Happy Holidays from the Southworth Planetarium!

So, after reading “A Pleasant Evening Spoiled,” a subscriber wrote and asked,
“Have you ever thought about taking some time off?”

Well.

It was my plan to take the rest of the week off even before this subtle hint. Generally, we only take the last half of August off. However, it is the holidays and people have much more important considerations right now than reading the DA, although one can’t imagine what those might be.

We shall return on Monday, December 28, 2009.

May you and yours have a beautiful Christmas.
If you don’t celebrate Christmas, have a beautiful week!
If you don’t believe in beautiful weeks, well, have an average looking week.

One point before I depart:

An eagle-eyed subscriber RV from NH pointed out an error in the 50 brightest stars DA. I need to correct it, because it was a dorky error even by my standards.

The Big Dipper has seven stars (I got that part right)
However, the outer bowl stars’ names are Dubhe and Merak (I got that part right, too)
Where I stumbled was in transposing their names. Merak is the star at the bottom outer corner and Dubhe is the star in the upper outer corner (the star that is closer to Polaris than Merak.)
I assert that I did know that, but I was so intoxicated with bliss over my brother having a birthday (and me not having one) that I made this slip-up.

My apologies!

Also, in reference to another subscriber’s e-mail pertaining to the last DA: Yes, “Astronomy Monopoly” is a real game. We thought about selling it in our gift shop. However, like the party game, “Guess what I secretly think is wrong about you, dear,” the game “Astronomy Monopoly” is nothing but trouble.

Cheers from the Cosmic Underground
Edward

DA December 22, 2009 A Pleasant Evening Spoiled

From the USM Southworth Planetarium
“A trickle of fra la in a basin of humbug”

THE DAILY ASTRONOMER
December 22, 2009
A Pleasant Evening Spoiled

As it is holiday week, I decided to take the day off. So, instead of sending an article, I decided merely to give you a ring side seat at our family holiday festivities. Doing so saves me a lot of work-I don’t feel like writing, anyway- and since indolence is the truly joyous part of the holidays, I’m all for being utterly and seasonally irresponsible.

Christmas Eve

Yes,the sky was perfectly clear,the closest cloud being somewhere off the Nantucket shore. Out beyond the frosted windows the deeps of night beckoned. Just above the ice crystal white of the window’s corner arose Orion’s belt; poised above the porch, the firefly tangle of the Pleiades. The gibbous moon was cast in subtle reflection upon the snow field’s glistening ices as Sirius sparkled through the intertwined branches of pines and barren oak. It was this summons to explore the murmuring wonder world beyond the door that we indifferent lumps cheerfully ignored from the sanctity of our unnatural living room.

That was the ideal place for the holiday observance: the sweet warmth of a living room lit by soft icicle lights, a blinking Christmas Tree, and mantelpiece candles above the dancing ember glow of the blazing hearth fire.
On the sofa,Aunt Moira thumbed through a Popular Mechanics while Uncle Patrick deftly crocheted that star spangled, Independence Day quilt that he figured couldn’t wait another day. Cousin Sean bent over his scattered papers,intent upon his purpose. He was one of those poor enslaved souls unable to wrest himself away from work even around the holidays. Cousin Sheila’s laugh emanated from the kitchen, where she shared private moments with her indecently handsome rugby player boyfriend. She was keeping him out of the living room, in case Aunt Moira wanted an arm wrestling re-match.
Liam was also absent. We had no idea where he could have gone when he scampered out of the living room ten minutes before. It was only when we heard frantic footfalls down the corridor that we figured out he must have been somewhere around the hall. He clamored hastily into the living room,holding a box under his arm.

LIAM: I’ve got it! ha ha Now, by God, it’s a party!

AUNT MOIRA: (resignedly) What do you have, Liam?

LIAM: (slapping the box cheerfully) A board game.

(Wonderful! An evening of fun and family togetherness enhanced by fierce competition.)

UNCLE PATRICK: (annoyed) A board what?

LIAM:Game. You know, a thing that well groomed families sit around in those nifty pictures they put on the instruction manual. I figured it’s something we could, you know, do together, you know, as a, well,as a family.

UNCLE PATRICK: (confused) Why would we want to do that?

LIAM: Because it’s Christmas Eve! A time, you know, when families should be enjoying each other.

UNCLE PATRICK: What do you think we’ve been doing?

LIAM: We’ve been ignoring each other completely!

UNCLE PATRICK: Best way to enjoy family.

LIAM:Oh,that’s not the holiday spirit at all! Let’s all play this game! It took me a damn long time to find it. You can darn that scarf later.

UNCLE PATRICK: (angrily) It’s a quilt!

LIAM: Looks like a scarf

UNCLE PATRICK: I just started working on it.

LIAM: Well,you shouldn’t call it a quilt until it actually starts looking like one. Call it a proto-quilt or something. Besides, you can’t work on it if you don’t have your table (pulls it away from Uncle Patrick)

UNCLE PATRICK: Hey!

LIAM: Well, we can’t play on the floor. So, who’s in?

During the fifteen seconds that followed Liam’s question, the sounds of loons about a half mile down the river were quite loud, as was the traffic on a distant highway.

LIAM: Anyone?

And the mouse in that basement then sounded like it had just happened upon a tasty morsel,which it consumed with audible relish.

LIAM: Please?

DA: Ok, I’m in.

LIAM: Great. Anyone else?

AUNT MOIRA: (sighing) I suppose if it is this important to you, Liam.

LIAM: Wonderful!

AUNT MOIRA: Your Uncle Patrick will join us, won’t you, Patrick?

UNCLE PATRICK: (in a sneering whisper) It’s a quilt….

AUNT MOIRA: And, so will Sean. Sean?

COUSIN SEAN: (jerking his head up) I’m sorry, what?!

AUNT MOIRA: Put away whatever it is you’re working on. We’re going to have some family time.

COUSIN SEAN: We’re having a bail collection meeting on Christmas Eve?

AUNT MOIRA: (thin-lipped) We are going to play a game that Liam has picked out.

COUSIN SEAN: Um, ok. Which one?

Liam showed him the box.

LIAM:You know this one. Remember? You and I played it last year and made all those supplemental rules to make it more interesting.

COUSIN SEAN: Oh, yeah! Sure, I’ll play.

LIAM: Do you think Sheila and Atlas Major in the kitchen would like to play?

AUNT MOIRA: Let them be. They sound like they’re having fun.

UNCLE PATRICK: (under his breath) Somebody has to.

AUNT MOIRA: (slaps his arm) Shhh! I’ll get some chairs

UNCLE PATRICK: (moving from the couch to the table) So, what game is this, anyway?

LIAM: (proudly) Monopoly.

UNCLE PATRICK:Oh, ho, boys! This might be fun after all. You might want to re-think this, guys. (rolls up his sleeves). I have to tell you, I’m a bit of a Monopoly shark, you know.

Uncle Patrick then stopped short as Liam opened the game onto the table.

UNCLE PATRICK: What the devil is that?!

AUNT MOIRA: (scolding) Pat, it’s Christmas!

UNCLE PATRICK: Sorry. What the Hell is that?!

LIAM: What does it look like? It’s Monopoly

UNCLE PATRICK: That ain’t any Monopoly board I’ve ever seen.

LIAM: Of course not. It’s ASTRONOMY Monopoly

DA: (turning tail and moving toward the door) Good night!

LIAM: Hey, you said you’d play!

DA: Sorry. Sudden leg cramp. Can’t possibly make it around the board.

LIAM: Oh, come on!

AUNT MOIRA: (calling after DA) Please… It’s Christmas.

DA: (waving behind his head as he whips out of sight): Shalom.

LIAM: Oh, fine, be that way, you coward. See if I care! We’ll have a great time without you.

