In the Sky Tonight
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Thursday, September 29, 2005
Looking East One Hour Before Dawn
Here's a view of the waning crescent moon in early morning -- near the constellation Leo the Lion.
The brightest star in Leo is Regulus, a blue-white star located some 85 light-years away. Regulus is located at the bottom tip of a noticeable pattern within Leo -- an "asterism" called The Sickle -- which appears on our sky's dome as a backwards question mark. In ancient skylore, this Sickle pattern represents the head and shoulders of Leo the Lion.
There is another bright star in The Sickle. It's Algieba, located about 110 light-years from Earth, known to stargazers with telescopes as a double star system. Both stars in the Algieba system are yellow giants. The distance between the two stars is about four light-hours, about the same distance as that between our sun and its planet Neptune.
Neptune orbits our sun in 165 years, however, while the two mighty suns in the Algieba system move through space more slowly. Estimates regarding the length of their mutual orbit vary from around 400 to around 600 years.
Also in the predawn sky, higher up in the horizon is the farthest of the five easily visible planets to the unaided eye, the planet Saturn. The other four are Mercury, Venus, Mars, and Jupiter.
I say "easily visible" because people who can see large stars in the sky can easily view them. The planet Uranus is theoretically visible to the naked eye...but it's never easy to see with the eye alone. ItÂ’s certainly possible to see Uranus with the eye, but you need a very dark sky to do it.
Uranus reached its opposition at the beginning of this month, which makes right now a good time to try to see it. You can find Uranus, which is currently located in the constellation Aquarius, up in the southeast shortly after sunset. -
Thursday, September 29, 2005
Looking Northeast After Sunset
Cassiopeia the Queen can now be found high in the northeastern sky after sunset. This constellation has the distinct shape of a W, or M, depending on your perspective.
The stars of the queen are quite luminous -- its stars Schedar, Caph, and Gamma Cas 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 on the famous M (or W) constellation shape in brightness with a third magnitude rating.
However, there is an intriguing star, often overlooked by skywatchers as it is not a part of the traditional letter-shaped part of the Queen. It is a fourth magnitude star, located slightly off the M (or W) between the alpha star Schedar and Gamma Cas. It's name is Eta Cas, and it is particularly of interest to astronomers because of its similarity to our sun. Eta Cas is similar in color, size, and temperature to our own sun. In fact, if we could somehow travel to Eta Cas (which is a relatively scant 19.4 light years away) and catch sight of our own sun, it would look very much like how Eta Cas looks in our skies now. -
Thurdsay, October 6, 2005
Looking Southwest After Sunset
This evening, turn your gaze towards the lower southwestern horizon and you will see our bright sister planet, Venus shining strongly against the evening twilight. If you look to the lower right of Venus, you will notice the slim sliver of the waxing crescent moon. Venus and the crescent moon will have only have three more such close encounters with each other during the rest of VenusÂ’ current apparition in our evening skies. The next one will occur about a month from now on November 5th. Now, if you sweep your eyes to the left of the moon and Venus, you may catch sight of a smaller, but luminous reddish object. This little jewel is the star Antares, alpha star of the constellation Scorpius the Scorpion. -
Friday, October 7, 2005
Looking Southwest After Sunset
Today's chart is aimed southwest. The time is in early evening. At this time of night, the brightest objects in this part of the sky are the planet Venus and the star Antares in the constellation Scorpius the Scorpion. Tonight Antares appears very close to a thickening waxing crescent moon. Yesterday morning (or yesterday afternoon for those in the U.S.), Antares appeared so close to the moon, that in some locations across the globe (central Pacific Ocean, West Samoa, and the western tip of northern South America) the moon appeared to occult, or pass in front of the reddish star Antares. This morning occultation is pretty difficult to see, and perhaps should be left to seasoned astronomers. Those of us in all the other areas of the world, take heart -- Antares is occulted by the moon approximately once every 27 days throughout the rest of this year and on into the next. The best chance for those of us in North America to witness the moon occulting Antares will come up around the end of December this year. -
Captured on 7 Oct 05
The crescent moon and Venus in the western night sky
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Captured on 7 Oct 05
Close-up of the crescent moon and Venus in the western night sky
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Thursday, October 13, 2005
Looking Southeast Before Dawn
