PROJECT: Constellation Draco

Draco- the Guard of stars
"... Every night the fabulously jewelers made of sky brilliants - the stars- flicker above people's heads. They have decorated the night sky for thousands of years and none of them disappeared. Why? Because god Marduk put on the sky an eternally awaken dragon, who guards them…"

1. Introduction...
Dragon is a constellation built up from not very bright stars that is found between both bears. It is always above the horizon - it doesn't rise or fall- always on guard, near to the North pole. Although it has a huge size, this constellation is not very often observed, maybe because there aren't bright galaxies or nebulae in its dimensions. But the stars in it are so beautiful and interesting!

2.Historical information
In the past...
The constellation Draco is one of the oldest
constellations. Draco exists in legends and
myths of many nations. The oldest legend about
Draco comes from the Sumerians and
Babylonians of the Tigris and Euphrates Valley
more than 5,000 years ago. These people
spoke of a female dragon they called Tiamat
that existed at the beginning of creation, before
earth and sky were separated. Tiamat ruled
over the wild, chaotic and evil primordial ocean,
but eventually newer gods arose and rebelled
against her. Thus, Marduk challenged Tiamat with strength and cleverness. He caused violent winds to blow right into the gaping dragon's mouth, tearing her asunder. Then Marduk cleaved her skull and cut her skin into two parts from which he formed heaven and earth. This original great dragon slayer put the stars in their courses and ordered the seasons. He fixed the sky with an axis bolted to one star within the constellation that eventually became known as Draco, the Dragon.
This epic story is portrayed by the fact that in
those early Chaldean times the pole star was
the one we know as Thuban, a star in the body
of Draco. At that time the entire heavens
revolved about Thuban, as it does today about
the Polaris, our current North Star Fig3
located in the constellation Ursa Minor. In those
glorious Mediterranean times Thuban was a
most important star as evidenced by the fact that
the Great Pyramid of Khufu at Giza contains a
300-foot long shaft running from the heart of the pyramid to a small opening that looked directly at Thuban, the point about which the heavens turned when the Pyramid was constructed.
Khufu's burial chamber was fashioned deep inside the Great Pyramid. Two skinny shafts bore outward from the chamber. For decades, scholars thought they were airshafts. But in the 1960s, astronomers found that they have an astronomical purpose.
At the time the pyramid was built, one of the shafts aimed toward the star that was then closest to the north celestial pole. The other aimed at the belt of Orion, one of the brightest and most impressive constellations.
The north celestial pole is the "hub" of the northern sky. All the stars appear to rotate around this hub.
Today, the star Polaris marks the north pole. But Earth wobbles on its axis. It takes about 26,000 years to make one full wobble, and in that time, the north pole points to different stars. When the pyramids were built, the star closest to the pole was Thuban, in Draco, the dragon. The stars close to the pole never set. The Egyptians described these stars as "imperishable" or "undying." Khufu expected that when he died, he would join not only with the Sun, but with Thuban as well ‹ maintaining order in the celestial realm, just as he had on Earth.
The Egyptians saw Draco as a hippopotamus or crocodile, representing gods and goddesses who appeared in the forms of those animals.
Greek and Roman mythology have many legends about
dragons and serpents, but two specially are connected
with Draco. One story is Zeus's battle against his father,
the Titan Cronus. It had been prophesied that one of his
own sons would dethrone him, so each time his wife
Rhea bore a child, Cronus swallowed it. Rhea hid the
infant Zeus and tricked Cronus into swallowing a stone.
He uncovered the trick and went after Zeus who escaped
by turning himself into a serpent and his nurses into bears.
The constellations Draco and Ursa Major and Minor
commemorate his escape.
Another legend is the eleventh labor of Hercules. Hercules
was asked to obtain fruit from the golden apple tree, a
wedding gift from Gaia, that was planted in Hera's garden
and guarded by the dragon Ladon. In accomplishing the
task, Hercules killed the dragon. Hera wept for Ladon
and set his image in the stars.
The Persians have regarded Draco as a man-eating
serpent called 'Azhdeha'. In early Hindu worship, Draco
is given the form of an alligator known as 'Shi-shu-mara'.
Draco is a challenge to learn to recognize, being composed of dimmer stars that twist around in snake-like fashion.