It was the work of a moment to seat all four of them around the table and distribute the money, assign the pieces and organize the cards. Uncle Patrick was too astonished by the sight of the celestial images to pay much attention to the 13 pairs of dice within the box.

LIAM:(excitedly rubbing a die in his hands) Now, we have to determine who goes first. Uncle Patrick, pick a number between one and ten.

UNCLE PATRICK (with brow wrinkled in confusion): Um, three?

LIAM: Wrong! I go first.

UNCLE PATRICK (glaring at Aunt Moira): What the…

AUNT MOIRA: Let’s just play, Pat. Go ahead, Liam.

Liam rolled two die and landed on Mars.

LIAM: Nah! Be hard to maintain hotels without any oxygen or water. Ah, ha ha…I made a funny.

UNCLE PATRICK: (already seething)

They went through Aunt Moira’s turn and then Sean’s before Patrick took the dice. He rolled and landed on Saturn.

UNCLE PATRICK: (handing Sean the money) I’ll buy it.

COUSIN SEAN:Ok, I can get that card. Just a moment. I arranged them according to which space object was my favorite, followed by my second favorite,then third, and so on, like that. Probably should have stacked them according to set, but that seemed a bit, well,dull. Problem is I can’t remember how much I like Saturn.

AUNT MOIRA: (standing up and moving toward the kitchen) Why don’t I go get everyone a glass of water…

COUSIN SEAN: Oh, here it is. Ok, now, the question.

UNCLE PATRICK: Question?

COUSIN SEAN: Yeah,well,in this game, you have to answer a question about the property you’re buying before you can buy it. It really makes sense, you know, because, well in real life, if you’re buying a home, you should know a lot about it.How many doors it has…how it’s upholstered….its highway mileage.

AUNT MOIRA:(returning to the living room with the water) Here you go,dear. I used the plastic cup already ruined by teeth marks.

COUSIN SEAN:(rifling through a set of hand written index cards) Ok, here it is: “Saturn’s largest moon is blank.” Well, it doesn’t actually say,”blank,” it is just a blank line,you see. You have to fill in the blank.

UNCLE PATRICK: I don’t want Saturn anymore.

COUSIN SEAN: (shaking head): Sorry. No refunds for planets. The return shipping charge is murder. ha ha

LIAM: (elbowing Uncle Patrick playfully) Now he made a funny.

AUNT MOIRA: Drink that water slowly dear.

LIAM: I don’t think Uncle Patrick cares too much for astronomy, Sean. Better ask him another type of question.

COUSIN SEAN: Like what?

LIAM: Anything else. Just make it for a simpleton.

UNCLE PATRICK: (red faced)

LIAM: (hurriedly) I mean, make it simple!

COUSIN SEAN: Um, ok….uh, let’s see. Ok, name a famous Italian Renaissance artist.

UNCLE PATRICK: (through set teeth) Vince Lombardi

LIAM: Ok, show off…what century did he live in?

AUNT MOIRA: Can we do this without questions? I think it would be more fun for everyone.

COUSIN SEAN: (looking a bit wounded, as he puts the index cards on the floor.) Ok.

So ,for the next fifteen minutes, the players took their turns in silence:pieces advanced around the board; properties were sold; fees paid; jail time avoided and all was going swimmingly until…

LIAM: WOW!

COUSIN SEAN: Wow is right! Good for you, Liam.

LIAM: And people tell me I’m not talented.

COUSIN SEAN: They’ll eat their words now, by gum.

LIAM: You bet your bottom peso they will, hombre.

COUSIN SEAN: Please stick to English. Using Latin makes you sound pedantic.

LIAM: Whatever. Just give me the dice

UNCLE PATRICK(whose eyes were suddenly fatigued from having darted back and forth repeatedly between Sean and Liam): What’s all the fuss about? You just landed on one of the comet properties.

COUSIN SEAN:(placing his hand on Uncle Patrick’s arm) I know it looks that way to the untrained eye, but Liam just landed on a prime number space with a prime number roll during a prime number turn. Consequently, he is permitted to activate the hyperspace function. Hence, (he hands 24 dice over to Liam) the necessity of the extra dice. You might want to backup:the scattering effect of all those tossed die ..or dice…could prove a bit dangerous.

Liam rolled all 26 dice and came up with 81. So,he moved around the 40-space board twice before advancing one more space, which put him exactly one space ahead of where he was before: on the same space with Uncle Patrick.

COUSIN SEAN: (gravely) Oh

LIAM: (even more gravely) Oh

COUSIN SEAN: Not good.

LIAM: Beyond not good.

UNCLE PATRICK (nursing his eyes) Now what?!

COUSIN SEAN: You two occupy the same space. You haven’t done that before, but I was dreading the eventuality.

UNCLE PATRICK: (wincing) Why?

LIAM:You see,uncle,we’re enemies. WELL, NO! Not, you and I, of course ,but our pieces are. If you had paid attention to our rule book appendices, paying particular attention, of course, to Appendix 1,sub-section B,you would have known that my piece’s ancestors were once enslaved by your piece’s ancestors,until my ancestors revolted against your ancestors,thereby achieving their liberty, but ensuring that both races would exist in a state of mutual antipathy. Therefore, since we are in such close proximity, my vow of allegiance to my race compels me to attack your vessel.

UNCLE PATRICK:(spewing forth dribbles of saliva and plastic cup bits, while starting to stand up) What in the name of!! That does it! I qu..

AUNT MOIRA: (soothingly) Fortunately, we’ll still have time to make the final Christmas Eve service.

UNCLE PATRICK: (checked and quieted, returns to a sitting position)

COUSIN SEAN:Not to worry, Uncle Patrick. You can protect yourself against the attack easily enough. (Casting an anxious glance at Aunt Moira.)Don’t worry, Liam won’t ask him a question. He will reveal the first three numbers of a sequence. This is the “attack.” Provided that Uncle Patrick can determine the fourth value in that sequence, he will thwart the attack and continue unharmed. Make sense?

LIAM: I’ll be easy on you, Uncle, as you are not experienced with interstellar combat. Ready?

UNCLE PATRICK produced some sort of sound.

LIAM: Good. Now, here is my attack. First value is 2, then 4, and then 6…..the fourth value of the sequence is…

UNCLE PATRICK: (raising an eyebrow) Eight?

LIAM:WRONG! I’m sorry, Uncle, but the correct answer is 288. You see,in this particular sequence I developed, the fourth value is the sum of the cubes of the first three values. Isn’t that clever?

COUSIN SEAN: (visibly disgruntled) You’ve been rifling under my mattress again.

LIAM:(defiantly)Yeah,and imagine how soiled and corrupt I became when finding nothing but those issues of the American Journal of Mathematics.

COUSIN SEAN: (grunts)

LIAM:So,then, I am terribly sorry, Uncle, but having failed to thwart my attack,your vessel’s integrity is breached. (Reaches over and swipes Uncle Patrick’s $100 bills) This is for repair costs.

UNCLE PATRICK: What?!

LIAM:(Swipes Uncle’s $500 bills) and this is shameless looting by the attack crew. Due to damages inflicted, your vessel is disabled for four turns,allowing the crew enough time to assemble and fire their laser catapult. (reaches over and snaps Uncle Patrick’s left ear and nose) Slavery is wrong!

COUSIN SEAN: Ew! Two direct hits. (To Aunt Moira) I thought he said he was good at Monopoly…

UNCLE PATRICK clamored up frantically, using one hand to cover his ear and the other to nurse his nose.

LIAM(shouting at Uncle Patrick as he stumbles clumsily for the kitchen.) Hey, Uncle,if you quit now, we’re not going to let you play next time!

COUSIN SEAN: Yeah, even if you beg….

