In the Sky Tonight

last SG · 2005-08-23T14:26:28+00:00

Spotting the Summer Triangle Wednesday, May 17, 2006 Looking East-Northeast in Late Evening In the east-northeast in late evening, you'll find a famous...

poon cho tang SG

Eastern stars in mid-evening

Thursday, December 29, 2005

Sweeping Your Gaze Over the Eastern Horizon at Mid-Evening

Todays chart shows a wide view of the east in mid-evening. Sirius, the brightest star in our skies, is just above the southeastern horizon at this time. Making a sharp angle to its upper left is its companion dogstar Procyon. To the upper left of Procyon is a familiar pair of stars -- the Twin stars Castor and Pollux of the constellation Gemini. To the upper right of bright Sirius is the star Rigel of the constellation Orion the Hunter. The bright object almost directly left of Rigel is Betelgeuse, also of Orion. Located above those two stars is the reddish-star Aldebaran -- brightest star of the constellation Taurus the Bull. The flashing star Capella of the constellation Auriga the Charioteer can be found to Aldebarans upper left. The planet Mars tops this celestial bevy of stars in the southeast with its red-tinged brightness.

poon cho tang SG

Second new moon this month

Friday, December 30, 2005

Looking Southwest Before Sunset

Don't expect to look westward this evening and see this ghostly moon near the sun. The image shows up fairly well on a computer screen -- but it won't show up at all in the real sky -- and you should never look toward the sun without a protective filter. Today's chart is purely an illustration of the fact that the moon is new today. That means it's passing between the Earth and sun as these bodies move in space. Thus, although the moon is near the sun in the sky today, you won't see the moon anywhere in today's sky. There are two reasons why. First, the moon's lighted face -- its "day side" -- is turned entirely away from us now. Also, the moon is hidden in the sun's glare. As the moon moves eastward in orbit around Earth, it'll edge slowly away from the sun on our sky's dome. Today's new moon marks the second for this month (the first being on December 1st). Thus, this month has completed a full lunar cycle from start to finish.

poon cho tang SG

Stars in other galaxies

Saturday, December 31, 2005

Looking West-Northwest in Late Evening

"Are there any stars outside our own galaxy that we can see with just the eye?"

The answer is no -- unless you count seeing the combined light of many billions of stars. From the northern hemisphere, the only galaxy outside our Milky Way that's easily visible to the eye is the Great Galaxy in the constellation Andromeda. In January, this galaxy is in the west-northwest each evening. You need a very dark country sky, on a night like tonight when there's no moon, to be able to look up and notice the galaxy without consulting a chart. It'll appear as a hazy patch in the night sky, as wide in diameter as a full moon. And, indeed, this haze represents the light of the Andromeda galaxy's billions of stars. But we still can't see individual stars within this galaxy -- not with the eye alone. Even with amateur telescopes, the patch of light that we see as the Andromeda galaxy looks, at best, like haze.

poon cho tang SG

Venus near moon tonight

Sunday, January 1, 2006

Looking Southwest Shortly Before Sunset

Todays chart is set for shortly after sunset tonight in the southwest. A very slim crescent moon can be spotted just a few degrees to the left of the planet Venus. As the moon and Venus sink into the western horizon along with the evening twilight, a few stars can be spotted in that area. You can spot the star Altair of the constellation Aquila the Eagle due west. Altair is one of a triad of stars that make up the famous Summer Triangle now visible in the west in early evening. In the south-southwest you can spot the Loneliest Star Fomalhaut of the constellation Piscis Austrinus. It's said to be "lonely" because it's noticeable as the only bright object in an otherwise empty region of the sky.

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"River of stars" visible in southeast

Monday, January 2, 2006

Looking East-Southeast at Nightfall

If you have access to a dark country sky, you can see Eridanus, the constellation of the River. You won't see this one from the city, or even the suburbs. Eridanus the River begins near the star Rigel in the constellation Orion -- and wells up in a great loop before ambling back down toward the southern horizon. Eridanus is one of the longest and faintest constellations. It's variously said to represent the Nile, Euphrates or the River Po. It's also sometimes called the River of Orion. From most of the U.S., the River disappears below the southern horizon. But if you live at a very southerly latitude you can see a special sight -- the star that represents the end of the River.

