Mars is less than one month away from its March 3, 2012 opposition when it will be best for this two-year period. Let the moon show you Mars tonight!

On the night of February 9, 2012, the moon, Mars and the constellation Leo the Lion are seen together over the eastern horizon about two to three hours after sunset. Regulus, Leo’s brightest star, rises first at nightfall or early evening. Then the moon and Mars follow Regulus into the sky some 60 to 90 minutes later. The moon might look full to you, but it’s really now in a waning gibbous phase. Does Mars look reddish to you in the moon’s glare?

The fainter stars of Leo might be hard to make out in the lunar glare tonight, but Regulus, Leo’s brightest star and one of the brightest stars in our night sky, will be easy to spot. Mars beams even more brilliantly than Regulus, and is found near Denebola, the star that depicts “the Lion’s Tail.”

Regulus: Lion Heart

Venus and Uranus remain within one binocular field for the next several evenings, though Venus climbs upward, away from Uranus.

But wait. Back up – and now think western sky, not eastern sky. Before the moon rises tonight, on February 9, 2012, look westward as darkness falls for the dazzling planet Venus, the brightest starlike object in the starry sky. If you have binoculars or a low-powered telescope, aim them at Venus to catch the faint planet Uranus nearby. From mid-northern latitudes in North America, Uranus will appear to the immediate left of Venus, or as seen from Asian mid-northern latitudes, Uranus will be to Venus’ upper left. Venus and Uranus will occupy the same binocular field of view for the next several evenings, though Venus will climb a little higher above Uranus with each passing day.

At roughly the time that Venus and Uranus set – or around three hours after sunset – the Regulus/moon/Mars trio begin their ascent in the east.

Mars is a planet and moves in front of the star background, making a beeline around the entire sky – through all the constellations of the Zodiac – once every two years. Leo’s stars, like all stars, are much more steadfast. They rise four minutes earlier each day, or two hours earlier with each passing month. Sometime in March 2012, watch for Leo to light up the eastern sky as soon as darkness falls – a sure sign that spring is about to return to the Northern Hemisphere.

Like the sun, the stars of Leo the Lion swing full circle across the sky once a day. This movement is due to Earth’s spin under the sky.

Unlike the sun, however, the stars return to the same place in the sky in 23 hours and 56 minutes – not 24 hours. This is happening because – as Earth spins – it’s also moving through space, in orbit around the sun. And as we move, our night sky points out a constantly changing panorama of the Milky Way galaxy.

The 4-minute difference between the return of the stars (sidereal day) and the sun (solar day) may seem insignificant, but this discrepancy adds up over time. Because of it, we associate certain stars with certain seasons of the year. If the stars returned to the same place in the sky every 24 hours, we wouldn’t have seasonal constellations.

In short, all the stars rise about 4 minutes earlier with each passing day. One and one half months from now – around the March 20 equinox – the stars of Leo the Lion will rise some 3 hours earlier than they do tonight.

How do we know about our galaxy’s shape?

Bottom line: Look for the moon, Mars and stars of Leo the Lion in the east about two to three hours after nightfall. Then watch for these Leo stars and Mars to appear above the eastern horizon as soon as darkness falls sometime in March. Mars is now nearly at its best for this two-year period. Its opposition – when Earth flies between Mars and the sun – will come on March 3, 2012.

Starting today – on February 8, 2012 – Saturn will begin to go in a retrograde or westward direction in front of the constellation Virgo. That’s a signal that the best time to see Saturn in 2012 has begun.

Give me 5 minutes, and I’ll give you Saturn in 2012

The planet Saturn – a golden world that appears to shine steadily on the sky’s dome – is rising in the east somewhere around 11 p.m. to midnight. Saturn climbs upward through the night and soars to its highest point in the southern sky around 5 a.m. The beginning of retrograde motion means that Saturn will be rising earlier each evening with each passing day. It’ll soon be in a more convenient place for evening viewing.

The moon, Regulus and Mars low in the east at mid-evening.