Meanwhile, up in the bedroom….

A poet once said that wind chimes were the one instrument enabling mortals to hear air’s music: the secret tones that were the special reserve of the mythical folk who nestled in the hidden places, practicing their silver magic and eschewing all human company. Lying on the bed, with the wind chimes gently whispering, I could almost envision a member of this unseen brotherhood standing on the crystalline ice pastures beyond the bedroom window. Perhaps under Christmas Eve’s warming spell, this creature looked for once with pleasure at our human dwelling. Maybe it saw the glimmer of unexpected benevolence in the candle lit glow of nearby homes and towering church steeples. Drawn by a curiosity that it had always previously quelled, this being may have even moved slowly toward our home, cleaving to the mad hope that its feared occupants might offer fellowship instead of menace. At first, its steps would be tentative, and then more assured as its advance met no resistance. It might feel so empowered that it would wander up to the wind chimes and then onto the window sill, to peer kindly into this suddenly welcoming room of protective giants and soft moon shadow. And, as it perched upon the window, sitting gently upon crossed legs, it would hear the stampede-like reverberation of two human feet and Uncle Patrick’s despairing cry. “Where’s my gun at?!”
It dread of humans once again and forevermore restored, it would flee at once for the distant sylvan corners, to its welcoming community of elusive earth spirits.
Being tired, I decided not to follow, but instead closed my eyes and soon fell asleep.

Merry Christmas
and Happy Holidays

DA December 21, 2009 The Orange’s Zero Obliquity

From the USM Southworth Planetarium
“The goddess is downstairs and magic is afoot”

THE DAILY ASTRONOMER December 21, 2009 The Orange’s Zero Obliquity

For those who haven’t been following these natural cycle affairs, winter begins today at 12:47 p.m. Well, to be astronomically correct, winter begins in the Northern Hemisphere at 12:47 p.m. At the same moment, summer begins in the Southern Hemisphere. We call this event the “solstice,” a word derived from the term “Sun Still,” as the Sun appears to linger in the same low position for a few days before starting its gradual ascent. We have often discussed how alarming this Sun’s seasonal descent was to many of the ancient world’s inhabitants, most of whom realized that the Sun was vitally important to sustaining life. Having the Sun sink close to the horizon induced many cultures to develop elaborate rituals intended to compel the Sun higher in the sky. They knew that death would soon ensue were the Sun to vanish forever. Fortunately, the Sun always proceeded to higher altitudes in the months following the solstice. One can well forgive many of the ancient people for believing that their intervention was responsible for the Sun’s ascent and subsequent warming of the planet. As humanity eventually realized, of course, the Sun would have climbed higher in the sky even without our coaxing rituals.

The Sun’s changing altitude is a consequence of both our planet’s orbital motion and its “tilt.” Caused perhaps by the same impact which created the Moon more than four billion years ago, Earth is tilted relative to the vertical by 23.5 degrees, a value known as “obliquity.” It is not simple to envision a tilted world, especially since all planets revolve in a depth less void where direction and orientation are tricky matters. For those encountering difficulty imaging this concept, envision an orange and a light bulb. Push a toothpick into the orange’s top and bottom. Let’s assume that the orange has a zero obliquity. (i.e. it is upright relative to the light bulb). As the orange revolves around the light bulb, the light from the latter falls evenly on the former during the entire revolution. Now, let’s tilt the orange over by 23.5 degrees. (As this exercise occurs in your mind, determining this precise tilt will prove quite trivial.)
Once the orange has this tilt, imagine that it also revolves around the light. At one point along this orbit, the north toothpick will point as far away from the light bulb as possible. This is the “winter solstice” point: when the north pole is directed away from the light and its angle along the orange’s northern hemisphere is at its lowest. The point on the other side of this winter solstice point is the “summer solstice” position, at which the northern toothpick is pointed toward the light. The light’s angle on the orange’s northern hemisphere is greatest.
Let’s engage our imaginations more and assume a community of microbes resides on the orange membrane. (Not that we’re stretching this analogy beyond all bounds of reason and propriety, you understand.) This northern enclave of microbial orange membrane dwellers do not perceive the orange’s revolution or its angle relative to the light. Their only perception is the light’s angle: when it appears to rise over their east, set in the west; and reach its highest altitude along the meridian: the orange’s meridian extends from true south to true north and divides the sky between eastern and western regions.
The light’s altitude each day varies as a consequence of the orange’s orbital position. When the orange is at the summer solstice position, the light rises well north of east, sets well north of west and attains its highest position along the meridian. When the orange is at the winter solstice position, the light rises well south of east; sets well south of west; and crosses the meridian at its lowest angle.
Let’s further assume that these microbes have little, tiny astronomers with even smaller, atomic CCD cameras capable of capturing images of the light when it crosses the meridian each 11th day. During one year, these itsy-bitsy, microbial astronomers with their little amoeba bowties and horn-rims create an analemma: a figure-eight arrangement of the light at different positions throughout the year. By observing the light’s periodic position shifts during the year, these clever little buggers determine that the light’s not moving: their orange planet is. This orange’s motion causes this light, which they call “the light” (microbes not being known for their creativity), to alter its angles gradually through the year: highest in their summer, lowest in their winter.
Mind you, this conclusion was not reached by just one microbe. Generations upon generations of them (about 2 days) pass before they dispense with ancient superstitious ideas and establish the scientific explanation of the orbiting, tilted orange with the hypothesized polar toothpicks that none of them has yet visited.
This discovery causes them untold relief, as they no longer need to worry about the passing of the light. To them, with their new found knowledge of orbiting oranges and their ignorance of your electric bill delinquency, are secure in the knowledge that the light is eternal. Its descent is all a matter of perspective.
And there was mild rejoicing (microbes not being indefatigable revelers.)

[DA December 18, 2009] Quiz: Stars II

From the USM Southworth Planetarium
“A tickle and a tackle and a smattering of spackle”

THE DAILY ASTRONOMER
December 18, 2009
Quiz: Stars II

Next week, we’ll be all about the holidays! Now, however, we go full force and undaunted into all things stellar. Based primarily on Wednesday’s two part star-soaked birthday card, this quiz is about stars! We call it STARS II because we vaguely recall having posted a stars quiz at one time, although I can’t imagine what would have induced us to do that.
So, before the holiday revels begin, we dive cranium first into
STARS!

(With an acknowledgment to SP!)

1. RIGIL KENTAURUS is
a. The brightest star in the night sky.
b. A star cluster.
c. A star system.
d. Visible only south of the equator.
e. Circumpolar in Portland’s sky

2. Apparent brightness is determined by:
a. Distance and luminosity.
b. Distance alone.
c. Distance and size.
d. Size and luminosity.
e. Mass.

3. GAMMA VELUM is a star that is:
a. Visible during daylight hours in December.
b. Visible during daylight hours in August.
c. Without a proper name.
d. One whose name means the fourth unknown.
e. That is widely used as a guide to finding the constellation Adiorb

4. The Little Milk Dipper is
a.The (more) common name of El Nath, a star in the constellation Taurus.
b. A grouping of stars within Sagittarius.
c. Used to find the North Star (Polaris).
d. A distinct star cluster in the constellation Arcturus.
e. Found by arcing from Arcturus.