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Star at "End of the River"

Tuesday, January 3, 2006

Looking South-southeast at Nightfall

Today's chart is almost just like yesterday's chart. But today we've changed our observing location to more southerly latitudes in the northem hemisphere. It's only if you're farther south on Earth's globe, that you can see the famous star that marks the End of the River. This celestial River is called Eridanus. The star marking the End of the River star is very bright! But bright or not, you'll never see it anywhere but right next to the southern horizon if you're observing from the U.S. And you won't see it at all from the northern states. That's because this star is located very far to the south on the celestial sphere, the imaginary dome of stars surrounding Earth. This star makes only a tiny arc above the southern horizon from the more southerly latitudes, so you have to be looking at just the right time to see it . . . for example, tonight around 8 p.m. The star's name is Achernar. If you see it, you'll never forget it!

poon cho tang SG

Finding the North Star

Wednesday, January 4, 2006

Looking North-Northeast in Late Evening

There is a neat trick to finding the North Star, also known as Polaris, in the night sky. That is, your latitude gives you its height above the northern horizon. In other words, if your latitude is 30 degrees, then the pole star is 30 degrees above the northern horizon. From a latitude of 40 degrees N., it is 40 degrees up -- and so on. Polaris can be seen at any time of night. But, at this time of year, you might want to wait until around midnight to look for it -- so you can use the Big Dipper as a guide. The two outer stars in the bowl of the Big Dipper point to Polaris.

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Latest sunrises this week

Thursday, January 5, 2006

Looking East-Southeast at Sunrise

Today's chart shows the eastern sky shortly before sunrise . . . the last object to fade from view in the east before dawn is the planet Mercury. The sun rises very late in early January. The exact date of latest sunrise varies with latitude, but the sequence never varies: the earliest sunsets come in early December, the shortest day comes on the winter solstice around December 21, and the latest sunrises come in early January. For 40 degrees N. latitude (a line that runs approximately through the vertical middle of the U.S.) , January 5 is the date of latest sunrise. The reason it happens is complicated. Here's how sky guru Guy Ottewell explains it: "The reason why earliest/latest sunrise/set do not coincide exactly with the solstices is the slight eccentricity of the Earth's orbit. While rotating at essentially constant speed, Earth is traveling faster around its orbit at some times (Jan.) than at others (July), thus changing its angle with respect to the sun at different rates."

poon cho tang SG

Saturn and company

Friday, January 6, 2006

Looking East in Late Evening

Here is the view of the eastern horizon at late evening. The planet Saturn can be found amidst a smattering of bright stars. Most notable among them is the twin luminaries Castor and Pollux of the constellation Gemini, the bright dogstar Procyon of the constellation Canis Minor, and the glowing red giant sun Betelgeuse of the constellation Orion.

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Ram constellation near moon tonight

Saturday, January 7, 2006

Looking Southwest at Nightfall

A couple of hours after sunset, if you're looking in a dark enough sky, you can spot the tiny constellation Aries the Ram. You'll find this constellation in the southwest in early evening. Aries isn't conspicuous -- but tonight the Ram will reside by two great celestial markers -- the moon and the bright red planet Mars. We see it as three stars. Hamal and Sheratan are of medium-brightness and so will be the easiest stars to view. Sheratan marked the location of the vernal equinox about 2,000 years ago.

