Archive for January, 2014

The Sky This Week : January 21 – 28, 2014 !

The Sky This Week, 2014 January 21 – 28
Star clusters galore…
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Messier 37, galactic star cluster in Auriga

Imaged 2014 January 2 from Morattico, VA
with an 80mm (3.1-inch) f/6 Antares Sentinel refractor
and a Canon EOS Rebel T2i DSLR

The Moon wanes in the morning sky this week, passing through the rising constellations of spring as she dives toward the southern reaches of the ecliptic. Last Quarter occurs on the 24th at 12:19 am Eastern Standard Time. Luna can be found near the brightening planet Mars on the mornings of the 22nd and 23rd. On the latter date she passes just five degrees south of the red planet, while at the same time she’s just half a degree from the bright star Spica. On the morning of the 25th look for the Moon just over west of golden Saturn.

Last week we introduced the mighty Orion Nebula, considered by many amateur astronomers to be the showpiece of the winter sky. This week, with the waning Moon leaving the winter stars behind, it’s a great time to check out some of the other hidden gems of the winter constellations. If you live in a dark location look for the faint glow of the Milky Way. at 9:00 pm it stretches across the sky from the northwest to the southeast, passing through the zenith. The winter version of the Milky Way isn’t as impressive as the vast star clouds we see in the summer since at this time of the year we’re looking in a direction that’s opposite the galactic center. However, owners of small telescopes will be amply rewarded for their “sweeps” of the fuzzy band. Where the summer sky abounds in gaseous nebulae and globular star clusters the winter band offers dozens of galactic clusters for your enjoyment. Some of the best of these are located overhead in the constellation of Auriga, the Charioteer, whose brightest star Capella stands out in golden splendor directly overhead. Auriga’s brightest stars resemble a pentagon, and if you look in the area of the figure that’s opposite Capella you’ll see three knots of light in binoculars. These are the galactic clusters Messier 36, 37, and 38. They are wonderful examples of this type of object which are well-suited for the small telescope. Each one has a unique character in the number and concentration of their stars. My favorite is M37, which contains several hundred stars sprinkled on a background of thousands of more distant Milky Way stars. If you sweep your gaze about halfway between Auriga’s second-brightest star, El-Nath, and Jupiter you’ll run into Messier 35 in the constellation of Gemini. This is a large, scattered group of stars that spreads over an area the size of the Full Moon. It’s easily seen in binoculars, and increasing telescope apertures will reveal progressively fainter stars. In scopes of six inches or more aperture you should be able to spot the even more remote and populous cluster NGC 2158 just to the southwest. If you enjoy these targets, continue to sweep down the Milky Way just east of Orion and into Canis Major. There will be lots of other clusters for you to find.

Jupiter is now well placed for viewing as soon as it gets dark. The giant planet dominates the evening sky, culminating high in the south at around 10:45 pm. The best time to observe him is after 9:00 pm when he should be high enough to clear the heat radiated from nearby rooftops. Try to pick a night to observe him when the stars don’t seem to twinkle; this indicates steady air overhead and should give you good high-power views of the planet and his moons.

Ruddy Mars now rises before midnight, but you’ll need to give him a couple of hours to climb above the trees. The best time to observe him is still in the hours before dawn. His disc is gradually becoming more distinct as Earth catches up to him, and more detail is visible in modest telescopes. His north polar ice cap is particularly prominent at this time.

Saturn is also up before dawn, halfway between Mars and the southeast horizon. At this time he’s also fair game for the telescope, with his rings tipped generously in our direction. You shouldn’t have any trouble identifying him in even the smallest of telescopes.

Finally, keep your eyes on the southeast sky as morning twilight gathers. By about 6:30, if you have a clear horizon in that direction, you should be able to catch a glimpse of Venus as she returns to the morning sky.

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The Sky This Week , January 14 – 21, 2014 !