5. The brightest star in the night sky is ______________, but is not the closest star to the Sun, which is _________________.
a. Sirius; Antares
b. Canopus; Sirius
c. Sirius; Alpha Centauri
d. Mirfak; Alpheratz

6. Which star’s name means “little king?”
a. Adhara
b. Regulus
c. Shaula
d. Mimosa

7. How many Big Dipper stars appear on the list of 50 brightest?
a. 1
b. 2
c. 3
d. 6

8. Which constellation has the star whose name means “brand on the camel?”
a. Camelopardalis
b. Auriga
c. Octans
d. Gemini

9. Alpha Centauri is the closest star to the solar system, but it isn’t the brightest. How many stars appear brighter than Alpha Centauri?
a. 1
b. 2
c. 3
d. 4

10. The star called ____________, means “the follower” because it appears to follow _________________.
a. Pollux; Praesepe
b. Aldebaran; the Double Cluster
c. Vindemiatrix; the Swan Nebula
d. Aldebaran; the Pleiades

ANSWERS

1. c. A star system.
Rigil Kentaurus (Alpha Centauri) is a ternary star system (containing three stars). Multiple star systems outnumber single star systems, with binaries (two star systems) being the most common type of multiple.

2. a. Distance and luminosity.
A star’s apparent brightness depends upon its actual brightness (luminosity) and distance. A bright star that is quite distant might seem dimmer to us than a relatively faint star that is much closer. Astronomers refer to a star’s apparent brightness as the apparent magnitude (m) and its actual brightness as absolute magnitude (M).

3. c. Without a proper name.
Gamma Velum is the star’s Bayer Nomenclature Designation, which assigns Greek letters to a constellation’s stars in order of relative brightness.

4. b. A grouping of stars within Sagittarius.
The actual term is “asterism,” a group of stars within a constellation. The Big Dipper is Ursa Major is one of the most famous examples.

5. c. Sirius; Alpha Centauri
This is one of those tests in which the answer to one question helps one answer another question.

6.
b. Regulus
Appropriately enough, Regulus is the brightest star in Leo the Lion.

7. c. 3
Dubhe, Alioth, and Alkaid

8. d. Gemini
Alhena is Gemini’s third brightest star. Its name, from the Arabic, means “brand of the camel.”

9. d. 4
The four stars are (in decreasing order of apparent brightness):
Sun, Sirius, Canopus, and Arcturus.

10., d. Aldebaran; the Pleiades

RATINGS

10 CORRECT STAR LORD!!!
Piercing light blue eyes; slicked back hair; mirrored glasses; sculpted abs; wristwatch indicating every cycle from lunar to diurnal with just a touch of aberration; kick-bottom chrome coated throne; and a sprinkle of the UK in your inflections. Too bad that high collared cloak detracts from your otherwise perfect appearance.

7 – 9 CORRECT STAR PROFESSOR!!
Wild hair; cluttered desk; fungus-coated coffee machine; Tom Baker scarf; psychedelic slide rule; a CD player that only plays Rush hits, and a cackling, all too frequent cacchination that makes the Dean want to rescind your tenure.

3 – 6 CORRECT STAR SQUIRE!
. Secretly admiring stars as you rub them, wipe them, pack them, sharpen their spicules and polish their chromospheres. They might seem a bit toffee nosed and self important now, but these stars will be your servants one day. Look at the bright side: your title has an alliteration that your superiors sometimes pretend to envy.

1 – 2 CORRECT STAR SERF?
A muddy, murky,mish-mash of mulching and muck. Why I ever signed up for that cruise to the 12th century beats the devil out of me. Accursed pamphlet!! “Two whole weeks in a charming medieval village where you and your soulmate can rekindle lost romance amidst the jolly fragrance of putrefaction.” Spike balls, plague spores and the locals with their various interpretations of appropriate hygiene. Where’s my damned copy of “Ivanhoe?”

0 CORRECT: The irksome thing is that we don’t know what seasonal greeting to use with people. You say, “Happy Holidays,” and the person will often gulp and insist that you wish him a “Merry Christmas.” Wish a person a “Merry Christmas,” and she’ll ask you to be more inclusive and say “Happy Holidays.” We got it right once, when that guy came in with the inverted pentagram forehead tattoo, spiked hair, leather jacket with dangling chains, and contacts glowing red. Then, a simple “Have a nice day. By the way, I’ll bet that jacket makes a lot of noise in the dryer,” proved appropriate.

[DA December 17, 2009] No, that’s not Santa!

From the USM Southworth Planetarium
“What a lame tag line that is…”

THE DAILY ASTRONOMER
December 17, 2009
No, that’s not Santa!

***************************************
See the ISS in the sky;
See the ISS at the planetarium.
We’ve just erected an International Space Station model
above the planetarium’s entrance.
If nothing else, the ISS model makes us easier to
find: just look for the stairs between the ISS
model and the Saturn mural.
Venture downstairs and find that miracle of
ill-advised inspirations called the Southworth
Planetarium.
*****************************************

As yesterday’s DA might have been a nanometer over the top, today we’ll go low-key with an advanced ISS alert. Specifically, this particular ISS passage happens on Christmas Eve morning. It will be so sky-high and spectacular that one might well mistake it for ol’ Saint Nick, himself!

We know that many fly-bys occur before this event, but we want to give our readers plenty of time to prepare for this brilliant sighting.

The International Space Station appears as though by black elven magic almost overhead at 5:25:39 a.m. on Thursday, December 24, 2009. To be more accurate, it will be 80 degrees above the horizon, close to the Big Dipper’s Bowl. For almost five minutes, one can observe the station descending toward the southeast, in the direction of Libra/Ophiuchus. During this passage, the ISS will appear 2.5 times brighter than Jupiter and six times brighter than Sirius.

During its trek, one can see the ISS just north of Arcturus, the brightest star in Bootes the Sheepherder.

At 5:28:22 a.m, the ISS will be 10 degrees above the southeastern horizon.
At 5:30:21 a.m. it will set, at which time it will be overhead hundreds of miles east of Maine’s Atlantic shoreline.

We see the International Space Station because it reflects sunlight. The angle between the ISS and the Sun has to be small enough so that the reflected sunlight reaches our eyes. It is for this reason that we cannot see the ISS at midnight. One finds it either in the early evening or early morning. Presently, the ISS is a beautiful pre-dawn sight, but will soon return to the evening.

“Solstice Dawning” Celestial Poetry Evening Friday!

Ladies and gentlemen,
the USM Southworth Planetarium
invites you to attend our
next celestial poetry evening!

Friday, December 18, 2009
7:00 p.m.

“SOLSTICE DAWNING”
a wonderful blend of poetry, stories,
stars and the Universe. Hear
writers read poetical works (theirs
and others) about nature, love, mythology,
stars, and everything else that one
tends to find in prose and verse.

Experience the magic of words beneath
a dome of stars, floating moons, spinning
galaxies, and an array of other celestial images.

We’re posting this reminder because
today’s Portland Press Herald featured
a story about the event and reservations
are coming in –in trickles, if not torrents…

If you want to reserve your space for this poetry evening,
just send a reply with your name, telephone number
and the number of tickets you’d like to reserve.

Admission by donation.

For more information, call 207-780-4249,
or just send me an e-mail.

Cheers!
Edward

[DA December 16, 2009] 50 (Part II)

THE DAILY ASTRONOMER
December 16, 2009

50
(Part II)

The list of the FIFTY brightest stars continues….

BELLATRIX
The Amazon Warrior star adorning Orion’s western shoulder. While most know the name because of Bellatrix LaStrange, Harry Potter’s truly wicked witch. Those who find this character to be appealing will have no trouble remembering that Bellatrix is special because it is one of the hottest stars visible to the naked eye. Its high “surface” temperature of 22,000 degrees makes it a truly bright star. A star’s energy output, or luminosity, depends upon its size, mass and temperature. While Bellatrix is not a highly massive star, it is hot enough and close enough (250 light years) to place it neatly in the center of our top fifty list.

