the ground. Today, meteor collectors buy pieces of the Sikote-Alin meteorite, as it is now called.

Clear Skies
Joe Slomka