If you don’t want to stay up so late, you can still see plenty of planets this early evening. Dazzling Venus and Jupiter pop out first thing at dusk. And if you have binoculars, you can spot Uranus close to Venus at nightfall. Look for the red planet Mars before bedtime, as it rises above the eastern horizon around 9 to 10 p.m., as shown on the sky chart on the right. We’ll tell you about these early evening planets on tomorrow’s show, but for the meantime, we return to Saturn and its retrograde.

Rising time for Mars and Saturn in your sky

Some four-and-a-half months from now – on June 26, 2012 – Saturn’s retrograde motion will end. Then Saturn will still be visible, but its time of best viewing for the year will be over. In other words, after June, Saturn’s maximum brightness for the year will be past. It’ll still be visible, but it’ll seem to have lost some luster.

What’s happening here? As a general rule, Saturn appears to travel eastward in front of the background stars. But you won’t see Saturn moving eastward in front of Virgo again until after June 2012. However, Saturn doesn’t literally change direction. If you think in terms of Saturn’s orbit around the sun, you might enjoy knowing that Saturn always travels in an eastward direction in orbit.

But our Earth in its smaller, faster orbit around the sun is now in the process of passing between Saturn and the sun. We’ll pass between Saturn and the sun on April 15, 2012. Saturn is the 6th planet outward from the sun and moves more slowly than we do in orbit. Saturn now appears to be moving in retrograde – opposite its usual eastward motion – because our planet Earth, like a fast racing car, is now zooming by Saturn from the inside track. You know how, when you’re in a fast car on the highway and you pass a slower car, it can seem to be moving backwards? That’s the case here. As seen from Earth, Saturn will look like it’s moving westward through the stars – even though it’s really not. Isn’t nature cool?

If you want, you can track Saturn’s upcoming retrograde for yourself. Notice Saturn’s present position relative to Spica, the brightest star in the constellation Virgo. Presently, Saturn shines to the northeast of Spica. By the end of its retrograde in late June 2012, golden Saturn will have moved north of Virgo’s sparkling blue-white star. The stunning contrast of color should enable you to distinguish Saturn from Spica all the while.

So the best time in 2012 to see Saturn has begun. Check out this year’s how-to-see Saturn post if you’re not sure how to find it. Or look for Saturn on the nights of February 11 and 12, when it’ll be near the moon. With its retrograde motion beginning today, Saturn will be at its best for about the next four months of 2012.

The moon turns full today (Tuesday, February 7, 2012) at 21:54 Universal Time. That’s 4:54 p.m. EST, 3:54 p.m. CST, 2:54 p.m. MST or 1:54 p.m. PST. The image at top – a February moon from years past – was taken by Dan Bush. His Missouri Skies Moon Page is not to be missed.

Here are the names of all the full moons

This February full moon goes by many different names. The February full moon was called the Snow-blinding Moon by the Micmac people in eastern Canada. It was the Wind Moon to the San Ildefonso of the Southwest. And it was the Blackbear Moon to the Kutenai of the Northwest. Today, in North America, we often call the February full moon the Wolf Moon, Snow Moon or Hunger Moon.

What makes a halo around the moon?

Every full moon stands opposite – or nearly opposite – the sun. Try noticing how high above the horizon you see the moon tonight. Its distance above the horizon indicates approximately how far below the opposite horizon the sun is at that time.

Full moon over Mexico in February 2011. Image Credit: Katie Darden.

Any time you see the moon near the horizon, it might have a reddish color. The reason is Earth’s own atmosphere. The moon’s (or sun’s) light must pass through a greater thickness of atmosphere when rising or setting (that is, when it is near the horizon) than when overhead. Since the atmosphere scatters the bluish component of light, while allowing the redder light to travel straight through to our eyes, objects often appear redder than normal when near the horizon. So any moon, full or not, may look reddish when seen near the horizon.

Regulus, the brightest star in the constellation Leo, shines close to the moon tonight. Watch as Regulus follows the February full moon across the sky tonight from nightfall until daybreak!

Looking for a sky almanac? EarthSky recommends …

The almost-full waxing gibbous moon puts the constellation Cancer in the spotlight – but out of view – this Monday night. Demure Cancer the Crab is the faintest constellation of the Zodiac. You can see it only on dark, moonless nights.