EL NATH
El Nath represents Taurus the Bull’s horn tip. Taurus’ beta star is far outshined by the alpha star Aldebaran. What distinguishes El Nath is that it is a lynch pin star, one that has been associated with another constellation. Some charts link El Nath with Auriga, the charioteer constellation to the north of Taurus and Orion. Very few prominent stars are shared by two constellations, however. Perhaps the most famous example is Alpheratz, the northeastern corner star in Pegasus that is actually considered part of Andromeda, the chained princess.

MIAPLACIDUS
Now, that is a name! Not that we’re truly sure what it means. Those who study word origins believe the term derives from “gentle waters,” as the star is in Carnina, the Keel. Years ago, a large ship adorned the southern skies. Called Argo Navis, this vessel was said to have conveyed the Argonauts in their quest for the Golden Fleece. This ship has been divided into four different constellations: Carina, Puppis, Vela and Pyxis.

ALNILAM
“The belt of pearls.” The center star in Orion’s belt doesn’t garner the press coverage it deserves, perhaps because it is just one of Orion’s belt trio: the three lovely sister stars Alnitak, Anilam, and Mintaka. Each Orion belt star is quite distant, but Alnilam is the farthest away (1340 light years). Despite its greater distance, Alnilam still appears brighter than its sisters because it is so intrinsically brilliant (370,000 times brighter than the Sun.) If Anilam were as close as Mintaka (915 light years), it would certainly rank higher than Orion’s 4th brightest star.

AL NA’IR
This is the very first time the DA has mentioned the constellation Grus. Strangely, Grus represents a crane. The term Grus americana is the technical name for Whopping Crane. Once part of Piscis Austrinus, Grus was a creation of Petrus Plancius (1552-1622), who fashioned a dozen constellations out of faint stars. Only a few remain on the charts today. As it was once part of the southern fish, Al’Nair’s name means “fish’s tail,” even though it now marks the crane’s leg. For those of us around 43 degrees north latitude, Al Nair is just barely out of sight, visible only to those at or below 41 degrees north latitude.

ALIOTH
The curve in the Big Dipper’s handle, or the handle star closest to the bowl. The three handle stars in the Dipper are Alioth, Alcor-Mizar, and Alkaid at the handle’s end. Alcor-Mizar mark the handle’s bend. Alioth is part of the Ursa Major Moving Cluster, an open star cluster at a distance of approximately 75 light years. Over thousands of years, the Big Dipper will dissipate as Alkaid and Dubhe, neither of which belong to this cluster, slowly migrate away from the others.

GAMMA VELUM
It is curious that a top 50 star has no proper name. (We’ll encounter two examples of these.) Yet, no proper name has been recorded for this star. We must admit that the star names we have today derive from western civilization sources, which list precious few names for stars visible primarily in the southern hemisphere. Instead of a proper name, we have the star’s Bayer Nomenclature Designation. (See Gacrux) So, Gamma Velum is the brightest star without a proper name.

MIRFAK
Perseus’ brightest star is not its most famous star. Algol, the eclipsing binary representing Medusa’s eye, is much better known. One can find Mirfak within the stick figure shape of Perseus. Astronomically, Mirfak is notable for being a supergiant (quite rare) and the brightest member of the ‘Alpha Persei Cluster,” an open cluster of stars only about 52 million years old. Open clusters are relatively young collections of gravitatioally bound stars. They are smaller and much younger than the other principal star cluster type, the globulars, which lurk in the halo, a spherical region centered on the galactic nucleus.

DUBHE
We like Dubhe because it is one of the “pointer stars,” those two stars that direct us to the north star Polaris. Dubhe is the corner star in the Big Dipper’s bowl. By drawing an imaginary line through the bowl’s outer stars, Dubhe and Merak, one can find Polaris, which is about a dipper’s length away.

WEZEN
The third brightest star in Canis Major, Wezen is one of the truly “young ones,” being a star that formed about 10 million years ago. It has already ripped through its core hydrogen and is presently gathering enough heat to fuse helium. Like all massive stars, Wezen expends its nuclear fuel rapidly, unlike the Sun, which gradually burns through its fuel allotment over billions of years.

KAUS AUSTRALIS
Sagittarius is the archer aiming his arrow at Scorpius the Scorpion. Kaus Australis is that star in the arrow’s tip. Star names are so fascinating because they derive from a variety of sources, such as Greek, Latin and Arabic. The name “Kaus Australis” means “bow of the south.” One might recognize the Latin word “south” embedded in Australis. The southern lights are called the aurora australis. Remembering star names is an effective way of memorizing Latin, Greek, and Arabic direction and body part terms.

AVIOR
Some star names are quite ancient, dating as far back to the days of the Sumerians. Others are of much more recent vintage. The name “avior” was assigned to this star during World War II. The term refers to the pilots using the stars in their navigation. Being quite far south (not visible to those south of 28 degrees north latitude), it did not receive any proper name noted on any starchart. It is the brightest of the “ignored” stars.

ALKAID
The Big Dipper is well represented on this list. Alkaid is the end star in the Big Dipper’s handle. It also represents the great bear’s tail. It is curious that so many different cultures saw this pattern as a bear. Some native Americans referred to the dipper’s bowl as the bear. The handle stars were three hunters pursuing the bear, with Alkaid taking up the rear. The name Alkaid has no relation to bears, however. The name means “the leader,” for these stars were seen by Arab astronomers as the three daughters attending their father’s funeral: the bowl being the tomb.

SARGAS
Sargas, marking the Scorpion’s underbody, defines our southern horizon. As it lurks so close to the horizon, Sargas was used an indicator star: one whose visibility attested to clear southern sailing. Sargas is another star with a mysterious name, one most likely of Babylonian origin. Sargas is a Cepheid variable: a star that expands and contracts with a regular period. These stars are brilliant distance indicators since their variability period relates to their intrinsic brightness. By observing how much time a Cepheid requires to complete one variability cycle, one can measure its absolute brightness. Comparing this value to its apparent brightness yields its distance.

MENKALIMAN
Do you think Menkaliman is a strange name? Well, it’s better than solstitial colure, a construct with which it is associated. What the devil is the “solstitial colure,” you ask. It is the great circle that passes through both celestial poles and the two solstice points (Winter and Summer) You see, the Winter Solstice point is in Sagittarius; the Summer Solstice point is in Taurus. If you drew a circle between the North Celestial Pole and the South Celestial Pole so that it passes between both of these points, you’d draw the solstitial colure. Menkaliman, the second brightest star in Auriga the Charioteer, marks the solstitial colure’s location, in much the same way that Polaris marks the North Celestial Pole’s approximate position.

ATRIA
The sky is replete with triangles. One can make triangles almost everywhere. All one needs, after all, is a set of three stars. There are a couple official triangles in the sky: Triangulum and Triangulum Australe. (As we can guess, the latter one is the southern triangle) This triangle is WAY down there, ladies and gentlemen. It isn’t even visible on the Tropic of Cancer. One has to be south of 20 degrees north to find it. Atria is so far south, it is one of the brightest stars close to the South Celestial Pole. Needless to say, we northern dwellers don’t have a chance to find it.

ALHENA
Let’s take a moment to explain the “Al,” which is common in star names. Many stars were named by Arabic astronomers. These names often contain the prefix “al,” the Arabic word for “the.” Alhena is one such example. Even though it is Gemini’s third brightest star, Alhena means “brand on the camel.” Arabic astronomers did not see the Gemini stars as twins, but as a camel procession. One can find a great deal of incongruity between the names of constellations and the stars that comprise them. This is because we have a rich mish-mash of cultures that have left their imprints on the star charts.

PEACOCK
And, speaking of star names, how interesting it is to find a star name in English! The Peacock is the alpha star in Pavo, the Peacock. Another constellation that is far south of us, Pavo is a modern star pattern with an ancient association. Formed by Dutch explorers, Pavo represents Argos after Hera transformed him into a peacock after conveying his vessel the Argo Navis to the sky. As Pavo is near the four constellations made from the Argo Navis, its inclusion is quite logical, mythologically.

