Hubble Scanning Moon for Base Sites

I know this is meant to be an astronomy blog, but I find this so cool I have to post it. The Hubble Space Telescope is being used to look for lunar base locations. I'll be packing my bags! Here's the story as told in New Scientist magazine.

Wanna See Something Beautiful?

Go out and look west tonight just after sunset and you'll see two extremely bright "stars" down near the horizon. These are really Jupiter, king of the gods, and his daughter Venus, goddess of love. Venus is the one on the lower right and Jupiter is up to the left.

Over the next two weeks they are going grow closer until they reach their closest on the nights of Wednesday, Aug. 31 and Thursday, Sept. 1. Keep watching as they part ways because on Tuesday, Sept. 6, they're going to be joined by a very slender sliver of a moon. Make sure to look for earthshine in the Moon's darkened limb that night.

Venus and Jupiter will be easiest to find about 30-45 minutes after sunset. If you have trouble finding planets, here's a Quicktime video of this conjunction from skyandtelescope.com that may help.

Full Green Corn Moon

The Moon is full today, Friday, Aug. 19. Because this is the month before harvest begins in many areas, this full moon is sometimes known as the Green Corn Moon or the Grain Moon. It's also the Full Sturgeon Moon, this being the season when that fish is most easily caught. (But don't ask me why--damn it, Jim, I'm an astronomer not a ichthyologist!) You'll find the names of each month's full moon here:

http://www.space.com/spacewatch/full_moon_names_2005.html

The Strolling Astronomer

The Strolling Astronomer
by Dave Adalian

During summer I take my walks after the Sun is down, when my family's gone to bed and the heat of the day has faded. I stroll among the stars, hoping for the thrill of a meteor and making sure those points of light are still fixed to their places.

My front door faces east, and as August fades the Great Square of Pegasus, part of the winged horse’s constellation, hovers above my neighbor’s rooftop. Later the Square will rise high into the night sky, trailing Pisces the Fish behind, but early on it sits on its eastern point, a huge diamond-shape of stars.

Right of Pegasus’ Square are the dim, indistinct zodiacal constellations of Aquarius the Water Bearer and Capricornus the Sea Goat. This seemingly empty ocean of sky has a single bright star, lonely Fomalhaut in Pisces Austrinus, the southern fish, hanging over the southeast horizon, bobbing above the houses as I lope along.

Beyond this barren portion of the night is Sagittarius the Archer with his famous Teapot asterism and to his right the long, barbed hook of Scorpius the Scorpion, home of the red supergiant star Antares. Despite the city lights, I can still sometimes see the Milky Way rising like steam from the Teapot’s spout to trail beside huge Ophiuchus, the snake-handler, whose healing power defied death itself until Zeus immortalized him in the sky.

Walking west, I see the orange star Arcturus shimmering in the heavy air marking Boötes the Plowman, and above it is a half-circle of stars, Corona Borealis, the Northern Crown. Higher still is brave Hercules, club at the ready.

As I march along, I catch glimpses of the Big Dipper in Ursa Major among the trees and housetops northwest, and due north is always faithful Polaris, the North Star, in the Little Dipper in Ursa Minor. When I finally turn back toward home again there is the W-shape of Cassiopeia the Queen standing on edge in the northeast, and below her the hero Perseus defending Andromeda, the Chained Lady, who lends her brightest star to Pegasus as the northernmost corner of his Square.

I arrive back at my doorstep and crane my neck to look straight overhead for the Summer Triangle: Altair in Aquila the Eagle, white Vega in Lyra the Lyre and Deneb marking the tail of Cygnus the Swan. Then I quietly steal inside, careful not to awake those who lie sleeping.

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This column appeared originally in the Visalia (Calif.) Times-Delta on Aug. 25, 2005.

And Still More Perseids

I woke up at a quarter past three and came back outside where I stayed until about a quarter after four, lying under a blanket on the diving board at the north end of the yard where the light is least. I spotted another 25 Perseids and three more meteors from other sources, including two that seemed to come from the direction of Aquarius, home to a minor shower or two this month. What a beautiful night of viewing, especially considering I was able to do it from my own backyard.