Understanding moon phases

The starry sky is like a great big connect-the-dots book, enabling stargazers to star-hop from brighter stars to more obscure nighttime treasures. For instance, when the moon drops out of the evening sky, starting around mid-February, you can look for Cancer the Crab to show its delicate starlit figure in the region of sky in between the Leo star Regulus and the Gemini stars Castor and Pollux.

Our chart shows the eastern evening sky for North American mid-northern latitudes. But the night sky looks similar at northern latitudes from all around the world. The differences are tiny. For example, tonight the moon’s place in front of Cancer will differ somewhat as seen from around the world. As seen from Europe and Asia, the moon shines closer to Gemini’s stars, Castor and Pollux, and farther away from Regulus, the brightest star in the constellation Leo the Lion. These little differences, as seen from around the world, are due to the moon’s own motion in orbit around Earth.

From the Southern Hemisphere, the differences are due in part to the moon’s movement, and in part to the difference in perspective from one hemisphere to the other. From the Southern Hemisphere tonight, Castor and Pollux appear to the left or upper left of the moon, whereas Regulus is found below the moon or to the moon’s lower right.

Still, we all live under the same sky, and no matter where you live worldwide, the moon beams in front of Cancer tonight, with Castor, Pollux, and Regulus nearby.

Just remember – although we outline Cancer for you on our chart, you’re not likely to see this constellation in tonight’s drenching moonlight. Notice the stars around it, and come back in a week or so to find the faint Crab when the moon has moved on its way – and left the evening sky dark for stargazing.

Beehive cluster: 1,000 stars in Cancer

Tonight, the waxing gibbous moon shines close to Castor and Pollux, the constellation Gemini’s two brightest stars. Although the brilliant moon will obscure much of the starry heavens, Castor and Pollux will probably be able to withstand tonight’s lunar glare.

Gemini? Here’s your constellation

When the moon leaves the evening sky in mid-February, you can use the constellation Orion’s two brightest stars to locate these bright Gemini stars. Draw an imaginary line from the Orion star Rigel through the Orion star Betelgeuse to star-hop to Castor and Pollux. Try this trick tonight. Then try it again on a dark, moonless night.

Blue-white Rigel is at the foot of Orion

Somber red Betelgeuse shines in the shoulder of Orion

In mythology, Castor and Pollux are often portrayed as Twins. However, these two stars are not physically related but reside along the same line of sight by happenstance. Pollux, the brighter star, lies about 34 light-years distance, whereas Castor lodges 52 light-years away.

Moreover, Castor and Pollux are different types of stars. Castor’s white color indicates a hot, youthful star. Pollux’s orange complexion tells us that it’s a cool and oldish star. On this moonlit night, you may need binoculars to discern stellar color.

Why do stars have different colors?

Top tips for using ordinary binoculars for stargazing

Starting at nightfall this Sunday night, you can watch the moon, Castor and Pollux sailing westward across the sky together nearly all night long!

These next two evenings, February 4 and 5, 2012, the moon passes in front of the zodiacal constellation Gemini the Twins. Though the constellation figure won’t be easy to depict in the moonlight glare, you should be able to make out Gemini’s two brightest stars, Castor and Pollux.

Castor is six stars in one

Pollux is the brighter of two Twin stars

Gemini? Here’s your constellation

Moreover, on February 4 and 5, the moon will reside close to its mean distance from Earth: 384,400 kilometers (238,855 miles).

Because of the moon’s eccentric – somewhat oblong – orbit, it’s distance from Earth varies quite a bit from this mean figure of 384,400 kilometers. Not quite a week ago, for instance, the moon swung out to apogee – the farthest point in its orbit – on January 30. It was then 404,323 kilometers away. Yet in about a week, on February 11, the moon will sweep by perigee – the closest point in its orbit – lodging at 367,922 kilometers.

What’s more, even the moon’s mean distance changes over the long course of time. The mean distance is now increasing at the rate of 3.8 centimeters (about 1.5 inches) per year. That adds up to 3.8 meters (about 12.5 feet) a century.

Moon facts at your fingertips

Given that the moon’s distance is increasing, does that mean the moon was closer to Earth in the distant past? Yes, say astronomers. The NASA article Earth rocks on the Moon claims the moon was perhaps three times closer some three to four billion years ago.