poon cho tang SG

Moon in the daytime

Sunday, January 8, 2006

Looking East in Mid-Afternoon

Heres the daytime moon, as you might see it in the eastern sky in mid-afternoon . We have gotten this question: I have seen both the sun and moon during a day. How does this happen? The moon orbits around Earth once a month. Once each month, it comes nearly in between the Earth and sun . . . and at such times the moon rises with the sun and travels across the sky all day long. As it moves in its orbit, the moon gets farther from the sun on our sky's dome. It moves toward the east in our sky by about 12 degrees (about the width of your fist held at arm's length) each day. After two weeks, the moon is about 180 degrees from the sun. Then its on the exact opposite side of the sky's dome from the sun. When the sun goes down in the west, the full moon rises in the east. Now were a couple of days past full moon. The moon -- still moving eastward -- has moved more than 180 degrees opposite the sun . . . now its beginning to move closer to the sun again on the skys dome. At that time youll see the moon higher in the west each morning for the next several days.

poon cho tang SG

"Hands" of Big Dipper, Queen

Monday, January 9, 2006

Looking North-Northeast in Late Evening

The Big Dipper and the constellation Cassiopeia the Queen are like the hands of a clocks, wheeling around eternally in the northern sky. The Big Dipper is an "asterism" . . . or noticeable pattern of stars . . .within the constellation Ursa Major the Greater Bear. The Big Dipper can be used to find Polaris, the North Star. Simply look in the sky, and draw an imaginary line between the two outermost stars in the Dipper's Bowl. This line points to Polaris. Keep that line going . . . and you will come to another famous constellation Cassiopeia. The Queen is very recognizable for having the shape of the letter "M" or "W," depending on what time of year and what time of night you see it. At this time of year, the Big Dipper is in the northeast in late evening, and Cassiopeia is in the northwest. These two constellations are "circumpolar" -- as seen from northerly latitudes, they never set. They circle endlessly around the North Star, are always opposite each other. In other words, when the Dipper is at about 4 o'clock -- as it appears on today's chart -- then Cassiopeia must be at about 10 o'clock -- using the North Star as the clock's middle.

poon cho tang SG

Queen in close view

Tuesday, January 10, 2006

Looking North-Northeast in Late Evening

Look back to yesterday's chart to find out how to identify the constellation Cassiopeia the Queen in the night sky. In the lore of the sky, Cassiopeia was a very vain queen of Ethiopia, mother to the lovely princess Andromeda. She claimed to be more beautiful than the Nereids, or sea nymphs. And so the gods placed her in the heavens so that she'd be upside-down for part of every night and part of every year. Tonight, if you look, the stars of Cassiopeia will be oriented in such a way that the Queen is upside-down. The stars of the queen are quite luminous -- its stars Schedar, Caph, and Gamma Cass all have approximately mid-second magnitudes. The star Ruchbach is close in brightness to them, with a magnitude of about 2.68. Segin trails the other stars in brightness with a third magnitude rating. Also be sure to sweep in this area with binoculars if you have access to a clear, dark, country sky. You'll see many hazy patches in this region, which are often open star clusters in our own Milky Way galaxy. A particularly easy one is M52, marked on today's chart. M52 looks like a hazy clump, but it's actually a cluster of some 200 stars, spanning about 15 light-years. This cluster lies an estimated 5,000 light-years away.

poon cho tang SG

Fiery eye of Bull near moon tonight

Wednesday, January 11, 2006

Looking South-Southeast in Early Evening

Today's chart is once again set in the south-southeast in early evening. You can see the fiery red star Aldebaran to the lower right of the now waxing gibbous moon. This star is part of a V-shaped grouping of stars that represent the face of the constellation Taurus the Bull. Aldebaran -- known as the fiery "eye of the Bull" -- is a giant star, some 45 times bigger in diameter than our sun. In other words, if Aldebaran replaced our sun in the solar system, its outer layers would extend halfway to the orbit of the innermost planet in our sun's family, Mercury. Another fiery red object is up in the south at this time-- the planet Mars.

poon cho tang SG

Hyades star cluster

Thursday, January 12, 2006

Looking South-Southeast in Early Evening

Tonight, look for the Hyades star cluster -- not just a pattern on our sky's dome -- but an actual, gravitationally bound cluster of stars in space. You can find it in the south-southeastern horizon to the lower left of the planet Mars. To the eye, the Hyades appears to be shaped like the letter V (you'd see many more stars if you looked through binoculars or a telescope). On the sky's dome, this V represents the face of Taurus the Bull. In the lore of the sky, the Hyades are half-sisters to another cluster of stars -- the dipper-shaped Pleiades star cluster. The reddish star Aldebaran appears to be a part of the V-shaped Hyades cluster. However, at about 60 light-years away, Aldebaran is only about half the distance to the Hyades star cluster in space -- and not so not a true part of the cluster.