Perseids Watch

I did a short Perseid meteor watch from my backyard tonight starting at about 12:40 and going until just before 2 a.m. I saw 22 Perseids, some of them very bright and beautiful, and about five sporadic meteors. I'm going to get some sleep now, but I may come back for another look in about 90 minutes.

Astronomy TV Online

Here are a couple of astronomy-oriented television programs available via the web:

First, here's Jack Horkheimer's Star Gazer, a series of one- and five-minute programs on the week's astronomical highlights. And, second, the venerable The Sky at Night hosted by Sir Patrick Moore.

Getting to the Purcell Observatory

Getting to the Arthur L. Purcell Observatory is very simple in broad daylight, but can be a bit tricky in the dark.

Take Highway 99 south past Tulare to the Avenue 184 exit. Turn left onto Avenue 184 and drive west approximately 2.1 miles. To do this you'll have to go through the intersection of 184 and Road 96; the observatory is about half a mile past the intersection on the right-hand (north) side of the road, so keep an eye on your odometer.

We have a sign for the observatory at end of the driveway, but it sits slightly off the road and is not lighted. The driveway leads to our parking lot, and the observing is done in our courtyard just beyond.

If you're not comfortable walking in darkness, a flashlight with a red filter will help, but please do not use unshielded lighting once you have left the parking lot.

This interactive Google map can provide driving directions from any location in Tulare County.

Welcome to Starry Nights!

Welcome!

This is the new online home of my astronomy column, Starry Nights, published monthly in the Visalia (Calif.) Times-Delta. Besides posting my columns both old and new, I'll be including interesting astronomy-related news and links, as well as announcements of the Tulare Astronomical Association's monthly star parties.

Comet Dust Drives Summer Shower

Comet Dust Drives Summer Shower
by Dave Adalian

(July 28, 2005) Anyone who attempted to observe Comet Tempel 1 earlier this month when NASA’s Deep Impact probe slammed it with an 814-pound copper bullet moving at 6.3 miles a second knows first-hand comets are an unpredictable lot.

Hopes were high this visitor from the outer reaches of the Solar System would brighten from an almost undetectable smudge in small telescopes to a naked-eye delight. The mission succeeded, but the brightening didn’t happen.

Fortunately, next month holds good promise of a sort for would-be comet observers.

August, as seasoned meteor observers know, is time for the year’s most reliable meteor sky show. The Perseids began lighting the night sky early this week and continue until late August with the peak expected to produce between 40-80 meteors an hour on the night of Aug. 11-12 and perhaps again on Aug. 12-13. Meteors from other minor showers will add 15-20 an hour.

Perseus, the constellation from which the Perseids stream, rises in the northeast around 10 o’clock. The best meteor viewing is after moonset--around 11 the first night and nearer midnight the next--until dawn. The darker sky you find yourself under, the better the viewing will be.

What does this have to do with comets? The Perseids are tiny pieces of Comet Swift-Tuttle.

Meteors aren’t really stars falling from the sky. Instead, they are bits that have broken off of other bodies--usually ice and dust the consistency of ash or more rarely solid rock--colliding with Earth’s atmosphere at several thousand miles an hour, ionizing the air and producing that magical glow.

Comet Swift-Tuttle is a periodic comet, returning again and again to swing around the Sun before heading off to the dark and frozen outskirts of our star system on a 135-year circuit. While Swift-Tuttle was first discovered in 1862, the shower it produces is known throughout history. During the 11th century, astronomers in China recorded an intense display, and Perseids are sometimes called St. Lawrence’s Tears to honor his martyrdom in coincidence with the shower of 258.

Swift-Tuttle returned most recently in 1992, freshening its trail of debris significantly as the Sun’s gravity drew the comet in, warming its surface and causing it to shed potential meteors. Therein lies this comet’s uncertainty. This year Earth enters the 1992 debris stream for the first time, and the usual rates of 40-80 meteors an hour on nights near the shower’s peak could be far higher than normal.

Or maybe not... We’ll just have to see.

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This column originally appeared in the Visalia (Calif.) Times-Delta on July 28, 2005.

When Worlds Collide

When Worlds Collide
by Dave Adalian

The cusp of June into July is going to be a planet-hunter’s delight this year.