The Sky This Week, 2014 January 14 – 21
Poking around Orion’s Sword
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Messier 42, the Great Nebula in Orion

Imaged 2014 January 1 from Morattico, Virginia
80mm (3.1-inch) f/6 Antares Sentinel refractor,
iOptron “Cube Pro” portable go-to mount,
Canon EOS Rebel T2i DSLR

30 x 30-second subframes @ ISO 6400

The Full Moon beams down from high among the stars of the Great Winter Circle as the week opens, then wanes to a gibbous phase as she dives toward the southerly reaches of the Ecliptic. Full Moon falls on the 15th at 11:52 pm Eastern Standard Time. It happens to occur within three hours of one of the year’s most extreme lunar apogees, the time when Luna is most distant from the Earth. Much ado has been made in the past several years about “Supermoons”, Full Moons that occur at a time of extreme lunar perigee; this is the opposite case. Perhaps we should call it the “anti-Supermoon”? Luna passes just five degrees to the south of bright Jupiter on the evening of the 14th. On the 18th she is a similar distance to the south of the bright star Regulus. She ends the week by homing in on the planet Mars and the bright star Spica in the pre-dawn sky.

As with much of last week, light from the waning Moon will wash out all but the brightest stars for most of this one as well. If you didn’t get a chance to wend your way around the multi-colored stars of the Great Winter Circle yet you still have that chance to spot them in a bright but relatively uncluttered sky. However, by the end of the week we’ll begin to get a couple of hours of astronomical darkness to look for some of the more subtle showpieces of the winter sky. One of these is located in a tight little asterism that lies just below the famous “Belt Stars” of Orion. Even on a moonlit night under urban skies you should be able to spot the three vertically aligned stars that make up the group known as “The Sword”, and as the sky darkens you might notice that the middle one appears “fuzzy”. A glance at this fuzzy star with binoculars will reveal its true nature as a small group of blue-tinted stars surrounded by a softly-glowing cloud of gas. This is the famous Great Nebula in Orion, which is probably the easiest “deep-sky object” to observe in the entire sky. Larger telescopes and darker skies reveal ever-increasing amounts of detail in the swirling clouds of bright and dark material that make up this object. Most of us suburban stargazers can see the bright central part of the nebula that surrounds a small tight group of four blue stars known as the Trapezium. This gas glows with the characteristic light of doubly-ionized oxygen, stimulated by the intense ultraviolet light from the Trapezium stars themselves. These stars are among the youngest and most energetic stars known in the Galaxy, and the nebula is the brightest part of a huge complex structure that is forming many more such energetic suns. Under progressively darker skies darker clouds of cooler gas and dust reflect the blue light of the central stars, framing the brighter core. In telescopes of six or more inches in aperture the nebula takes on a near “3-D” aspect, filling the eyepiece field with swirling knots and eddies of texture. In my 14-inch telescope from the skies of rural Virginia the central region begins to show a faint greenish tint framing the intense blue blaze of the Trapezium and its neighbor stars. My favorite view, though, is the low-power one I have through my modest 3-inch refractor. This places the nebula in the context of the other stars in the “sword”, each of which resolve into clumps of icy blue-hued luminaries. Although its visual appearance hasn’t changed much since it was first seen in a telescope 400 years ago, the Great Nebula is one of the few objects of its type that appears “dynamic”; I can only imagine the colossal forces of nature that are at work in its glowing heart.

Closer to home we find the bright Moon hanging near Jupiter as the week opens, but you won’t need the Moon around to identify Old Jove on any given night. Jupiter shines down from high among the stars of Gemini and, with the current absence of Venus from the sky, is the brightest object in the heavens after the Sun and Moon. Jupiter is a treat to look at with almost any form of optical aid; even a pair of binoculars will give you a good view of the planet and the four bright moons discovered by Galileo in January of 1610. A particularly good night to do this will be that of the 16th, when all four moons will be well-separated from the planet’s disc. As a bonus on that night, if you have a four-inch or larger scope, the famous Great Red Spot will rotate across the center of the planet at around 8:30 pm.

If you’re up past midnight you can begin to look for Mars rising in the southeastern sky, but the best time to see the red planet is still in the hours before dawn. He’s steadily growing brighter and more prominent in the sky, now only exceeded in brightness by the nearby star Arcturus. His disc is still fairly small for the modest telescope, but steady air in the pre-dawn sky may allow you to see some details, especially his bright north polar ice cap. Mars is located about six degrees northwest of the bright star Spica by the end of the week. He’ll be spending most of next few months near the star.