DELTA VELORUM
The other stars on the top 50 list that doesn’t have a proper name. Delta Velorum is in Vela, part of Argo Navis. Those venturing into the southern hemisphere in search of the Southern Cross be warned: there is such a thing as the “false cross,” an asterism within Vela. It resembles the southern cross as it consists of two perpendicular star lines. However, it is larger than Crux (the smallest constellation) and consists of fainter stars. Delta Velorum is in this false cross. Vela is the southern pole constellation on Mars, the star Kappa Velorum being only a couple degrees away from the Martian SCP.

MIRZAM
Canis Major’s beta, but fourth brightest star. Yes, if you’ve been reading these little sections, you will remember that the Bayer system assigns Greek letters to a constellation’s stars in order of relative brightness. However, the system is often inaccurate, as it was designed years before modern brightness determination equipment was invented. Like most of Canis Major’s other bright stars, Mirzam is in the dog’s head. Though it is much dimmer than Sirius, when Mirzam eventually explodes as a supernova, it will be as bright as a galaxy for a brief time and will outshine all the other stars. Of course, this fleeting fame will come at the cost of its life, but for some, being notorious is preferable to being extant.

CASTOR
The second brightest star in Gemini; also the name of the mortal twin. Castor is a six star system (two inner pairs of white stars around which revolve an outer red dwarf pair.) This star is a historical stepping stone, as it was the first place outside the solar system where astronomers could observe motion induced by gravity. As they determined that Castor’s component stars moved in accordance to Newtonian laws, it helped us realize that gravity works all over the Universe.

ALPHARD
The “solitary star.” It occupies the region close to Regulus, but is the one prominent star in a dark part of the sky. Though it is low on our list, Alphard is still the brightest star in Hydra, the many-headed watersnake. Hydra, like Eridanus, is one of those meandering constellations consisting of relatively dim stars that, nevertheless, form a discernible procession across the heavens.

HAMAL
The brightest star in Aries the Ram. Whereas we’ve seen prominences on Betelgeuse, we’ve observed a phenomenon called “limb darkening” on Hamal. Limb darkening is the apparent darkening visible along the limbs (outer edges) of the Sun. We perceive such darkeneing because when we observe the sun’s outer edges, we’re peering through a thicker section of gases than we see in the Sun’s center. Thus, the solar limbs seem “shadowed” As Hamal is a close star (15 light years), similar edge diminishment is also observable.

NUNKI
Have you ever heard of the “Little Milk Dipper?” Well, let us tell you that it is one the night sky’s hidden gems. Like the Big Dipper, the Little Milk Dipper is an asterism (a star pattern contained within a larger constellation.) This Little Milk Dipper is part of Sagittarius the Archer. Sagittarius is steeped in the Milky Way Galaxy’s glow, as the constellation is aligned with the region marking the galaxy’s center. In this part of the sky field we encounter wide swaths of brilliant star light. The Little Milk Dipper is a five star asterism that appears upside down to us, as though it were pouring milk out onto the shimmering stars below it. This dipper encompasses Sagittarius’ northern portion. Nunki is the northern star in this asterism.

POLARIS
Yes, you have to wait until you reach the list’s bottom to finally encounter Polaris, the north star. As it has the name recognition that most other stars do not enjoy, people naturally assume it’s the brightest. However, it barely makes the top 50. Polaris is currently the north star because Earth’s northern axis is aligned close to it. The star barely appears to move during the night and always marks north. Eventually, precession (Earth’s wobble) will shift Polaris away from his position, allowing for other stars to eventually become the north star. In fact, Vega will become the north star 13,000 years from now.

DENEB KAITOS
The Whale’s Tail is the tail end of today’s two-part DA. Deneb Kaitos, also known as Diphda, marks the tail of Cetus the Whale (or sea monster) Cetus was the monster released by Posideon to destroy Cassiopeia’s village after the latter insulted the former by declaring that the latter’s daughter was more beautiful than the former’s sea nymphs. It’s an ancient story that needn’t be rehashed here. Suffice it to say that all ended happily for everyone, except Cetus. Take note of the word “deneb,” meaning tail. We see that a few times in star names, such as Deneb, the tail of Cygnus the Swan and Denebola, the Lion’s tail.

Happy Birthday again to my brother Richard.
We’re all glad you’re not turning 100.

[DA December 16, 2009] 50 (Part I)

From the USM Southworth Planetarium
“Heavens above, what was that?!”

THE DAILY ASTRONOMER
December 16, 2009
50
(Part I)

Every star has a story. That is why we love stars so much. Though, like snowflakes, they appear interchangeable when viewed from a distance, stars reveal distinct characteristics when closely examined. Discovering these distinctions is no easy task: we see thousands of stars in the night sky; billions in the galaxy; and trillions in the universe. It is fortunate that we cannot resolve most stars in distant galaxies, because the stars we can observe provide plenty of work for everybody.

So, today we offer a list of the night sky’s fifty brightest stars. You understand, today is a special day and we have the number FIFTY on the brain. When deciding on what list of FIFTY we should compile, we decided on the FIFTY brightest stars. A list of the FIFTY closest stars would be rather unexciting, as most of these FIFTY are not visible without telescopes.

We toyed with the idea of listing our FIFTY favorite stars. However, such a list would require us to place a star at the number one position. That’s a problem, as we’re like Don Juan when it comes to stars: “If you’re true to one, you’re cruel to all the others.”

We opted finally for the brilliant and beautiful with this list of FIFTY apparently brightest stars in the sky. Northern inhabitants can see most of them and many are well placed this time of year.

Instead of being encyclopedic about this list, however, we wanted to mention something interesting about each one: a little factoid or tidbit that makes the star (or at least our perception of the star) quite fascinating, as all stars truly are.

Before I start, however, just a quick shout out to my brother, who celebrates a birthday today. However, being a person of class, I won’t divulge his age. That disclosure would be impolite.

SUN
a beautiful star, though not large when compared to its big brothers. Sustains our lives and is delightfully photogenic. Should live for billions more years, and will eventually become a bloated red giant. It will be bad news for Earth when this expansion occurs, but we won’t be around to enjoy the catastrophe.

SIRIUS
King of the hill as far as the night sky is concerned. Sirius is brighter than the rest, though often out shined by the planets Venus and Jupiter. This star used to be a household name, until falling out of public consciousness for while. Fortunately, JK Rowling renewed its fame.

CANOPUS
The “other” truly bright star. Don’t worry if you’ve never heard of it, as it is not visible to those in the mid-northern latitudes. Canopus is the alpha star in the southern hemisphere constellation of Carina the Keel.

ARCTURUS
The truly bright northern sky star. It lent its name to Earth’s cold northern region, “the Arctic.” One can find Arcturus by sliding down the Big Dipper’s handle, hence the famous mnemonic “Arc to Arcturus.” Arcturus is a “slicing” star, as it is slicing across the galactic plane at a rapid clip and will vanish from our skies in half a million years.

RIGIL KENTAURUS (ALPHA CENTAURI)
Well, determining this star’s distinction will be difficult. Rigil Kentaurus is also known as “alpha Centauri,” the brightest star in Centaurus. Visible only in regions south of 30 degrees north -but best seen at or below the Tropics- Alpha Centauri is the closest star system to our Sun. We call this a star system, as it consists of three stars: two sun-like stars, Alpha Centauri A and B, and an outer red dwarf star, called Proxima Centauri.