Eighty-eight-thousand-mile-wide Jupiter continues to reign over the southern sky, shining high after sunset. Ruddy Mars, as it moves toward another close pass by Earth in mid-November, is coming up in the east for night owls at around 1:30 a.m., just as Jupiter is retiring on the opposite horizon.

The three outer planets--Uranus, Neptune and Pluto--are all available to those with telescopes during various times through the shortened dark hours of early summer. From an unpolluted sky, those who know exactly where to look, perhaps by using an online guide such as www.skymaps.com, can see blue-green Uranus with the naked eye.

The real show, however, is in the west just after the Sun reaches the horizon.

Those who followed the progress of Saturn this year as it hovered in the constellation Gemini know it is coming to the end of its 2005 appearance. As June closes, Saturn is only visible for a short time before it follows the Sun and slips below the western horizon.

Already Saturn is almost lost in the afterglow of twilight and hard to see until at least 30 minutes after the Sun is gone. Look tonight around 9 o’clock to see that Saturn has a bright companion, Venus, sitting very close by and outshining it.

In fact, brilliant Venus sits at the center of a trio of planets, with Saturn to her left and speedy Mercury on the right. Together the three span only three degrees, just six full-Moon widths.

Friday the trio is even tighter, sharing just two degrees of sky, and the group will be its tightest on Saturday when Saturn, Venus and Mercury are just one and a half degrees apart with the ringed planet below the two innermost planets of our star system.

While they sit close compare the pink of Mercury, blue-white Venus and yellow Saturn. Notice too how the trio sits undisturbed in the sky while around them stars shimmer in the gloaming.

Keen-eyed observers noticed Mercury rising to meet Venus while the planetary trio gathered. Mercury moves closer still the next two nights as Saturn retreats until on Monday the two are less than one tenth of a degree apart, so close they may appear to the eye as a single point of light. The merger is a once-in-a-lifetime event, not happening again until 2070.

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This column appeared originally in the Visalia (Calif.) Times-Delta on June 23, 2005.

Hopping through the Sky

Hopping through the Sky
by Dave Adalian

Anyone who’s ever looked up at night has noticed a problem facing astronomers: there are a lot of stars up there, and it’s easy to get lost in space.

That’s one of the reasons we have constellations, to help us fix in our minds the location of the wonders of the night. Still, knowing where to find a constellation only gives us the general location of whole groups of stars, some of them very large. How does anyone find anything among all those points of light?

They hop to it.

Star-hopping is an age-old and easy technique. Start by finding a bright star or well known constellation and connect the dots to find the target.

The best known star-hop is the Arc to Arcturus. It starts with one of the better known constellations in the sky, Ursa Major, the Big Bear.

The most recognized star shape in the sky, the Big Dipper, lies in the Ursa Major. Find it by looking due north just after sundown. As spring wraps up, the Big Dipper pours its contents onto the North Star and its tail points up and toward the east.

Follow the arc along the three bright handle stars about the same distance as the length of the Dipper to come to the first stop, the orange giant star Arcturus.

Arcturus is the brightest star in cone-shaped Boötes (boo-OH-tes), the Herdsman, and the fourth brightest seen from Earth. It’s 20 times larger than the Sun and shines 115 times brighter from 37 light years away. Arcturus is so bright in the infrared we can measure its heat here on Earth--the same as a candle flame five miles away.

Arcturus is one of the fastest stars, traveling at 90 miles a second toward Virgo, the second stop on this star-hop. If you “speed” along the arc past Arcturus, you’ll soon come to first-magnitude Spica, Virgo’s brightest star. Like Arcturus, Spica is brighter than the Sun, 13,400 times so, and masses 11 times more, but it sits 260 light years away.

Continue the arc again to reach our final stop, Corvus the Crow, an irregular box of four stars that is normally not a big attraction. Currently, however, it’s pointing its beak towards Jupiter, which sits directly above the Crow.

Astronomers have an alliterative phrase to remember this popular hop: “Arc to Arcturus, speed on to Spica and continue on to Corvus.”

Enjoy the ride!

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This column appeared originally in the Visalia (Calif.) Times-Delta on May 26, 2005.

Moon to Hide Supergiant

Moon to Hide Supergiant
by Dave Adalian

A fat full Moon is usually a problem for astronomers, its bright, white light washing fainter objects from the sky. Other times, it’s the star of the show, as it will be the night of May 23-24 when the Moon occults the red supergiant star Antares.

