Expert: Tom Whiting - 10/7/2008

Question
QUESTION: do you know the full name of the constellation draco?

ANSWER: Hi Caro,

That is it's full name, precisely Draco, the dragon (in old days
when men pictured animals and men).
Today, and since 1930 when the IAU (International Astronomical
Union) determined set boundaries of areas called constellations, it's now just an area of the sky, just like California or Arizona,
and HAS been for the past 78 years!

IN fact, constellations are easier to learn then the states of
the USA, because all the boundary lines run either North-South,
or East-west. There are no diagonal lines like the Nevada/California
border, or highly irregular lines like the Mississippi river
divisions. And there are only about 40 Northern Hemisphere
constellations (areas) so there are less than the 50 states of the
USA!!  Basically, I just picture a rectangle or square around
the different star patterns (the stars are the "cities" in the state)
and that's close enough. Oh, and the lines we draw connecting the
star patterns in that 'area' are simply the interstate highways
connecting the 'cities' or stars if you wish.
It's not rocket science, it's that simple. So, thank goodness, no need to picture an animal or man or harp or sextant or scorpion or....dragon.  Those days are long gone!
They are just simple....pretty much rectangular areas and that's close enough for me.  Of course, you have to mentally 'picture'
about where those lines are, but isn't it the same when you cross a
state line? There's no actual line there, just a road sign telling you that you are now in a different state. We don't have the road signs telling us, you just have to imagine those lines yourself.
That's the only difference.
Hope this helps,
Clear Skies,
Tom Whiting
Erie, PA


















---------- FOLLOW-UP ----------

QUESTION: thanks so much now i was also wondering does draco have 14 or 15 stars? and
do u know any of their names

Answer
Hi again Caro,
Well, the number of major stars in Draco depends on what you consider
your limiting magnitude. My Olcott's Field Book of the skies plots
19 stars, 5th magnitude or brighter. But on a more detailed page,
(showing the majority of the nice double stars) Olcott's plots
nearly 40 stars. My Cambridge 2000.0 Star Atlas plots hundreds of
stars in Draco of magnitude 6.4 and brighter, and of course my
Uranometria (good down to 9.5 magnitude for binoculars and telescopes) plots thousands of stars in Draco, as it does for any other constellation.
Well, typically the major stars are designated by a lower case
Greek letter (like ALL constellations) where typically the Alpha
star is the brightest (or most famous), then
Beta, Gamma, Delta, Epsilon, and so on down to the last Greek letter
Omega...followed by the latin genitive case (possessive case in
English), of the constellation name.
Thus we have stars Alpha Draconis, Beta Draconis, Gamma Draconis,
Delta, Epsilon, etc etc. all the way to Omega Draconis. Draco is
so large and prolific, that I believe all 24 Greek letters are used. Then we go to Flamsteed numbers, for instance the very pretty double stars 40 and 41 Draconis, while 17 Draconis and 39 Draconis are fine multiple stars at magnitude 5.5 and 5.0 respectively.  This is the
standard way that ALL constellations are done, arranged, and classified.
As far as "common names" most of us don't memorize those unless it
is a very bright star (like Vega, Deneb, Antares) or very famous
but not so bright, like Polaris, Algol,... and Thuban, which is also the star Alpha Draconis.
Thuban is famous because it was the North Pole star during when the Pyramids of Egypt were being constructed some
4000 years ago...that's why it's so famous, and thus has a common
name too.  That's why Thuban is the Alpha star even though it's not
the brightest...the bright 2nd magnitude star in the 'head' of
Draco is Gamma Draconis, is the brightest star in the whole constellation -Area. But the prettiest star in the head is the
famous equal magnitude (5.0) double snake eye star, Nu Draconis.
AT a separation of 62 arc-seconds, Nu can be split by steadily held
binoculars, a field glass double. Very Fine. Nu is the dimmest
naked eye primary star in the head of Draco.
(And realize when we say the 'head of Draco' we still are not picturing a Dragon; it's like saying the Panhandle of Texas or the
upper peninula of Michigan - It narrows down the area of sky we are
discussing, so you don't have to look all over the entire constellation for the specific part or area we are talking about!)

There are also many fine deep sky objects hiding out in Draco for
your telescope, the most famous is NGC 6543 or the Cat Eye Nebula,
a few degrees from star Zeta Draconis.
(Google it for some fine Hubble pictures of same). There is also
a beautiful red carbon star, UX Draconis located there. There is also
some fine, but faint telescopic galaxies in Draco.

One problem with Draco, being so close to the pole, it's tough to
put an area 'box' around it, as it begins as the tail (line of stars) between the two dippers, wraps up and over the Little Dipper (Ursa Minor) then dives due south toward the bright star Vega, where
the 'head' is located.  So you almost have to enshroud Draco in a 'tube' or cylinder area. It's one of the few constellations that does not lend itself to an easy rectangular shape like most others. Fortunately, there aren't too many constellations like that, but Draco is a little tougher than most, in that respect. (You started with a tough one.)

So in summation, yes....all the names in Draco run from Alpha to
Omega Draconis (the first and last Greek letters, and all 22 inbetween).
Remember, these are lower case, not upper case letters as in Fraternities or Sororities in colleges. Us astronomers know all the lower case Greek Letters, but none of the upper case. (Joke, of course).  And yes, I know all of their names, just like I know the
names of major cities in my home state of Pennsylvania....it's all the same to me. And I especially know where the deep sky objects are
because that's what I want to see with my telescope.
Hope this helps,
Clear Skies,
Tom Whiting
Erie, PA

PS...Why the 'obsession' with Draco?? It's just one of 40 area's
of the sky in the N. Hemsphere.