3. Nowadays...
Draco shows its treasures...

The constellation Draco is not very easy for observations because it contains dimmer stars that twist around in snake-like fashion. The best time for observation of this constellation is September - then it is well placed standing upright in the north. As it gets dark, start by locating the Great Dipper low to the west of north. Follow the last two stars of the Dipper bowl upward to Polaris at the end of the Little Dipper handle (end of the tail of the Little Bear). The Small Dipper is oriented so that the handle goes from Polaris to the left. Although the handle stars are very dim, the bowl contains two brighter stars, sometimes called "Guardians of the North Star.". The end of Draco's tail is right between the two dippers. The body is formed by a string of tiny stars going up to the left, then bending to the right above the bowl of the Little Dipper. It bends again back to the left where a triangle of stars forms the Dragon's head next to one of the feet of Hercules. The entire figure of Draco forms a more-or-less "S" shape with the end of the tail low in the north and the head high to the west of north. Thuban is the third star from the end of Draco's tail.

Dragon's treasures:

The most interesting star from this constellation is Thuban.
Thuban is the Arabic name for Dragon. Thuban is named after a star. Its full astronomical name is "Alpha Draconis". Thuban, is a mag. 3.7 A type (white). To find Thuban, sweep down the length of the Little Dipper, and jump over to the end of the handle of the Big Dipper. Midway is found a much fainter star, which is Thuban.
It was once thought to be the brightest star in the constellation Draco, hence the 'Alpha' designation. The honor really goes to a star named Eltanin, "Gamma Draco". It is believed that Thuban was considerably brighter several thousand years ago.
Eltanin is a star system of 7 stars. The brightest star Eltanin A is an orange giant from spectral class K5. The name Altnin in Arabic means "the eye of the Dragon", This star is found 100 light years from the Earth and observed from our planet the star is 2m.23
It is a real pleasure to be observed double stars in Dragon. The most beautiful double star is Nu Draconis. It is a splendid fixed binary, found in the dragon's head. Two similar 4.9 visual magnitude stars: PA 312? and separation 61.6". The two white stars (an A6V and an A4m) have magnitudes of 4.88 and 4.87. They are a good object for binoculars.
Mu Draconis is one of the closer binaries, a slow orbit of 482 years. The binary mu Dra is a good test for a scope with an aperture of 60mm. Good optics might split that pair consisting of two F7 main sequence stars (5.83 mag and 5.80 mag).
Epsilon Dra is a good double to be observed with scopes at a moderate magnification. Its companions are about 3 arc sec apart.
Omicron Draconis has a fine colour contrast, orange and blue. Magnitudes 4.7, 7.5; PA 326?, separation 34.2".Small scopes reveal the 8th mag blue companion of the G9IIIbCN-0.5 star omicron Dra (4.66 mag). Omicron Draconis has a fine colour contrast,orange and blue. Magnitudes 4.7, 7.5; PA 326?,separation 34.2".
A good binocular may be sufficient to split the pair of psi Dra. Small scopes show a 5th mag star and a 6th mag star. Another easy pair for small telescopes is 40-41 Dra. The two yellow stars are of 6th mag. Its coordinates are roughly RA=18h and Psi Draconis is also easily resolved: 4.9, 6.1; PA 15?, separation 30.3" DECL=+80 degrees.
17 Draconis forms a magnificent fixed triple with 16 Draconis. 17AB: 5.5, 6.4, PA 108degrees, separation 3.4"; 16 Draconis is component C: PA194, separation 90.3".
26 Draconis is a close binary with orbit of 76 years. The component is currently at PA 334degrees and separation 1.6". There is a faint (10m) very wide third member, at PA 162degrees and separation 12.3'. 41 and 40 Draconis (Struve 2308) form a pleasant, fairly wide, binary of two cream-coloured stars: 5.7, 6.0: PA 232?, 19.3". Note that 41 is the primary. Struve 2398 is an extremely near binary at only 11.3 light years. It consists of two red dwarfs, 8.0, 8.5; PA 163degrees, separation 15.3". It is thought the companion has an orbit of roughly 350 years. The binary is found just between omicron Draconis (which to the east) and 39 Draconis.
A really impressive triple system is 39 Dra. Field glasses show a wide double; in larger scopes a third star close to the brighter one occurs. Another attractive triple is 16-17. In binoculars two blue-white stars of 5th mag are revealed. Viewing with a telescope shows another star of 7th mag close to one of the first two.