Occultation is a body blocking the view of another more distant body, and a few minutes before midnight on May 23 the Moon will do just that to the ruddy star at the heart of Scorpius. The show, however, starts at sunset.

In Arabic, Antares is called Kalb al Akrab, heart of the scorpion, and staying true to this metaphor, early Muslims named two bright nearby stars Al Niyat, the arteries. The brighter of the two artery stars, Al Niyat (Sigma), will be behind the Moon when it rises. Stargazers with access to a very clear horizon will see this third-magnitude star reemerge from behind the lunar disk at about 8:48.

About then Antares will become visible above the horizon, one and a half degrees or so below the Moon. As the Moon travels west across the sky, it moves east through against the starry background at about half a degree or one full-Moon width an hour, edging ever closer to Antares as midnight approaches.

The Moon appears much brighter and larger than Antares, but this is a mere deception of distance. The Moon is just a quarter million or so miles away and is roughly 2,000 miles wide at its equator. Antares, on the other hand, lies 600 light years away, is 12,000 times brighter than the Sun and measures 745 million miles across. Keep this in mind when the Moon makes supergiant Antares disappear from the sky at four minutes from midnight.

Another thing to keep in mind is Antares advanced age. While it is younger than Sol, our star, it is much larger and brighter, meaning a far shorter lifespan. When the end comes for Antares, it will be with a bang--because of its size, Antares will end life as a supernova.

That explosion could come at anytime, a million years from now or while the Moon is hiding it from view. Likely, Antares will emerge from behind the Moon at 1:12 a.m. no different than when it disappeared. Or, it may reappear as the aftermath of a titanic stellar explosion, outshining all the other stars in our galaxy combined.

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This column appeared originally in the Visalia (Calif.) Times-Delta in April 2005.

Return of the King

Return of the King
by Dave Adalian

What’s bigger than a bread box, smaller than the Sun and the brightest thing in the night sky after the Moon these days? It’s 88,000-mile-wide Jupiter!

Those with eyes for the skies may have recognized the bright object dominating the east after sunset the last few weeks as the King of Planets. A fixture in the winter sky for the past few years, Jupiter is making the transition to spring skies as it moves to opposition--when it appears opposite the Sun and is up all night--on Sunday, April 3.

Not to insult the King, but Jupiter really is an old gas bag, and a big one to boot. Jupiter is the largest thing in the Solar System after the Sun, and while it’s only about six times wider than Earth, it would take more than the volume of 1,000 Earths to fill Jupiter’s interior.

Jupiter is so large that it contains more mass than all of the other planets combined, 1.9x10^27 kilograms worth--that’s a 19 followed by 26 zeroes! Astronomers who think they’re cleaver like to say the Solar System is made up of the Sun, Jupiter and assorted rubble.

The Jupiter System itself is fairly rocky, too. When Galileo first viewed Jupiter through a telescope in 1610 he saw just the four bright moons Io, Europa, Ganymede and Callisto. These days, Jupiter’s official NASA moon count is up to 63, with the smallest measuring just three miles across.

Moons aren’t the only thing going around Jupiter. Like Saturn, this gas giant planet also has a set of rings. Jupiter’s rings are much less complex and dimmer, so much so they weren’t discovered until Voyager I visited in 1979.

Like the Sun, the Jupiter is mostly hydrogen, and because of the gravitational pressure of its mass, inside temperatures reach more than 10,000 degrees Fahrenheit. That pressure has caused the formation of a core of metallic hydrogen 6,000 miles below the surface of Jupiter’s atmosphere. Some scientists believe the planet also has a rocky core 10 times the mass of Earth. Others disagree, saying it’s hydrogen all the way through.

In the telescope, dark, cloudy bands reveal themselves on Jupiter’s disk. The four bright Galilean moons are obvious as they dance along night to night, and careful observation reveals the Great Red Spot, a storm three times larger than Earth that has raged since before its discovery in 1664.

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This column appeared originally in the Visalia (Calif.) Times-Delta in April 2005.

