August is the best month to observe the treasures of Lyra, one of the smallest constellations with an area of 286 sq degrees. In our northern sky near the horizon, the constellation can be easily located once you find the bright blue-white multiple star Vega, (α) Alpha Lyrae . Vega is the 5th brightest star in the sky, at magnitude 0.03, 27 ly away. The faint companion stars are not physically connected to the star. A small 10 mag. bluish companion 1’ distant should be visible with a 6 inch telescope. I could not split this with my 5 inch.
In a dark sky the distinct parallelogram of Beta, Gamma, Zeta and Delta, all between magnitude 3 and 4.5 form the shape of the harp.
In Greek mythology the Lyre was made by Hermes, from a tortoise shell with animal gut strings for Apollo who gave it to his son Orpheus. The names of Beta and Gamma Lyrae, Sheliak and Sulafat are from the Persian and Arabic words for harp and tortoise. Vega is from the Arabic phrase representing “Plunging Eagle”. The ancient Arabs saw Alpha, Epsilon and Zeta Lyrae as an Eagle with wings outstretched. Medieval charts depict the constellation as an eagle bearing a harp or lyre in its beak or talons.
Beta Lyrae (β), Sheliak, “the harp” is a multiple star. Resolved to a double in small scopes are a blue mag. 7.2 star and a brighter cream eclipsing binary varying between magnitude 3. 3 and 4.4 in 12.9 days. Using binoculars observe Beta over a couple of weeks using mag.3.2 Gamma Lyr as and aid to detect the changes in its brightness. For a few days Beta and Gamma will appear equal in brightness, then Beta will fade to near half the brightness of Gamma in 13 days. A second minimum occurs 6 days later when Beta is 65% as bright as Gamma.
Gamma Lyr (γ), Sulafat “the tortoise”, mag. 3.2.
Delta (δ) is an unrelated binocular double 10.5’ apart. A spectacular pair. Delta-one is a 5.6 mag blue white star, 1080 ly away. Delta-two (d 2) a 4.2 mag. red giant, 899 ly away appears a brilliant reddish orange with 7 x 50 binoculars. Easily located at the north eastern corner of the lyre.
Epsilon is a rare quadruple star 161 ly away. Also known as the “Double Double”. ε1 mag 4.7 and ε2 mag 4.6, 208” to the northwest can be split easily with binoculars and in a dark sky possibly with the naked eye. A 5 inch scope should show their pairs at high magnification. Using my 5 inch at 122x magnification using a 17 mm eyepiece and 2x Barlow I couldn’t split them into the companion stars. At 172 x with a 12 mm and 2x Barlow ε1 and ε2 had a bulging appearance suggestive of a double, however I could not split them. Seeing was not optimal on the night. The magnitudes of the ε1 pair are mag 5.0 & 6.1 and ε2 mag 5.2 & 5.5 (closer together). The components of ε1 and ε2 are aligned perpendicular to each other, see insert on map.
R Lyrae is a red-orange variable approximately 7°north of Delta Lyrae, varying from 3.9 to 5.0 mag. over 6 – 7 weeks. Suitable for observation with binoculars or a small telescope. At low magnification of 86 x with the 5 inch it has a orange/red appearance. Not as bright or red as Delta -2. I estimated the magnitude between 4.5 and 5.
The gem of Lyra is The Ring Nebula M57 (NGC 6720) mag. 9.3, 2200 ly distant. Also called the “doughnut” or “smoke ring”, the Bright pale blue elliptical ring is a shell of luminous gas formed by a small very hot central star approximately 20,000 years ago. The central star of magnitude 15 is only visible in large aperture telescopes 12 – 14 “ under ideal seeing conditions…I will expect feedback from those with larger scopes than mine…can you see the central star? In my 5” refractor no central or near stars were visible. At 86 x with my 12 mm it appears as a pale green hazy oval doughnut with a dark central region. Averted vision makes these faint planetary nebulae stand out better in the eyepiece.
One magnitude 8 Globular Cluster – M56, NGC 6779 is located on the north eastern border of the constellation 31,000ly away. Follow a line between Gamma Lyrae and Beta Cygni to located M56 just over half way to Beta Cygni. In my 5” at 172 x the cluster appears as a small irregular hazy unresolved cluster of stars. There is an appears of wispy arms spiralling off the cluster, unlike most dense circular globulars. 8 – 10” should resolve stars in the periphery, 12-14” will resolve the cluster. Several observers have described a dark rather than condensed centre at higher power.
The Open Cluster NGC 6791 can be observed with binoculars.
More stars were resolved at high power making field much richer.
For those with 16 to 18 inch telescopes there are a multitude of faint galaxies to track down. NGC 6646, 6671, 6675, 6685, 6688, 6695, and 6702, 6703 which may also be seen with 8 or 10 inch scopes.
Sources: The Night Sky Observers Guide, Vol.2 G.R. Kepple & G.W Sanner, 2000; Burnham’s Celestial Handbook, Volume 2, 1966/1978; Collins Stars and Planets, Ridpath & Tirion 3rdEd 2000; The Messier Objects, SJ O’Meara, 2000; Star Atlas Pro Version 6.2; Photos from Digital Sky Survey www.ngcic.org/dss.