Featured Constellation

Name:
Common Name:
Origin:	One of 48 original constellations introduced by Greek Astronomer Ptolemy - 'The Almagest', circa 140 AD.
Location:	It is one of the most recognizable constellations of the northern hemisphere's summer and autumn; it features a prominent asterism known as the Northern Cross (in contrast to the Southern Cross). It is bordered by the constellations: Cepheus Draco Lyra Vulpecula Pegasus Lacerta It has a size of 804 square degrees which makes it the 16th largest constellation Visible at latitudes between +90° and -40°. Best visible at 21:00 (9 p.m.) during the month of September.

Constellation Figure

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	History:	Phaethon was the son of Clymene, whose husband was the Egyptian King Merops. One day Phaethon's mother told him that Merops was not his father, that his real father was the Sun-god Apollo. When Phaethon boasted to his fiends that his real father was a powerful god, his friends teased him and said that he was not telling that truth. Hurt, Phaethon questioned his mother, who told him: "Go to the Sun-god and ask him yourself if you doubt my word." The Sun-god was delighted to see his son and promised Phaethon anything he requested in the way of proving to his friends that Apollo was his father. Phaethon thought for a while and finally said that he wanted permission to drive the Sun-chariot across the sky for one day. Apollo was shocked and tried to convince his son that it was a very dangerous thing to do and the boy would reconsider his request. Phaethon refused to change his mind, so there was nothing for Apollo to do but keep his word. Phaethon was inexperienced in driving a chariot and it did not take the horses long to realize that an unsure hand was on the reins. First they bolted high up in the sky, far higher than they usually did, in their eagerness to rise above the eastern horizon and reach the top of the great sky dome. It was here that they scorched a great streak across the sky, a streak that became the Milky Way. Meanwhile, Earth's surface became cold because the Sun-chariot was too high in the sky. Next the horses plunged to close to Earth. As they crossed Africa they scorched the ground, creating a great desert and drying up rivers, lakes, and watering holes. Horrified, Phaethon saw ahead a great scorpion (Scorpius) in the sky. Its mighty tail flashed and stung the lead horse. Up went the chariot again, even more wildly than before. Poor Phaethon now realized his foolishness that he should have listened to his father's warning. Zeus, King of the Gods, decided that it was time to stop this rash youth from causing more destruction. He hurled a thunderbolt at Phaethon, killing the boy instantly and sending his smoldering body tumbling down to Earth. The horses returned to their stable and Phaethon's body eventually fell into the Eridanus River and sank to the bottom. Phaethon had a very devoted friend, Cycnus, the Musician-king of the Ligurians. On hearing of Phaeton's fate, Cycnus plunged into the Eridanus and swam back and forth, diving repeatedly to try to find the body of his friend. His motions through the water made him look like a swan searching for food. Apollo took pity on Cycnus, who died of grief, and raised him to stardom, where he became the constellation Cygnus the Swan.

	Features:	Several star clusters and nebulae are found in Cygnus due to its position on the Milky Way. The North America Nebula (NGC 7000) is found a bit to the east of Deneb. Its resemblance to the continent is best appreciated in photographs. The Pelican Nebula (IC 5070) is nearby. To the south of Epsilon Cygni is the Veil Nebula (NGC 6960, 6962, 6979, 6992, and 6995) which is an ancient supernova remnant covering approximately 3 degrees of the sky. Also of note is the Crescent Nebula (NGC 6888), located between Gamma and Eta Cygni, which was formed by the Wolf-Rayet star HD 192163. More supernovae have been seen in the Fireworks Galaxy (NGC 6946) than in any other galaxy. The constellation also contains the X-ray source Cygnus X-1, which is now known to be caused by a black hole accreting matter in a binary star system. The system is located close to the star Eta Cygni on star charts.

N. American Nebula (NGC 7000)

Cocoon Nebula (IC 5146)

Crescent Nebula (NGC 6888)

Veil (West) Nebula (NGC 6960)

NGC 7000 so named because of its resemblance to the North American Continent is a large emission nebula; angular size 120' x 100'; magnitude 5; distance 1800 l.y.; discovered 1786 by William Herschel.

IC 5146 - Cocoon Nebula is an Emission Nebula situated inside a 'Pool' of the dark nebula B168; angular size 10'; distance of 3300 l.y.; discovered photographically in 1894 by Max Wolf.

NGC 6888 is a bright Emission Nebula in the shape of a Crescent; magnitude 8.8' angular size 18' x 13'; lying at a distance of 4700 light years; discovered by William Herschel in 1792.

NGC 6960 - 'Witch's Broom' is part of the Cygnus Loop, a large relatively faint supernova remnant; angular size 70' x 6'; distance 2000 light years; discovered by William Herschel in 1784.

Brightest Stars

Notes

Name	Mag.	Spectra	Common Name
50 Alpha Cyg.	1.25	A2Ia	Deneb
37 Gamma Cyg.	2.20	F8Ib	Sadr
53 Epsilon Cyg.	2.46	K0-III	Gienah Cygni
18 Delta Cyg.	2.87	B9.5IV+F1V
6 Beta1 Cyg.	3.08	K3II+B9.5V	Albiero
64 Zeta Cyg.	3.20	G8+III-IIIaBa0.6
65 Tau Cyg.	3.72	F2IV
62 Xi Cyg.	3.72	K4.5Ib-II
1 Kappa Cyg.	3.77	G9III
31 Cyg.	3.79	K2II+B3V

The Star Names are taken directly from the Bright Star Catalogue and incorporates the Bayer (Greek Letter) and Flamsteed (Numerical) notation, together with the IAU abbreviation of the Constellation Name. 
                                            
The Stellar Spectra listed above are based on the Morgan-Keenan system, in which each star is allocated a letter - O, B, A, F, G, K and M; where O is the hottest and M the coolest. Traditionally, O stars are ‘blue’; A stars ‘white’; G stars ‘yellow’, K ‘orange’ and M stars are ‘red’. 
                                            
In the ‘Morgan-Keenan’  system the letter is further enhanced by a number from 0 to 9,indicating tenths between two neighbouring classes. 
                                            
A further sub-division is introduced in which the Roman Numerals I, II, II, IV and V are used to indicate the width of certain absorption lines in a star’s spectra, which in turn are a measure of the star’s size. Type I are called ‘supergiant’ stars, Type III are ‘giants’ and Type V ‘dwarf’ or main sequence stars. 

For example our sun has a spectra of type G2V, which means it is a yellow dwarf star nearer to a type F star than a K type star. The brightest star in the heavens Sirius is classed as type A1V.



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