Vernal Equinox on the Horizon

Vernal Equinox on the Horizon
by Dave Adalian

Despite winter’s best efforts, spring is finally showing. Buds are turning to blossoms and temperatures are rising. The Sun is making the occasional appearance between rainstorms and soon it will let us know the season has changed.

Imagine the Sun, stars and planets as points of light on the inside of an enormous sphere surrounding Earth. Next, project a circle from Earth’s equator onto the sphere, forming a celestial equator dividing the sky into northern and southern halves. Then imagine another circle on the sphere, this one marking the Sun’s apparent path during the course of a year.

The two circles don’t match, and it’s that misalignment that causes Earth’s seasons. During winter months, the Sun sits south of the celestial equator so the northern hemisphere gets less light and temperatures drop. In the summer, the Sun appears to be north of that line and daylight hours are longer and hotter.

Twice a year, once in March and again six months later in September, the line marking the Sun’s progress and the celestial equator intersect. These events are known as equinoxes, Latin for equal night, and they mark the changes of summer to autumn and winter to spring.

This year’s vernal--or spring--equinox will happen at 4:34 a.m. PST on Sunday, March 20, when the Sun crosses the celestial equator and moves into the northern half of the sky. At that moment spring begins, and for a few days on either side of the event nighttime and daytime will be the same length.

Not coincidentally, the Sun rises exactly east on a few days surrounding the equinox and sets directly west. During the course of summer, the point on the horizon where the Sun rises and sets will appear to move north until summer solstice in June, when it again decsends toward fall.

The vernal equinox has been an important event for humans since the dawn of civilization. Ancient Egyptians paid homage to it by building the Sphinx to face sunrise that day, and closer to home the Mexican Pyramid of Kulkulkan, honoring the serpent god Quetzalcoatl, was designed so the shadow of the god appeared to slither down the steps on the equinox.

But, forget the egg balancing. Raw eggs do not balance on their ends more easily on the equinox. A Chinese New Year’s ritual performed about six weeks before the vernal equinox is the source of the myth.

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This column appeared originally in the Visalia (Calif.) Times-Delta on March 3, 2005.

Time to Look at Mars Again

Time to Look at Mars Again
by Dave Adalian

Planet Mars grabbed big headlines in summer of 2003, making its closest approach to Earth in 60,000 years while millions turned out worldwide for the spectacular show.

Lately, the Red Planet has been sitting dim and far away on the other side of the Sun, but during the next 10 months that will change as Earth cozies up for another close pass. With nearly a year before Mars again becomes one of the brightest objects in the night sky, now is the time to start watching.

Think of Earth and Mars as cars on a race track. Mars sits farther out, moving slowly, while Earth roars along on an inside track. Even though Mars isn’t the speedster Earth is, it still takes us some 28 months to lap it, which is why we’re only starting to get good views of it again now as Earth rounds her home star.

Getting up early is required for finding Mars. The God of War is currently rising about 4 o’clock in the morning, but doesn’t clear the treetops until 30 minutes or so later. To sight it, look to the southeast near the horizon for its pink light.

Don’t confuse Mars with much brighter Antares, the brightest star in the constellation Scorpius that is also not far above the horizon in the southeast, but up and to the right of Mars. This red star is actually named for its resemblance to the Red Planet. Antares means rival of Aries, the Greek name for Mars.

Mars now sits just west of Sagittarius and will have moved to the east side of the Celestial Archer by month’s end. But, because it moves in the same direction around the Sun as Earth, there isn’t much change in the time it rises until the they’re far closer together. By April, Mars is up around 3 a.m., rising in Capricornus, and in May it’s up by 2 o’clock in Aquarius.

It spends the summer cruising through Pisces, picking up an hour each month and brightening along the way. Through September, Mars rises just after 9 p.m., almost due east, in Aries, where it will stay until it reaches its brightest and closest by mid-November. Then, it rises at sunset to shine overhead by midnight.

Mars won’t be as spectacular as summer 2003, but will certainly be well worth seeing, especially for those who weren’t watching the last go-round.

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This column appeared originally in the Visalia (Calif.) Times-Delta on Feb. 3, 2005.

Winter Stars Are Brighter

Winter Stars Are Brighter
by Dave Adalian

Nights in winter seem starrier partially due to drier air overhead, but mostly because there are just more bright stars in the winter sky.