VEGA
Summer’s beacon star. Vega, the Summer Triangle’s brightest star, marks Lyra the Harp’s northern tip. To those around 40-45 degrees north latitude, Vega is visible for at least a part of the night each day of the year, even though it isn’t circumpolar. “Vegan” stars are those non-circumpolar stars which are so high in the sky that they are visible for at least a part of the night each night.

CAPELLA
Capella is also a “Vegan” star. Poised high in Auriga, the pentagon-shaped constellation north of Orion, Capella is the “goat star,” located just north of a faint grouping of stars called “the kids,” or young goats.

RIGEL
Orion’s brightest star marks Orion’s knee. It is a blue supergiant star at the southwest of Orion’s rectangular outline. Three of these four rectangle stars are on this list. The Bayer Nomenclature system (see Gacrux) indicates that Rigel is not as bright as Betelgeuse, but that is an error. While Betelgeuse runs a close second, Rigel is the most brilliant of all the bright Orion lights, and believe you me that’s saying something.

PROCYON
Poor Procyon! It can never escape Sirius’s shadow. Procyon is the bright star in the two-star stick called “Canis Minor,” the little Dog. Procyon is the Ron to Sirius’ Harry: a star that is famous only for its association with a more well known star. The name Procyon means “before the dog,” as it rises a few minutes before Sirius. It is the opening act for the main event; the animated concession snack band before the film; the countdown before the Times Square apple drops; and we’ve had to exhaust all our analogies just to fill a paragraph about this underappreciated star.

ACHERNAR
The end of the river, the river Eridanus, that is. This great, meandering river constellation begins at Orion’s knee and ends far in the southern sky with Archernar. We can’t see it here in the north. This star is a trick because it is shedding its matter at a stunning rate: more than a thousand times greater than the Sun’s mass loss. This rapid and continued material expulsion makes it difficult for astronomers to determine the star’s physical properties. All stars are energetic and hyperactive in their own regards, but this one is bursting on all eight cylinders.

BETELGEUSE
Big, bad, bold, beautiful, brilliant, bloated Betelgeuse. If someone came up to us and said, “choose a favourite star or I’ll smash all your Mannheim Steamroller Christmas CDs”, we might just select this star as our main squeeze. What’s not to love about a star that resembles a fire opal! Marking Orion’s eastern shoulder, Betelgeuse is a red supergiant that could swallow more than 150 million Suns, if it developed a taste for unflavored plasma. While its translated name “giant’s armpit” is hardly an endearing term, Betelgeuse is the mammoth sphere that puts a crimson flare in our crisp winter sky. It is about 520 light years away. It if were just a couple of hundred light years closer, it would be high on this bright star list! Even at its ranking now, though, Betelgeuse rocks.

HADAR
Let’s pretend we’re in the southern hemisphere during their early spring (our autumn). High in the evening sky one can see the magnificent Southern Cross, also known as ‘Crux.’ Just to the east of Crux is Beta Cenaturi (Hadar) and to the east of Hadar is Alpha Centauri (Rigil Kentaurus). The mnemonic is Alpha-Beta-Crux. Like its constellation companion Alpha Centauri, Hadar is among the brightest. However, at a distance of 390 light years, it is almost 100 times more distant than Alpha Centauri. Here we encounter one of the night sky’s most effective deceptions: the concealment of depth. Alpha and Beta Centauri seem locked arm-in-arm, even though the former is poised on our shores, while the latter is far off on the horizon.

ALTAIR
Imagine a star that resembles a blue egg and you’ll see Altair. The star marking the Summer Triangle’s southern tip is one devil of spinner, as it rotates once every 8.9 hours, as opposed to the Sun’s comparatively lethargic rotation rate (25 days at the Equator; 32 days at the poles.) Because Altair spins so rapidly, it bulges out dramatically at its equator, making it look like an egg. As it is a hotter star, it glows blue-white, hence the “blue egg” appearance. Altair, being so close at a distance of 16 light years, is one of the few stars that astronomers can directly image. These images have verified one of astronomy’s somewhat more advanced theories, called the Von Zeipel effect. The Von Zeipel theorem states that a star’s effective temperature is affected by its surface gravity. The stronger the gravity the higher the temperature: Altair’s equator, being a bit farther out from the center than other regions, has a lower surface gravity and should be cooler, therefore slightly dimmer, since temperature and luminosity are related. And, indeed, this gravity darkening (Von Zeipel) effect has been observed on Altair.

ALDEBARAN
So, we admit it, we LOVE this star. Not only because of the enchanting Enya song of the same name, but because it is the follower star: the star that follows the Pleiades star cluster across the sky like an adoring lover. The name Aldebaran actually means “the follower” for this very reason. It marks Taurus the Bull’s orange eye, the one glowering down at Orion, who has pursued the fleeing sisters with the same earnestness with which Aldebaran trails them. It’s lovely to be admired, isn’t it?

ANTARES
Rival to Mars! Well, that is what its name means. It is Mars’ rival because of its red color. A star’s temperature determines its color: Antares is red because it is a cool star, with an effective temperature of 2,300 degrees. Mind you, this temperature is blisteringly hot by planetary standards, but, as far as stars are concerned, is rather tepid. Antares marks the heart of Scorpius the Scorpion, a constellation currently lost in the solar glare.

SPICA
Remember the mnemonic “Arc to Arcturus?” It has a second verse. “Arc to Arcturus; Speed to Spica.” Found south of Arcturus, Spica marks Virgo’s hand. Spica has been corn, wheat, or another agricultural staple, for Virgo is the daughter of Demeter, goddess of the harvest. Finding Spica is handy as it is the one prominent star in the long and relatively faint constellation Virgo.

POLLUX
Pollux is the immortal Gemini twin and the constellation’s brightest star. Mythologically, Pollux and Castor had the same mother, but different fathers. Pollux was sired by Zeus, the Greek god king. Having been Zeus’ son, Pollux was immortal, while his brother Castor was not. When his brother was slain in battle, Pollux approached his father and offered to give his immortality to his Castor. So touched was Zeus by this gesture, that he offered both brothers a place in the sky where they could be together for all eternity. Pollux is the star south of Castor.

FOMALHAUT
We have something special to say about this “mouth” star. Marking the mouth of Piscis Austrinus, the “southern fish,” Fomalhaut is not only noteworthy for being a bright star in our southern Autumn skies, but its planet was the first exo-planet ever directly observed. This planet is three times more massive than Jupiter and is almost three times farther away from Fomalhaut than Pluto is from the Sun. It is because the planet is so distant from its parent star, which is also close to us (25 light years) that it could be imaged with present day technology. We’re likely to observe many other exo-worlds, but Fomalhaut’s will always be the first ever “seen.”

MIMOSA
The brightest star in the Southern Cross is not its alpha star. The Bayer system (see Gacrux) indicated that Mimosa was fainter than the cross’ alpha star, Acrux. However, modern observations reveal that Mimosa (at magnitude 1.25) is slightly brighter than Acrux (magnitude 1.33). Astronomers use the magnitude system to measure the brightness levels of different celestial objects. The brighter the object, the lower the magnitude number. Mimosa and Acrux are so close in apparent brightness that the Bayer Nomenclature mistake is quite pardonable.

DENEB
Sometimes life isn’t fair. Vega is much brighter and gets so much attention, but Deneb is far brighter than Vega when their actual luminosities are compared. Deneb is 60,000 times brighter than the Sun, because it is also 1600 light years away, so it seems dimmer than Vega, which is merely 26 light years distant. If Vega and Deneb traded places, Deneb would not only be the night sky’s brightest star, but it would cast a shadow on us at night and would be visible during the day!

ACRUX
The “Southern Cross” is actually called Crux. This cross is famous because its longer axis points to the South Celestial Pole, a spot with a dirth of bright stars. (Sigma Octans marks the south celestial pole, but being barely visible, does not serve as a convenient marker.) While it is best to see the Southern Cross in the southern hemisphere, one can still observe it peeking above the southern horizon as far north as Florida. Yet, even here it is difficult to see.