Saturn is also available for your perusal before sunrise, located in the obscure constellation of Libra, the Scales. Saturn’s rings are now tipped generously in our direction, which makes up somewhat for his southerly declination. Detail is harder to eke out when we have to look through more of Earth’s atmosphere, but the planet’s unusual appearance should nonetheless be easy to make out with a minimum of optical aid.

The Sky This Week , January 7 – 14, 2014 !

The Sky This Week, 2014 January 7 – 14
Circling around the Moon
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Jupiter, with Io and its shadow in transit
Imaged 2014 January 5, 03:42 UT

The Moon waxes to her full phase this week, shining down from a high perch among the stars of the Great Winter Circle. First Quarter occurs on the 7th at 10:39 pm Eastern Standard Time, with Full Moon falling on the 15th at 11:52 pm. January’s Full Moon is popularly known as the Moon After Yule, the Old Moon, or the Wolf Moon. I particularly like the latter name as it conjures images of wolf packs patrolling the frozen ground by its pale light reflected off the snow. Look for Luna near the Pleiades star cluster on the evenings of the 10th and 11th. On the 11 she is also just four degrees northwest of the bright star Aldebaran in the constellation of Taurus, the Bull. On the 14th she’s five degrees south of bright Jupiter.

The brightening Moon will once again begin to wash out the fainter stars as she waxes toward the full phase, but this month in particular she gets some pretty stiff competition from several of the night’s brightest stars. It’s very hard for her to overcome the stars that outline the figure of Orion, the Hunter, and the other bright stars that surround him. If you draw an imaginary line through Orion’s belt stars and extend it to the southeast, you’ll run into the night’s brightest star, Sirius. Although the literal translation of the name means “The Scorcher”, this star is popularly known as The Dog Star due to its location in the constellation of Canis Major, the Greater Dog. If you imagine Sirius as a jewel in a dog’s collar, you can more or less trace out the figure of a faithful canid leaping up at the heels of his master, Orion. From Sirius, sweep your gaze to the northeast to find a more solitary star, Procyon, brightest star in Canis Minor, the Little Dog. Continue upward from here to spot the Gemini Twins, Castor and Pollux. Gemini is currently hosting the planet Jupiter, who overshadows all of his stellar neighbors. Now turn your view to the northwest of the Twin Stars and look for the bright golden glow of Capella, the lead star in the constellation of Auriga, the Charioteer. This star is actually a “quadruple” system, with two red dwarf stars orbiting a more massive pair of yellow giants. The yellow stars were the first pair to be resolved using a technique called “interferometry”. Heading southwest from Capella, we encounter Aldebaran, a rose-tinted star that marks the right “eye” of Taurus, the Bull. Aldebaran appears to be a member of a large V-shaped group of stars called the Hyades, but in reality it lies at about half the distance to this cluster. Finally, sweeping southeast from Aldebaran, we land on Rigel, the brightest (usually) star in Orion. Collectively these stars are known as the Great Winter Circle, and within their bounds you’ll find nine of the 25 brightest stars in the sky.

Remember Venus? Just a week ago I was looking at her from a nice location on Virginia’s Northern Neck, shining like a beacon in the southwestern sky. This week she passes between the Earth and the Sun on the 11th and enters the morning sky. If you want to catch a glimpse of her you’ll now need to rise before the Sun.

Jupiter, just past opposition, rises at sunset and stays in the sky all night. He is now in the prime of the current apparition, and beckons us to investigate. It was 404 years ago on the 7th that Galileo first wrote of his discovery of three of the planet’s large moons (he found the fourth a few weeks later). Today almost any optical instrument will show these worlds, and many of today’s amateur telescopes will reveal much more. Brave the cold weather to sight on the solar system’s largest planet; he is always putting on a show!

Mars and Saturn are best seen in the morning skies, with Mars crossing the meridian at around 6:00 am and Saturn about halfway between Mars and the southeast horizon. Both planets will be well-positioned for viewing once Jupiter has run his course in the late spring.

The Sky This Week , December 31, 2013 thru January 7, 2014 !