Winter begins with the Summer Triangle of Vega, Deneb and Altair lingering in the west after sundown. These jewels set quickly, and on the opposite side of the sky the Winter Hexagon’s easternmost members emerge.

By 7 o’clock, Sirius is high enough for viewing east of Orion’s belt. The Dog Star shines from 8.6 light years away in Canis Major, but because it is 20 times brighter than our sun remains the brightest star that can be seen from Earth at magnitude -1.4.

Sitting at due east and rising just before Sirius is a magnitude-0.0 star 11.4 light years distant. Because it rises just ahead of Sirius it’s known as Procyon, which means before the dog. A double star, its companion is a tiny, invisible white dwarf.

To the northwest, the third corner of the Hexagon is occupied by Castor and Pollux, the twins of Gemini. Between the twins and Procyon lies bright yellow Saturn, which will be much in the news later this month when the Huygens probe lands on its moon Titan.

Pollux, a magnitude-1.1 star 33.7 light years distant, glows orange. Farther, dimmer Castor--magnitude 1.6 at 51.5 light years--appears white to the eye. Through a telescope Castor becomes three stars, and though not visible each of these is a double for a total of six suns looking like one to the naked eye.

Above and right of the Twins is Capella, the fourth corner of the Hexagon and the sky’s sixth brightest star at magnitude 0.1. It shines from 41 light years away in Auriga the Charioteer.

Lower and farther right is Aldebaran, the red eye of Taurus the Bull, occupying the fifth spot at 60 light years away and magnitude 0.9.

Completing the Hexagon is Rigel, brightest of stars in Orion and just right of his belt. Even though it is some 1,400 light years away, Rigel still shines at magnitude 0.5, making it seventh brightest as seen from Earth.

While Rigel officially ends the lap around the Winter Hexagon, many find it natural to make a sharp left to finish up at magnitude 0.5 Betelgeuse, which also sits some 1,400 light years distant. This red giant is nearing the end of its life, making it a prime candidate to go supernova.

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This column originally appeared in the Visalia (Calif.) Times-Delta on Jan. 6, 2005.

Something's Missing from the Night Sky

Something's Missing from the Night Sky
by Dave Adalian

Something is missing from the night sky.

Looking north just after dark in December, stargazers will find the familiar Big Dipper of Ursa Major gone.

It hasn’t vanished. The well-known asterism is now at its lowest and most northerly for the year, so that it hangs partially hidden behind the horizon and the trees, buildings and mountains that obscure it. This is the season when whatever celestial liqueur it is that passes between these stellar vessels flows from the Little Dipper of Ursa Minor into its greater counterpart.

It may seem strange to think of the Dipper as anything other than itself, but these stars have almost as many names as there have been cultures of men gazing up at them.

It could be the low, late-autumn sweep--which sends the Dipper’s stars cutting into the earth--that prompts Britons to call the group of seven bright stars the Plow. Across the English Channel, the French call it the Saucepan.

Of course Greeks and Romans saw the Great Bear that gave us the name Ursa Major, but several other cultures around the ancient world did, too. Micmacs of North America see the four stars of the Dipper’s bowl as the feet of a bear that slowly circled the North Star. Iroquois imagine a group of hunters following a bear.

The Chumash of the Central Coast tell a story of seven boys who ran away from homes where they weren’t wanted and turned into geese, and Pawnee legend describes a sick man carried on a stretcher.

Many cultures have seen the Big Dipper as a wagon. Norse myth puts Thor at the reins, while Germanic legend says it belongs to his father Odin. Coming full circle, the Chinese version includes a horse-drawn wagon for the celestial emperor on the back of a bear.

While the Big Dipper is low after sunset, it rises quickly to stand on its handle by 10 o’clock. This happens earlier each night as we move into winter.

The middle five stars of the Dipper comprise an open cluster, all of them moving together through the galaxy. This cluster, at 75 light years to its nearest sun, may be the closest to Earth. Or not. Sol moves in nearly the same way, leading some astronomers to conclude we may be part of the cluster ourselves, our star forming from the same dust cloud as those of the Big Dipper.

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This column appeared originally in the Visalia (Calif.) Times-Delta in December 2004.