REGULUS
The “Little King” representing Leo the Lion’s heart. One can also see it as the point under Leo’s sickle, “backward question mark.” Like more than half of the night sky’s stars, Regulus is a multiple system. Were one to visit Regulus, one would find four component stars. While binaries are somewhat common, quadruples are rare. When viewed telescopically, Regulus reveals three stars. One of these three is a spectroscopic binary, two stars so close together as to be optically unresolvable. Only by examining shifts in the stars’ spectra are astronomers able to determine the presence of two stars.

ADHARA
Sometimes we don’t know why stars have their given names. Adhara, the second brightest star in Canis Major, is the leg star in Orion’s faithful hunting dogs. The name “Adhara” means “the virgins,” as the three star triangle around Adhara was once called by the name “virgins.” One can only speculate as to the origin of this name. During the many centuries that have elapsed between the days when stars were first given recorded names and our modern day, much knowledge has been lost and many legends forgotten. The appeal of Adhara is that this star’s name is all that remains of these wholly unknown celestial virgins.

GACRUX
Here we have a moment to mention the Bayer Nomenclature System, which lists the stars within a constellation according to brightness. Developed by Johannes Bayer (1572-1625), this scheme assigns the Greek letter alpha to the constellation’s brightest star; beta to the second brightest; gamma to the third brightest, and so forth. Gacrux is merely a contraction of the term Gamma Crux. Although, to be proper, Caesar, the actual star name must be formed by the Greek letter and the Latin genitive of the Host constellation name, so it would be Gamma Crucis. And, of course, everybody cares deeply about this issue.

SHAULA
“The Stinger Star” in the Scorpion’s tail. Though listed as Lamba Scorpii, Shaula is Scorpius’ second (not eleventh) brightest star. Shaula is called a “heat valve” star, more properly known as a Beta Cephei type variable. These variables expand and contract due to a layer of metals that behave like heat valves, causing fluctuations in heat transfer from the hotter inner regions. The magnitude difference during these variability periods, however, is slight, noticeable only with equipment much more sensitive than the human eye.

[DA December 15, 2009] Of Children and the Sky

THE DAILY ASTRONOMER
December 15, 2009
Of Children and the Sky

Today’s article is equipped with both a long and short version, the latter of which should appeal to those who find these columns to be horrid verbiage torrents. The long version is, appropriately enough, the entire article. The short version is merely the article’s final two sentences.

The article itself pertains to what must be one of the most commons questions posed to planetarium astronomers: “How can I get my child interested in astronomy?”

We cannot answer for your child, whose intelligence and talent are unique. What we can do is to tell the story of an unnamed planetarium astronomer whom we’ll call Xavier, because I’ve always wanted that name.

One brilliant autumn evening, Xavier brought his five year old son out back to admire the night sky. Elated at being allowed out at night, said son bolted to all four fenced-in corners, fetching out nymphs and nasties alike from this unexplored wonder realm. Xavier chased him in earnest, determined to enrich his brain with well rehearsed speeches about Pegasus, worlds spinning in a void, distant stars, and how fantastic it all is.

After his son eluded his fifth capture attempt, Xavier stood still and, in the tradition of all insufferable pedants, spouted his knowledge so as to cover a wide sphere stuffed with rapt listeners. Of course, while his son played in moon shadows, Xavier found himself only with an audience of crickets, some of whom no doubt lapsed into a grateful sleep.

After finally abandoning the effort as hopeless, Xavier embarrassed himself with a game of tag. Once, during a respite to allow Xavier time with an oxygen tank, the son looked up and asked, “Does anybody live on the Moon?”

“Yes. The Moon is the place where the monsters under your bed come from.”

“Neat.”

The son and father then forgot all about the sky above and focused on the moonlit world below. The father learned much more from this excursion than his son did that night. He discovered that for a child, a cosmos of play and mystery is as powerful as an adult’s universe of inquiry.

Sometimes, the wondering child grows into a scrutinizing scientist. Sometimes not. Xavier realized that a person has, thankfully, only a limited influence on another person’s universe. Thus, bringing us neatly to the article’s entire point:

How can you get your children interested in astronomy?

Let them play under the stars.

[DA December 14, 2009] The Great Found Bear

From the USM Southworth Planetarium
“The circle in the center of our block”

THE DAILY ASTRONOMER
December 14, 2009
The Great Found Bear

The night sky is a magnificent timepiece, provided one knows the tricks in using it this way. One can determine the time by night sky observing because of the stars, which are consistently in the same place during each season.

For instance, Orion rises around 7 p.m. in mid-December this year. It rose at the same time in mid-December for many years in the past and will continue to do so for many more years. Over time, however, Orion’s position will shift due to precession (Earth’s wobbling axis.) Over a human lifetime, this effect will be slight, amounting to little more than a degree. Therefore, we can say that for the rest of our lives, we will find Orion rising around 7 p.m.

So, if you’re out in mid-December with someone you’re trying to impress, you can glance over Orion’s shoulder stars above the eastern horizon and confidently proclaim. “Hey, it’s approximately 7:00 p.m.” (Or, you can say “By scrutinizing the night sky, dearest, I have ascertained that it is 7:14 p.m. or thereabouts.” Making this remark requires a dose of pretension and a handy luminescent timepiece that you can whip out of concealment without dearest becoming the wiser.)

The problem with using Orion to tell time is that this constellation is not always around. Sure, it is visible nearly all night this time of year, but in September, it is only up after midnight. In May, it sets soon after sunset. In June, July and part of August it is out of our night sky altogether.

We’d be well advised to use circumpolar constellations: those that never set. Fortunately, mid-latitude skies have plenty of circumpolar star patterns, such as Ursa Major, the Great Bear. You might be more familiar with its famous asterism, the seven-starred Big Dipper. For those living around 40 – 45 degrees N latitude, the Big Dipper describes a wide circle through the northern sky. When at its lowest altitude, the Big Dipper rests neatly on the northern horizon. Ursa Major reposes on this horizon around 6 p.m. during early December, much to the chagrin of Dipper admirers with obstructed or light polluted northern skies.

With this little information, we’ll know how to use the Big Dipper timepiece trick.

The Big Dipper clock

We must understand first that the Big Dipper completes one “circle” every 23 hours and 56 minutes. Its completion time is not exactly 24 hours because Earth moves a bit in its revolution during every rotation cycle, displacing the stars slightly with each sky turn. (This is why non-circumpolar stars rise four minutes earlier each day.) This four-minute difference amounts to one hour every week and two hours a month.

So, here’s the rub: the Big Dipper is on the northern horizon around 6 p.m. in early December, then it will occupy the same position at 4 p.m. in early January. By 6 p.m early January, the Big Dipper is just off the horizon toward the northeast. (around the 5 o’clock position) In early February, the Big Dipper is on the northern horizon at 2 p.m., by 4 p.m. it’s in the 5 o’clock position and by 6 p.m. it at the three o’clock position.

Just use the two-hour rule for the other months: In early March, the Great Bear rests around noon; Early April – 10 a.m.; Early May – 8 a.m., and so forth.

Now, it is a simple matter to know when one will find the Great Bear at its highest point – 12 hours after it is at its lowest point. (This relation makes sense if one remembers that the Bear completes a circuit almost once every 24 hours; so it completes half a circle in 12 hours.) In early December, the Great Bear is at its culmination (highest point) at 6 a.m.; 4 a.m. in early January; 2 a.m. in early February.

While having a planisphere (in your hands or on your wrist) is handy, using simple time tricks like this one with the Great Found Bear make it easier to follow the stars through the sky.