Variable stars in Draco:
R Draconis is a Mira-type variable with a period of 245.6 days; it fluctuates from 6.7 to 13.2 magnitude. In 2000 the maximum should occur in the third week of April.

Deep Sky Objects in Draco
Draco offers one Messier object: M102. With several dozen other galaxies, and a
bright planetary nebula, there are plenty of objects to study. Below are a few suggestions.
M102 (NGC 5866) is an edge-on galaxy with dust lane and brightly glowing centre. The galaxy is four degrees southwest of iotaDraconis. NGC 5907 is in the same region one degree east of M102. This is another edge-on (nearly flat) galaxy with dust lane.
NGC 5985 is an inclined spiral, quite faint unless under ideal conditions. NGC 5985 is midway between iota and theta Draconis; (NGC 5982 is in the same field to the west. This elliptical gallaxy is considerably smaller but about the same magnitude, around 12).
NGC 6543 : a planetary nebula that appears as a miniscule blue-green disk. Because of its blue-green colouring, it is sometimes called the Cat's Eye Nebula. It's located halfway between delta and zeta Draconis. It's exact distance isn't known; estimates vary from 1500 to 3500 light years. At a magnitude of 8.8, the planetary nebula NGC 6543 is one of the brightest in the sky. It was the first planetary nebula to be observed with a spectroscope; the observers were surprised to find emission lines in the spectrum of this object. This started the controversy whether planetaries are numerous stars or, as it turned out to be, clouds of diffuse gas. A small telescope (about 70 to 80 mm aperture) shows a foggy blue-green disk; more powerful scopes are required to reveal the internal structure: a bright irregular helix. Since NGC 6543 is a circumpolar object for most observers, you can view it throughout the year. It can be found half way between delta Dra and zeta Dra (RA=18h is closely running through it).
The quasar 3C 351 lies at RA=17h, DECL=+60 deg. It has a brightness of 15.3 mag and shows a redshift of.371 in its spectrum. This yields a distance of about 7 billions (7*10^9) light-years. From October 6th to October 10th the meteor shower of the
Meteor storm Draconids is very active; this shower is associated with the comet Giacobini-Zinner and has a sharply defined maximum on October 9th.

Three Galaxies in Draco
This intriguing trio of galaxies is sometimes called
the NGC 5985/Draco Group and so (quite
reasonably) is located in the constellation Draco.
From left to right are face-on spiral NGC 5985,
elliptical galaxy NGC 5982, and edge-on spiral
NGC 5981 all within this single telescopic field
of view spanning a little more than half the width
of the full moon. While this grouping is far too
small to be a galaxy cluster and has not been
cataloged as a compact group, these galaxies do
lie roughly 100 million light-years from the planet Earth. On close examination with spectrographs, the bright core of the striking face-on spiral NGC 5985 shows prominent emission in specific wavelengths of light, prompting astronomers to classify it as a Seyfert, a type of active galaxy. Not as well known as other tight groupings of galaxies, the contrast in visual appearance makes this triplet an attractive subject for avid astrophotographers.

