VEGA, ALTAIR AND DENEB

OH MY!

JAMES:
HEY THERE STAR GAZERS.

I'M JAMES ALBURY, DIRECTOR OF THE KIKA SILVA
PLA PLANETARIUM IN GAINESVILLE, FLORIDA.

DEAN:
AND, I'M DEAN REGAS, ASTRONOMER FOR THE CINCINNATI

OBSERVATORY.

WERE HERE TO HELP YOU FIND YOUR WAY AROUND
THE SKY.

THIS WEEK WE WANT YOU TO KICK BACK AND RELAX
UNDER THE STARS

JAMES:
SUMMER OFFICIALLY BEGINS AT THE END OF THIS

WEEK AND THOSE WARM EVENINGS ARE PERFECT FOR
LYING IN THE GRASS AND

LOOKING UP.

DEAN:
THE BRIGHTEST STARS OF THE SEASON ARE OVERHEAD.

JAMES:
THERE YOU'LL FIND A TRIANGLE OF THREE CELESTIAL

DAZZLERS - THE STARS OF THE SUMMER TRIANGLE
NAMED VEGA, ALTAIR, AND DENEB.

DEAN:
AS SUMMER BEGINS, LET'S TAKE A CLOSER LOOK.

DEAN:
OKAY WE HAVE OUR SKY SET UP FOR 11PM ANY NIGHT

THIS WEEK
FACING EAST.

YOU'LL SEE 3 BRIGHT STARS THAT REALLY STAND
OUT.

ITS A TRIANGLE.

ITS RISING IN SUMMER.

SO I'D CALL THAT A
SUMMER TRIANGLE.

JAMES:
LET'S FOCUS IN ON THOSE 3 STARS, AND FLY IN

FOR A CLOSER LOOK.

DEAN:
NO MATTER IF YOU LIVE IN THE COUNTRY OR THE

HEART OF A CITY, YOU SHOULD BE ABLE TO FIND
THESE THREE STARS DISTINCTLY IN THE SKY.

WHEN YOU CONNECT THEM WITH LINES THEY FORM
A HUGE TRIANGLE OVER 30 DEGREES LONG AND 20

DEGREES HIGH.

JAMES:
REMEMBER THE EASY WAY TO MEASURE DEGREES

IN THE SKY?

YOUR FIST AT ARMS LENGTH IS ABOUT
10 DEGREES.

SO SEE IF YOUR SUMMER TRIANGLE IS TWO FISTS
HIGH AND THREE

FISTS LONG.

DEAN:
THE BRIGHTEST STAR OF THE THREE, AND THE ONE

CLOSEST TO THE ZENITH JUST AFTER SUNSET IS
CALLED VEGA.

JAMES:
DO I DETECT A SLIGHT BLUE-ISH TINT TO

THIS STAR?

DEAN:
YOU SURE DO.

VEGA IS A BLUE-WHITE GIANT STAR AND THIS TELLS
US ITS TEMPERATURE.

BLUE IS HOTTER THAN WHITE WHICH IS HOTTER
THAN YELLOW.

VEGA IS WELL OVER 16,800 DEGREES FAHRENHEIT
ON ITS SURFACE.

MUCH HOTTER THAN OUR 10,000 DEGREE YELLOW
SUN.

JAMES:
THE SECOND BRIGHTEST STAR IN THE TRIANGLE,

AND THE ONE OFF TO THE RIGHT, IS CALLED ALTAIR.

ALTAIR IS STARK WHITE
IN COLOR WITH A TEMPERATURE OF 13,400 DEGREE

FAHRENHEIT.

DEAN:
AND THE FAINTEST OF THE THREE, OVER TO THE

LEFT IS CALLED DENEB.

DENEB IS BLUEISH-WHITE - NOT AS BLUE AS VEGA
BUT HOTTER THAN ALTAIR.

IT SCORCHES SPACE WITH A SURFACE TEMPERATURE
OF ABOUT 14,800 DEGREES.

JAMES:
EACH BRIGHT STAR IN THE SUMMER TRIANGLE IS

PART OF ITS OWN CONSTELLATION.

IF I USE MY IMAGINATION (AND SOME HELP FROM
THE STAR GAZERS GRAPHICS DEPARTMENT),

I CAN JUST MAKE
THEM OUT.

VEGA IS PART OF THE CONSTELLATION LYRA
THE HARP.

THE STARS MAKE A TINY PARALLELOGRAM HANGING
OFF VEGA.

IN SOME PICTURES OF LYRA THERES A BIRD AROUND
THE HARP - SINCE PEOPLE ALSO CALLED THIS A

VULTURE.

DEAN:
ALTAIR IS THE EAGLE EYE OF THE CONSTELLATION

AQUILA THE EAGLE.

IF YOU CANT SEE AN EAGLE IN THOSE STARS, YOU'RE
NOT ALONE.

BUT AT LEAST YOU KNOW WHERE THE EYE IS.

JAMES:
AND DENEB IS THE TAIL STAR OF THE STELLAR

SWAN - THE CONSTELLATION CYGNUS.

OKAY, THAT'S AN EASY ONE TO PICTURE WITH
HIS BODY AND LONG, STRETCHED-OUT BEAK.

CYGNUS FORMS A CROSS SHAPE AND IS ALSO CALLED
THE NORTHERN CROSS.

DEAN:
NOW LETS TALK DISTANCES.

VEGA IS THE BRIGHTEST OF THE THREE STARS BUT
IS NOT THE CLOSEST.

THAT HONOR GOES TO ALTAIR WHO IS ONLY
17 LIGHT YEARS AWAY FROM US.

WITH PROFESSIONAL TELESCOPES WE CAN ACTUALLY
SEE THAT ALTAIR IS SPINNING RAPIDLY.

IT SPINS SO FAST THAT IT HAS SQUISHED ITS
SHAPE TO RESEMBLE A BLUE-WHITE EGG.

JAMES:
VEGA IS THE SECOND CLOSEST AT ABOUT

25 LIGHT YEARS AWAY.

THAT MEANS THE LIGHT THAT YOU SEE LEFT VEGA
25 YEARS AGO.

THAT WAS BACK WHEN I HAD HAIR!

DEAN:
HA!

DENEB IS NOT ONLY THE FARTHEST OF THE THREE,
IT IS PERHAPS THE FARTHEST STAR YOU CAN SEE

WITH THE NAKED EYE.

AT A WHOPPING 3000 LIGHT YEARS AWAY,
WE CAN STILL SEE IT AS A BRIGHT STAR.

THAT MEANS DENEB MUST BE HUMONGOUS.

HERE IS A SIDE-BY-SIDE COMPARISON OF THE THREE
SUMMER TRIANGLE STARS

JAMES:
WOW-SERS!

DENEB DWARFS THE OTHER TWO.

DEAN:
SO GET OUTSIDE UNDER THE SUMMER STARS THIS

WEEK.

JAMES:
ENJOY THE WARM SUMMER NIGHTS AND LOOK FOR

THE SUMMER TRIANGLE RISING IN THE EAST.

DEAN:
VEGA, ALTAIR AND DENEB SHINE IN THE SKY

AS SUMMER BEGINS.

SO DEFINITELY

BOTH: KEEP LOOKING UP!