The moon is now swinging from apogee to perigee. For the next few nights, watch as the waxing gibbous moon crosses the midway point between these two extremes, hovering near its mean distance from Earth.

Bottom line: On February 4 and 5, 2012, the moon is in front of the constellation Gemini the Twins, near Gemini’s two brightest stars Castor and Pollux. What’s more, on these nights, the moon is near its mean distance from Earth: 384,400 kilometers (238,855 miles).

Tonight’s waxing gibbous moon resides inside the Winter Circle – an incredibly large star configuration made of six brilliant winter stars. Look for the Winter Circle to fill up much of the eastern half of sky at nightfall. By mid-evening, the Winter Circle will swing to your southern sky, and then it will drift into the western sky around midnight.

More on the Winter Circle: Brightest winter stars

By the way, if you see two star-like objects that shine more brilliantly than any of the Winter Circle stars, you are looking at the planets Venus and Jupiter. Venus, the brighter of these two dazzling worlds, pops out into the western sky at dusk and early evening. From northerly latitudes, Jupiter appears high in the southern sky as darkness falls, and as seen from the Southern Hemisphere, Jupiter is seen in the northwest at nightfall. Shortly after Venus sets in the west around mid-evening, look for the red planet Mars to rise in the east; and as Jupiter sits low in the west around midnight, that’s when the ringed planet Saturn comes up in the east.

February 2012 guide to the five visible planets

Setting and rising times for the planets in your sky

The Winter Circle – sometimes called the Winter Hexagon – is not one of the 88 recognized constellations. Rather, it’s an asterism – a pattern of stars that’s fairly easy to recognize. Our sky chart cannot adequately convey the Winter Circle’s humongous size! It dwarfs the constellation Orion the Hunter, which is a rather large constellation, occupying the southwestern part of the Winter Circle pattern.

Here’s how to locate the Winter Circle from mid-northern latitudes. At nightfall and early evening, look high overhead for the bright star Capella. This star marks the top (or more properly, the northern terminus) of the Winter Circle.

As Capella shines way overhead, the constellation Orion the Hunter is prowling in the southern sky. Draw a line downward through Orion’s Belt to find Sirius, the brightest star in the night sky. This star marks the bottom (the southern tip) of the Winter Circle.

We include this sky chart to help you connect the Winter Circle stars.

By the way, tonight’s waxing gibbous moon also nearly aligns with the June solstice point – where the sun resides in front of the backdrop stars on the first day of a Northern Hemisphere summer. So enjoy the Winter Circle. And contemplate the return of summer – months from now!

As seen from around the world, the waxing gibbous moon shines in front of the constellation Taurus the Bull tonight. Despite the moonlit glare, you may see the Bull’s two brightest stars: Aldebaran and Elnath. Aldebaran, the star depicting the Bull’s eye, is Taurus’ brightest star. Elnath, the constellation’s second brightest star, marks the tip of the Bull’s northern horn.

Aldebaran: Fiery eye of the Bull

Elnath: The northern horn of Taurus

Our sky chart is designed for mid-northern North American latitudes. The sky will look similar from mid-northern latitudes in Europe and Asia, except that the moon will be farther west in front of Taurus, closer to the star Aldebaran.

The rather faint star Zeta Tauri pinpoints the tip of the Bull’s southern horn, but the glary moon will make this star difficult if not impossible to see tonight. When the moon departs from the evening sky in a few more weeks, you should have no trouble seeing Zeta Tauri from a dark country sky. Starting around mid-February, in fact, should be ideal for viewing Taurus in all his starlit majesty.

The moon shines high in the south and Venus low in the west, with Jupiter in between

However, you won’t have any trouble seeing the planets Jupiter and Venus in the moonlit glare this evening. Look for these two dazzling worlds to line up with the moon, as shown on the sky chart.

On a dark night, deep-sky aficionados enjoy looking at the Crab Nebula (Messier 1) through a telescope. The Crab Nebula is found between the tips of the Bull’s horns, a tiny hop from the star Zeta Tauri.