Tomorrow morning before the sunrise, the planet Saturn can be found above the southeastern horizon, along with a beautiful and prominent pattern of stars. The brightest star in the southeast before dawn is the greater Dog Star Sirius in the constellation Canis Major. Saturn is located to the left of Sirius in the predawn sky, along a graceful line that includes the first magnitude star Regulus, also known as the "Heart" of the constellation Leo the Lion, plus two stars noticeable because of their close placement to one another. These are the "twin" stars Castor and Pollux of the constellation Gemini. Almost directly to the right of Saturn is the lesser Dog Star Procyon from the constellation Canis Minor. -
Friday, October 14, 2005
Looking Southeast Before Dawn
You may recognize this pattern from yesterday's chart -- it is set at the same time and place in the sky. Today we wanted to point out the famous Beehive Cluster now located above Saturn. This star cluster is best seen in a very dark country sky (although it can be glimpsed with binoculars from the suburbs). In a dark sky, it appears as a fuzzy patch to the eye alone. A small telescope shows about 50 stars here, but astronomers know that the Beehive actually contains some 400 stars. The cluster is 15 light-years across, and is located about 500 light-years from Earth. -
Friday, October 14, 2005
Looking Overhead in the Northwest at Nightfall
We get many questions from people in northern latitudes about if and when they can view the Southern Cross asterism in their portion of the sky. The truth is that unless you live close to the equator (Hawaii, or the southernmost parts of Texas or Florida for those of us in the U.S.), you will not be able to view this famous asterism, also known as the constellation Crux. We in the northern half of the globe have its less renowned, but elegantly beautiful cousin rising high in our skies tonight. The star Deneb on today's chart identifies the top of the astronomical grouping called the Northern Cross. Unlike its southern counterpart, the Northern Cross asterism is a clipped version of another constellation Cygnus the Swan, which you can find high in the northwest at nightfall. -
Wednesday, October 19, 2005
Looking East-Northeast in Early Evening
Today, the moon has moved eastward in its path across the sky, as it always does. It's now less than one degree from the famous Pleiades star cluster. Wait a day or two as the moon moves on from the sky, and you can easily recognize this cluster as a tiny dipper shape. In fact, a lot of skywatchers comment on the fact that the Pleiades cluster looks more like a dipper than the Big Dipper. Most people see just six stars here, and, because this cluster is sometimes called The Seven Sisters, there's a persistent question in skylore about the whereabouts of the so-called Lost Pleiad. People with superior vision have been known to see more stars in the Pleiades with the naked eye -- up to 16 stars have been reported in recent centuries. Modern photographs show thousands of stars in this vicinity, but only about 250 of these are thought to be true, gravitationally bound members of the Pleiades star cluster. -
Friday, October 21, 2005
Looking West-Southwest Before Dawn
The Orionid meteor shower radiates, or appears to come from the constellation Orion the Hunter, which is now easy to see in the southwestern sky before dawn. YouÂ’ll know youÂ’ve found Orion if the midsection of the pattern you see consists of a short, straight row of three medium-bright stars -- known as OrionÂ’s Belt. Tomorrow morning is peak viewing time for this major annual meteor shower. Unfortunately, a rather large waning gibbous moon appears in this area of the sky now, making this yearÂ’s display difficult to view for novice meteor enthusiasts. The best time to watch is between the hours of midnight and dawn. For more about this yearÂ’s Orionid meteor shower, check out Gary KronkÂ’s meteor pages. Also up in the west-southwestern before dawn is our red neighbor planet Mars. -
Saturday, October 22, 2005
Looking West-Southwest One Hour Before Dawn
The constellations are made of stars in various patterns, and so, to identify them, you'll want to look for noticeable patterns on the sky's dome. An easy one to find now is the constellation Orion the Hunter. You'll find it due to its very noticeable pattern of three medium-bright stars in a short straight row. These stars represent Orion's Belt. The Hunter is in the west-southwest before dawn at this time of year. You can use the famous “Belt” stars -- Alnitak, Alnilam and Mintaka -- as a pointer to other bright stars. If you draw an imaginary line through Orion's Belt, you'll see that it points in one direction to the reddish star Aldebaran, which lies in a V-shaped pattern of stars representing the Face of the Bull in the constellation Taurus. The same line drawn through Orion's Belt points in the other direction to Sirius, the sky's brightest star, in the constellation Canis Major. And that's how you come to know the constellations -- by using what you've already learned to "build" outward to find new patterns. -
Saturday, October 22, 2005
Visualization: West Southwest at Sunset (Do not look directly at the sun!)