In the Future...
The Pole Star -- Wichahpi Owanjila, a star that always stands in one place -- was Thuban (Alpha Draconis) around 3000 BC. Around 7500 AD, Alpha Ceiphei will be the pole star, then Deneb, then bright Vega (14000 AD), then it'll swing around to Thuban again. For many centuries there has been and will be no bright star close enough to where the pole is to serve as pole star; the bright northern stars and constellations then seem to revolve through the night about an empty center.

4.Our observations
Visual observations: We observed the stars from the constellation Draco. The most interesting stars were the double stars. We made sketches of 2 double stars Nyu and Ksi from Draco. We made the observations with a binocular 10x50.

Fig.8: The double star Nyu ...................... . Fig.9: The double star Ksi

CCD observations
We observed the star Thuban with CCD
ST8 with 50/70 cm Schmidt telescope in
NAO-Rozhen. The image was taken on
03.08.2002 UT=12h28min17 sec
exp= 5sec V filter



5. Comparison:
We made a comparison with another constellation that is situated around the pole- Ursa Minor. Both constellations are very interesting and important. In them there are many interesting objects that can be observed with small telescopes. We will show the comparison in a table.

Using the facts that the nearest to the north pole star is
the Polar star and that after 12 000 years the Polar star
will be the star Vega from the the constellation Lyra,
draw on the sky map the circumference that the Earth
forms in its turning around its axis for 26 000 years.
Which stars will be polar stars and after how many years?
This exercise has the goal to make students understand
the phenomenon and find( first on the map and then on
the sky) which will be the polar stars after a definite
period of time.
Necessary information: The Earth axis moves slowly
in space. For about 26 000 years it makes a full cone
and then goes back to its first position. This phenomenon is called precession. It is caused by the form of the Earth. The gravitational effect of the Sun and the Moon on our elliptic planet causes changes in the orientation of the Earth axis.

Fig. 13: Pictures necessary for the exercise

Because of the phenomenon procession sky maps become old with the time. The position of the sky poles changes continuously. If now the Polar star is near the North Pole, after 12 000 years the polar star will be the bright star from the constellation Lyra.
Task1: Find the Polar star and Vega on the sky map. Draw a circle with diameter equal to the distance between these stars.
Task2: Divide the circle into 26 parts- each part = 1000 years.
Task3: Mark which stars and from which constellations are on the circumference that is made by the Earth axis.
Task4: Find these stars on the night sky.

The constellation Draco is very interesting and important. The introduction of legends about it, star and nebulae objects connects us with ancient astronomers who observed Thuban and with future astronomers who will have different polar stars. This constellation is very appropriate for explanation of procession and for solving different tasks, connected with it.
We learned many new things about this constellation. It provoked us and Manuela- a member of our team- wrote a fantastic tale about "Draco- the guard of stars".

Fig. 14: The constellation Draco

Draco is a fantastic treasure-house of stars, galaxies and knowledge that comes from antiquity and goes in the future.


Myths and legends for constellations, Angel Bonov
Encyclopedia for children, Moskva, 1999

For Contacts:
Manoela Mikaelian
Anna Iotova
Leader: Veselka Radeva - Astronomical Observatory, Varna, Bulgaria

Special thanks to the National Astronomical Observatory- Rozhen for their help
and to Nadezhda Lyubomirova
for the translation in English and web-design!

Fig.1: The Constellation Draco

Fig.2: The star Thuban in ancient Egypt

Fig. 3:Picture of constellation Draco

Fig.4: Constellation Draco

Fig.5: The stars from the constellation Draco

Fig.6: Planetary nebulae Cat's Eye

Fig. 7: Galaxies in Draco

Fig. 10: The star Thuban from the Constellation Draco

Fig. 12: The Polar star

Fig.11: A sky map
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