poon cho tang SG

Venus reaches inferior conjunction today

Friday, January 13, 2006

Visualization Only -- Looking West-Southwest Before Sunset

Today the planet Venus will not be seen in the night sky. It reaches what is called its "inferior conjunction." That is when an interior planet (Mercury or Venus) passes between the Earth and the sun. It is rare to see an inferior conjunction because the sun is usually too bright and thus drowns out our view of the planet (the June 2004 transit of Venus being a notable exception.) Today's inferior conjunction is no exception. Thus, today's chart is not meant for viewing (please don't ever look directly at the sun!) It is meant for visualization purposes only.

poon cho tang SG

Sighting Stardust

Sunday, January 15, 2006

Looking Westward in the Early Morning Hours

Here is a view of the western sky in the early morning hours of January 15th. U.S. observers in or near the state of Nevada may catch a strange unexplained point of light in the sky near the full moon at approximately 3 a.m. MST. Some may mistake it for a meteor or a UFO -- but it is an actual identified object. It is the return of the Stardust spacecraft capsule, sent out two years ago by NASA to collect and bring back comet particles from the comet Wild 2.

poon cho tang SG

Meteor hunting

Monday, January 16, 2006

Looking Westward in the Early Morning Hours

Todays chart is identical to yesterdays. About a week from now when the moon is smaller and less present in early morning skies, will be a great opportunity to look for random meteors. We get lots of questions about where and when to catch meteor showers. To everyone who longs to see a shooting star or meteor streaking across a clear night sky . . . its possible to see a meteor any night of the year. Just recently on a holiday trip to Timberon, New Mexico, I spotted a minimum of 3-4 meteors each night just randomly gazing up in the sky. There are dozens of minor meteor showers, and also random meteors appearing in our skies that arent associated with any shower. But, not all of us have the chance to be in a dark mountain or country area -- and so its true that youll have the best chance to see meteors on nights when a major meteor shower reaches its peak. You can always check Sky & Telescope magazines great web site or Gary Kronks page to learn about upcoming meteor showers. The next best time to watch for meteors would be in mid-late April, when the Lyrid meteor shower will be in full swing (though a waning gibbous moon may drown out any spectacular views). One further tip -- youll see more meteors after midnight than before, when Earths spin will place you on the forward side of the planet with respect to our orbit around the sun.

poon cho tang SG

Moon in Lion tonight

Monday, January 16, 2006

Looking East-Southeast in Late Evening

Today we are looking at the same area of the sky as yesterday's chart, but at a different time -- in late evening. Thus todays chart, though it essentially contains the same information as yesterdays, is set in the east-southeast. Todays chart shows a closer view, so that you can identify not only the planet Saturn, but also the stars in the constellation Leo the Lion. At least try to pick out Regulus, Leos brightest star and Denebola, the star representing the Lions Tail.

poon cho tang SG

Southeastern evening highlights

Tuesday, January 17, 2006

Looking Southeast In Early Evening

Todays chart is set in the southeast in the early hours of nightfall. In this area of the sky, people have been catching sight of a brilliant point of light, flashing green and red near the southeastern horizon. This is none other than the dogstar Sirius of the constellation Canis Major. Above Sirius is one of the most easily recognizable and beautiful of constellations -- the constellation Orion -- easily spottable by its famous Belt of three bright stars. Towards the upper left of Orion is the bright star Capella of the constellation Auriga the Charioteer. To the upper right of Orion are two bright red lights -- the star Aldebaran and the planet Mars (which has noticeably waned in brilliance since last November.) Sandwiched between the two red lights is the Pleaides star cluster, known for its striking dipper-like appearance.

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