A Season of Long Nights

A Season of Long Nights
by Dave Adalian

As autumn ripens after the October rains and fog, a season of long nights begins. Day turns to evening during the dinner hour and skies darken early for digestive strolls spent wandering with the stars.

With no moon this week, nights will be dark and starry. Walkers will notice the Summer Triangle of Vega, Altair and Deneb still riding high in the west after sundown, while at the same time, the Great Square of Pegasus shines in the east. Already well up in the sky, by the end of the month the Square will be overhead just after dusk, a telltale of the coming of winter.

Alpheratz, the star marking the northeast corner of the Great Square, is actually the brightest in the constellation Andromeda. This willowy arrangement of stars represents a celestial princess awaiting rescue by Perseus, the Greek hero who slew Medusa. Not far to the northeast of Alpheratz, look closely to find the faint wisp of that is the Great Andromeda Galaxy, one of the Milky Way’s closest neighbors at only 2.9 million light years distant. It is the farthest object that can be seen by the unaided eye.

The constellation Perseus itself lies farther to the northeast of Andromeda, a riot of stars sitting just below the W of Andromeda’s mother Cassiopeia. Below it and to the right are the wonders of Taurus the Bull discussed here last month--the Pleiades, the Hyades and the bright red giant star Aldebaran.

The Moon returns to the early evening sky in mid-month, appearing briefly as a thin crescent in the southwest the nights of Nov. 15 and 16, when it will sit in Sagittarius.

Each month the Moon traipses through the Zodiac, rising earlier night to night and making the stars seem faint by comparison as it brightens. By Nov. 17 Luna is amid the dim stars of Capricornus, the Sea Goat. Two nights later it’s well into Aquarius, the Water Barer, and on Nov. 22 it swims with the fishes of Pisces.

By Nov. 24, the almost full Moon sits in Aries the Ram, a group of dim stars remembered because of its association with astrology. Aries’ three brightest stars, representing the ram’s horns of plenty, sit directly above the Moon this night before Thanksgiving.

The Moon is in Taurus when full two nights later, then finishes the month with the twins of Gemini, rising just after dark.

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This column appeared originally in the Visalia (Calif.) Times-Delta in November 2004.

Taurus Marks Return of Fall

Taurus Marks Return of Fall
by Dave Adalian

Astronomers mark the Valley’s slow decent into autumn not by the colors of the leaves and a drop in the mercury alone. They watch too for the return of Taurus the Bull to the night sky.

This compact constellation of the Zodiac rises in the east just after sunset during October, bringing a dazzling string of astronomical delights as it stampedes over the horizon.

First to rise is the Pleiades, those famous Seven Sisters the Japanese call Subaru. This compact group of stars--an open cluster some 380 light years distant--dazzles the eye with hot, white stars that shine and twinkle like diamonds through the Valley haze of walnut dust and cotton defoliant.

From the city the best one can hope to see are the six brightest stars of the Pleiades in a shape some people mistake for the much larger Little Dipper of Ursa Minor in the north. A dark night in the countryside will push that number to about nine, while getting above the smog will produce as many as a dozen for the naked eye when the Moon is new.

In total, the cluster contains some 500 stars, many of which can be seen in a backyard telescope.

Below the Sisters and rising about an hour later is Taurus’s less famous open cluster, the Hyades. This V-shaped cluster is perhaps the closest one to Earth at 150 light years distant. The Hyades, another group of sisters from Greek mythology who died from grief for their brother Hyas, represent the face of Taurus.

At the end of the eastern arm of the V is the bright red star Aldebaran, which marks the angry, bloodshot eye of the charging bull. While Aldebaran appears to be part of the Hyades cluster it is actually less than half the distance at just 60 light years.

Telescopes reveal another treasure of Taurus lost to those with unaided eyes. Rising after the Hyades comes the Crab Nebula, the remains of an exploded star that dazzled during the nights of 1054 A.D. The event was reported by Chinese astronomers, and natives of the American Southwest depicted it on canyon walls.

Taurus holds one last charm for those who scan the autumn night--a minor meteor shower. The Northern Taurids begin the second week of October and last through the start of December, displaying a handful of bright shooting stars every hour from between the horns of the bull.

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This column originally appeared in the Visalia (Calif.) Times-Delta in October 2004.