Astronomers believe the Crab Nebula is the remnant of a star that exploded as a supernova in 1054 A.D. This supernova was so bright that it was seen with the unaided eye in the daytime for 23 days and at nighttime for 653 days. Tonight, on Thursday, February 2, look for the moon between Elnath and Aldebaran, then for the Crab Nebula with a telescope on a dark, moonless night!

Awesome 10-year-old discovers supernova

What is the safe distance between us and an exploding star?

Will you see the stars that represent the “stinger” in the constellation Scorpius the Scorpion in the cold dawn this month? From mid-northern latitudes, in the month of February, these stars served as a Pawnee version of Groundhog Day. You’ll need a clear, unobstructed view to the south to southeast to spot Scorpius’ stinger stars – Shaula and Lesath – flickering by the horizon.

Groundhog Day 2012: How accurate is Punxsutawney Phil?

Image credit: rkramer62

If you can’t spot these stars this week, try again later in February. For the Pawnee, who roamed the prairie of Kansas and Nebraska, the sky was a calendar, and the stars foretold the change of seasons. The Pawnee saw a snake in the stars forming the front part of Scorpius. But the stars of the stinger were, for the Pawnee, a pair of ducks. It is believed that the Pawnee called the stars on the Scorpion’s stinger the Swimming Duck stars. When the Swimming Ducks came into view in the southeast – prior to morning twilight in the month of February – the Pawnee recognized that it was time to begin planting ceremonies. In other words, spring was near. These stars are now coming into view at or shortly before dawn. In some respects, we can regard the search for the Swimming Duck stars as a Pawnee version of Groundhog Day.

The return of the Swimming Ducks to the morning sky signaled the first stirrings of the great plains from hibernation. Shaula and Lesath’s presence over the horizon was symbolic of waterfowl breaking through the ice.

As we approach the end of winter, Shaula and Lesath will appear higher each morning in the southeast before dawn. Their morning appearance tells us that the prairie is about to awaken to the rolling thunders of spring.

By the way, the stars at the end of the Scorpion’s tail are also known as the Cat’s Eyes. They’re easy to spot at the bottom of the recognizable star pattern that forms the constellation Scorpius.

So go ahead. Get up early on some morning this February. Look in the southeast for the Scorpion’s stinger stars near the horizon. If you’re lucky, you might behold them – a first glimmer of spring!

Everything you need to know about Groundhog Day 2012

Antares: Heart of the Scorpion

After sunset on January 31, 2012 take a look at the lineup of the Pleiades, the waxing moon and the planet Jupiter. From the Northern Hemisphere, they are high in the sky when the sun sets. From the Southern Hemisphere, they are low on the horizon. Another noticeable cluster, the Hyades, is near tonight’s moon, too. The bright planet Venus will also be visible low on the western horizon for part of this evening.

The Pleiades, moon and Jupiter should be easy to spot. The Pleiades – also called the Seven Sisters – is a dipper-shaped cluster – small, but very noticeable. Jupiter isn’t as bright as Venus, but it’s still very bright and noticeable not far from tonight’s moon. Jupiter is the third brightest object in tonight’s sky after the moon and Venus.

This lineup is a nice treat for mid-winter blues, if anybody has them, highlighting not one but two open star clusters visible to the naked eye.

First, we have the Pleiades, which is an open star cluster in the constellation Taurus. Six stars are visible with the unaided eye, forming a compact mini-dipper. A telescope reveals that this cluster contains several hundred stars. It is located 430 light-years away.

Then we have the Hyades open star cluster. This cluster is not in the lineup with Jupiter and the moon but close by. The Hyades is also in Taurus, and the brightest stars form the “V” in the face of the Bull. The bright red star Aldebaran is in the field of the Hyades but is 60 light-years away, while the Hyades’ stars are 150 light-years away.

Tonight’s grouping is found in the south to southwest sky at nightfall and early evening, with the Pleiades at the top left, and the moon and Jupiter to the lower right of the Pleiades.

Bottom line: On January 31, 2012, the moon is near several noticeable objects. First, there’s the tiny misty dipper-shaped star cluster called the Pleiades or Seven Sisters. Then there’s the planet Jupiter. Another noticeable cluster, the Hyades, is near tonight’s moon, too. The bright planet Venus will also be visible low on the western horizon for part of this evening. Lots to see! Check them out.