Particulars:
General:
A small but bright northern constellation lying between DECL=+30 and DECL=+40 and RA=18h and RA=19h. The fifth-brightest star of the sky, alpha Lyr, called Vega (arabic for "stone eagle"), radiates from the top Lyra with a pure white colour. Together with alpha Cyg, Deneb , and alpha Aql, Atair, Vega forms the Summer Triangle.
Stars and other objects
Beta Lyr is a half separated (i.e. one of the stars reached its
Rochevolume) eclipsing binary of a cream-white colour.
The brightness varies from 3.4 mag to 4.3 mag every twelve days and 22 hours.
With larger telescopes beta Lyr is resolved as an attractive double star
with an blue companion of 8th mag. Additionally two other 9th mag companions
can be seen in small telescopes).
Another double variable is delta Lyr. With the help of binoculars you
can view a blue-white star of 6th mag and a semi-regular red giant. The
brightness of the latter varies erratically from 4th to 5th magnitude.
An easy object with binoculars or small telescopes is zeta Lyr
consisting of a 4th and a 6th mag star.
One of the most celebrated quadruple stars in the sky is epsilon Lyr. It
is commonly known as the Double Double. In a very clear, moonless
night it is possible to see the wide pair of 5th mag stars. Each star of this
double is an double itself. But to resolve them a telescope with at least 60 mm
aperture and a high magnification is needed.
The binary a 11871 requires telescopes with an aperture of at least 12cm
for resolution. The two stars orbit each other with a period of 62 years.
The famous Ring Nebula, M
57, is perhaps somewhat disappointing when viewed through amateur
telescopes but really terrific on long-exposure photographs. In small telescopes
it presents itself on dark nights as a ghostly elliptical disk. Its apparent
size is larger than that of Jupiter. To see the central hole a telescope of at
least 150 mm aperture is needed. The central, very blue star is so faint that
it is beyond the power of amateur telescopes to be revealed. The nebula can be
found half way between beta Lyr and gamma Lyr.
Three meteor showers seem to radiate from this constellation: the
Lyrids, the
June Lyrids and the
Alpha Lyrids. The latter
two are active in the summer time. The Alpha Lyrids are visible from
july, 9th, to july, 20th, and reach their maximum activity on the 14th of july.
As the name suggests the June Lyrids can be observed in june, from the
10th to the 21st reaching the maximum on the 15th with an hourly rate of about
8 meteors. The Lyrids are typically
visible from April, 16th, to April 25th, with its maximum around the 20th to
21st. Detailed information can be found in Gary Kronk's
database about meteor showers.
Mythological Background:
Lyra is thought to represent the harp of Orpheus.
On older skymaps Lyra ist represented as a bird: Vultur, the Vulture. Together
with the Cygnus, the Swan, and Aquila, the Eagle, it is hunted by Hercules.
Another story says that Mercury invented the lyre by placing strings across the
back of a tortoise shell. So sometimes in early descriptions this constellation
is also drawn as a tortoise.