Just last month, we were hearing from a lot of people who were glimpsing Jupiter making lovely patterns with Venus, and the star Spica in the west after sunset. Shortly after, this giant planet made its way towards the horizon in late afternoon, becoming lost in the sunset glare. Since that time, it has been blocked from view for us. From a three-dimensional perspective, Jupiter was traveling on the far side of the sun from Earth. Its “conjunction” with the sun comes today, meaning that the sun is now between our planet and Jupiter (as viewed by us). Later on this year, it’ll come back to the eastern sky before dawn. When can you expect to see Jupiter next? By late November, it’ll be only 10 degrees above the east-southeastern horizon before dawn at the beginning of morning twilight. Jupiter is so bright that you should be able to glimpse it then. -
Tuesday, October 25, 2005
Looking South-Southeast One-Two Hours Before Dawn
We're looking south-southeast in the hour before dawn. The moon has pulled eastward of Castor and Pollux in the constellation Gemini, and is now near the planet Saturn, which is currently located in the constellation Cancer the Crab. Saturn takes about 30 Earth-years to complete one orbit around the sun. That's in contrast to Mercury's orbit of 88 days . . . or Venus' orbit of 225 days. . . Earth's of 365 days. . . Mars' orbit of about two Earth-years . . . or Jupiter's orbit of about 12 Earth-years. So, Saturn moves slowly in front of the stars, which is why some early stargazers called it by a name than means "oldest of the old sheep." Saturn has been in the constellation Cancer since last month. -
Wednesday, October 26, 2005
Looking South-Southeast One-Two Hours Before Dawn
From yesterdayÂ’s chart, youÂ’ll see that the now first quarter moon has moved eastward in the sky, as it always does, leaving Saturn and the constellation Cancer the Crab behind. Cancer is the faintest of the 12 constellations of the zodiac. You won't see much of this constellation with the eye alone, but some people describe Cancer's shape as resembling the spokes of a wheel. If you wait a day or two (when the moon is out of this area of the sky), you can aim your binoculars in this direction to see one of the sky's best hidden treasures. It's a cluster of stars called M44, otherwise known as Praesepe or the Beehive Cluster, and it's right in the middle of the Crab. As usual, the darker your night sky, and the farther you are from city lights, the better the view. -
Thursday, October 27, 2005
Sweeping Your Gaze Due South - Due East Before Dawn
If you're looking for the moon, you won't find it until early tomorrow morning. You will find the waning crescent moon rising in the eastern sky around 2 or 3 a.m. (depending on how far east or west you are in your time zone). It appears about three degrees to the left of the star Regulus on the sky's dome. This star -- whose name means "little king" -- is the brightest light in the constellation Leo the Lion. Regulus is located some 77 light-years away. Notice the backwards question mark pattern -- Regulus marks the bottom tip of the question mark. This pattern is an "asterism" -- or noticeable pattern of stars -- within the constellation Leo. It's called the Sickle, and it represents the head and shoulders of the Lion. Another bright star shining in that vicinity, towards the south, is Sirius of the constellation Canis Major, which happens to be the brightest shining star in our skies! -
Thursday, October 27, 2005
Break out your binoculars and aim your gaze towards the southwestern horizon this evening just after the sun sets, and see if you can spot the lovely formation in today's chart. First locate a bright object towards the south-southwest, the planet Venus. It will be the easiest to locate as it is the brightest of the three. Once you have Venus in your sights, turn your gaze diagonally towards the lower right, and see if you can spot the reddish-hued star Antares from the constellation Scorpius the Scorpion. Once you've spotted Antares, turn your aim to the lower right of it, and see if you can spot a white Mercury against the evening twilight. This is not an easy feat -- this evening appearance of the planet Mercury is one of the poorest for us in the northern hemisphere this year. Mercury will be visible in this way for the next several days, but come the first week of December, Mercury will be more easily visible in morning for those of us in the northern half of the globe. -
Friday, October 28, 2005
Glimpsing deep space Looking East One Hour After Sunset
You can spot the most distant object visible to the unaided eye -- the Great Galaxy in the constellation Andromeda -- on any evening this month and next. To help you locate it -- here is a view of the constellation Andromeda the Princess -- as well as the Great Square in the constellation Pegasus the Flying Horse. This galaxy is also known as M31 and it's the next-nearest galaxy to our Milky Way. The constellations Pegasus and Andromeda share a star (officially it belongs to Andromeda) -- the star Alpheratz -- which marks one corner of the Great Square. The rest of the constellation Andromeda extends in two graceful streams of stars from Alpheratz. And once you find the constellation Andromeda, finding the Andromeda galaxy isn't difficult -- IF you have a clear, dark country sky. Also up in this vicinity of the sky is the planet Mars, which reaches its closest point to Earth tomorrow! -