The Sky This Week, 2013 December 31 – 2014 January 7
Happy New Year!
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Jupiter, with Io entering eclipse and Ganymede chasing its shadow, 2013 DEC 28, 04:04 – 04:10 UT

The Moon begins the new year as a waxing crescent, with New Moon falling on New Year’s Day at 6:14 am Eastern Standard Time. Luna’s slender crescent can be seen in the southwest about seven degrees northeast of Venus in the bright glow of evening twilight. For the rest of the week her increasing phases pass through the dim constellations of the autumn sky. First Quarter occurs on the 7th at 10:39 pm EST.

Earth reaches perihelion, its closest point to the Sun, on the 4th at 6:59 am. At this moment Earth will be 147,104,792 kilometers (91,406,680 miles) from the center of the Sun. Very little, if any, effect occurs in the amount of sunlight reaching the planet’s surface, as the annual variation in our distance varies by barely three percent. That said, it’s high summer for our friends in the Southern Hemisphere, so if a beach is in your New Year’s plans the south should be your destination.

For those of you who plan to stay up until midnight to welcome in 2014, go outside at the midnight hour and look to the south for the brightest star in the night sky. Easily located just to the southeast of Orion’s three “Belt Stars”, Sirius crosses the meridian as the new year rings in. Right now this is a happy coincidence brought about by the slow precession of the Earth’s rotation axis, but to the ancient Egyptians it was the harbinger of the annual flood of the Nile River when it was seen to rise just before the Sun in mid-summer. This event, known as the heliacal rising of Sothis, was the anchor of the Egyptian calendar and was one of the most celebrated events in their religious calendar. Their civil calendar consisted of 12 months of 30 days with five “intercalary” days added before the secular new year. Over the ages the two calendars would get out of phase with each other, with secular new year corresponding to the heliacal rise about every 1500 years. It is a testament to the duration of their civilization to note that they observed this coincidence three times.

This week we bid a fond farewell to dazzling Venus, which has been a fixture in the southwestern sky for the past several months. The dazzling planet is rapidly overtaking the Earth on her quicker orbit around the Sun and will pass between us and Old Sol on January 11th. This week she seems to plummet from the sky, setting six minutes earlier on successive evenings. She is still very bright and should be relatively easy to spot from a location with a good southwest horizon, and she entertains a very young crescent Moon on the evening of the 2nd. If you have binoculars or a small telescope, point them toward Venus, but only after the Sun has set! You’ll be rewarded with a glimpse of the planet as a very thin crescent, which should be almost identical to the phase the Moon displays when the two objects share the limelight.

As Venus leaves the sky giant Jupiter asserts his role as lord of the night. Old Jove reaches opposition on the 5th at 4:11 pm EST. At this time Earth passes directly between the Sun and Jupiter and the planet rises at sunset and sets at sunrise. This is also when the giant planet is closest to the Earth, and a telescope will show his disc at a generous 46.8 arcseconds’ apparent diameter. In smaller instruments look for the planet’s four large moons, discovered by Galileo 404 years ago. Their constant shifting configurations are a source of wonder every night. Telescopes of four inches or more aperture will show detail in the parallel cloud belts that mark the jovial weather systems, with larger instruments revealing more details. If you happen to catch the Great Red Spot crossing the disc, keep in mind the fact that this feature has a surface area that’s equivalent to the entire surface area of the Earth!

Ruddy Mars now rises shortly after midnight and is still best placed for viewing at the onset of morning twilight. The red planet is drifting eastward among the stars of Virgo, and by the end of the week he’ll be about 10 degrees northwest of the bright star Spica. Mars is wending his way toward opposition in April, but as the Earth catches up to him his apparent disc is gradually growing and he is gradually brightening. Owners of larger telescopes should be able to discern some detail on his dusty face.

Finally, it’s time to start mentioning far-flung Saturn. The ringed planet may now be found in the southeast as morning twilight begins. He’s located in the obscure zodiacal constellation of Libra, the Scales, forming a triangle with the constellations two brightest stars, Zubenelgenubi and Zubeneschamali. If you catch a glimpse of him before twilight interferes you’ll be rewarded with a view of his wide-open rings.