Sunday, October 30, 2005
Looking East After Sunset
Yesterday, Earth caught up to Mars in its shorter, faster orbit around the sun. Because we orbit the sun one step inward, our planet Earth moves faster than Mars in orbit. We move at about 18 miles per second, in contrast to 15 miles per second for Mars. Thus, every two years, Earth catches up to Mars in orbit and passes between the red planet and the sun. Earth will pass between the sun and Mars on November 7th this year. This event is called an "opposition" of Mars. At opposition, Mars rises at sunset and appears in our sky all night, at its closest and brightest for that two-year cycle. Click here for a wonderful animation that depicts the orbits of Earth and Mars in this cycle. -
Tuesday, November 1, 2005
Looking Due South After Midnight
Earth has now caught up to Mars in its shorter, faster orbit around the sun. Our planet will fly between Mars and the sun on November 7th, thus creating what astronomers call a "Mars opposition." In the meantime, this orbital activity has brought us very close to Mars, and so now is a prime time to break out the telescope and binoculars to try to get some spectacular views of the red planet. The best time to see details of Mars is when it is at its highest in the sky -- right now that's after midnight in the south. It's true that Mars doesn't have obvious features like Saturn's rings or Jupiter's spot, but it should be possible to pick out dark and light markings that adorn the Martian surface. -
Tuesday, November 1, 2005
Looking East-Northeast in Early Evening
About an hour after sunset, if you're looking in a dark-enough sky, you can spot the tiny constellation Aries the Ram in the east-northeast in early evening. Maybe you can spot it in relationship to the W-shaped constellation Cassiopeia the Queen, and the planet Mars, and the tiny misty dipper-shaped Pleiades star cluster. Aries isn't conspicuous. And yet, in newspaper astrology columns, Aries often comes first in lists of constellations of the Zodiac. These are the constellations that provide a backdrop for the sun, moon and planets in the course of every year. It's traditional to place Aries first on this list because it marked the sun's location at the time of the vernal equinox between about 1800 B.C. and 1 A.D. This point in our sky retains this name, even though the actual location of the sun at the time of the vernal equinox has shifted into what astronomers now recognize as the constellation Pisces. It's moving, due to the Earth's motion of "precession." This point in our sky -- where the sun is at the vernal equinox -- is still moving. -
Wednesday, November 2, 2005
Looking East-Northeast in Early Evening
Go back to yesterday's chart for the location of the constellation Aries the Ram with respect to other stars in the east-northeast in early evening. Here's a close-up view of this tiny, but significant constellation. Aries is small, but it's really pretty easy to find. We see it as three stars. Hamal and Sheratan are of medium-brightness. Mesarthim is fainter. Sheratan and Mesarthin marked the location of the vernal equinox about 2,000 years ago. You might try to find Aries tonight in relationship to the tiny dipper-shaped cluster Pleiades and the planet Mars. As always, a dark sky will enhance the view! -
Friday, November 4, 2005
Looking Southwest After Sunset
You can find our sister planet Venus low in the southwest against a backdrop of bright evening twilight. The further south you are located on the globe, the better your chances of seeing Venus right now, though all locales would benefit from an unobstructed western view of the sky. By the end of this month, Venus will be setting more than two and a half hours after sunset, giving those skywatchers in the north an even better shot at seeing her. We have included in the chart the position of the young waxing crescent moon located to the lower right of Venus. If you happen to own a pair of binoculars, you may be able to pick out the young crescent shape against the evening twilight -- and if you turn your gaze to the lower right -- you might catch the planet Mercury near the horizon. -
woot.. nicee
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Saturday, November 5, 2005
Looking Southwest After Sunset
If you take a look back at yesterday's chart, you'll see that the moon has moved eastward in the southwestern sky and is now located a couple of degrees to the right of the crescent waxing moon. The further south you are located on the globe, the better your chances of seeing Venus right now, though all locales would benefit from an unobstructed western view of the sky. If you happen to own a pair of binoculars, you may be able to pick out the young crescent shape against the evening twilight -- and if you turn your gaze to the lower right -- you might catch the planet Mercury near the horizon.