Best viewed in June through October, Eta Lyrae is a variable and binary star in the constellation Lyra. The traditional name for the star is Aladfar, Arabic for the talons of a swooping eagle. At a magnitude of 4.5, one should be able to spot the star from a dark sky location with the naked eye.
Aladfar’s dimmer appearance masks its true brilliance in the galaxy. It’s a massive hot blue-white star with a diameter 11 times larger than the sun and a total luminosity, or energy output, of 21,000 times that of the sun! Wow. I’m glad these “talons,” with their obliterating power, lie 1,300 light-years safely away from us.
Aladfar’s notable secondary star lies 28″ (arcseconds) away. With this distance, backyard astronomers with smaller telescopes should be able to enjoy this binary.
My Observations
| Date | July 30, 2022 |
| Time | 11:25 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Good |
| Transparency | Good |
This evening has been so productive and enjoyable. Aladfar lies outside the main structure of the harp on the side near Cygnus. The primary star is a brilliant blue-white color. The secondary star appears to be a darker yellow, or maybe it even falls into the orange range. However, as I write this, I’ve read several observations that the star is actually a light blue. In addition, several faint stars are floating around this binary, and two pairs of stars are nearby. These may be a part of its multiple-star system, I assume.
Key Stats
| Constellation | Lrya |
| Best Viewing | Summer/Autumn |
| Visual Magnitude | +4.4, +8.6 |
| Absolute Visual Magnitude | -6.09 |
| Distance from Earth | 1,300 ly |
| Separation | 28.4 ″ | 12,000 AU |
| Position Angle | 81° |
| Milky Way Location | Orion Spur |
| My Viewing Grade | B |
| Designations | Struve 2487, STF 2587, SAO68010, η Lyrae, 20 Lyrae, HD180163, Σ 2487 |
Sources and Notes
Banner shared under the Creative Commons Attribution-Share Alike 4.0 International license. Photo by David Ritter. Details here.
1 “Eta Lyrae.” Wikipedia, Wikimedia Foundation, 27 Mar. 2022, https://en.wikipedia.org/wiki/Eta_Lyrae.
2 Aladfar, http://stars.astro.illinois.edu/sow/aladfar.html.
Sketch by Wayne McGraw
The Garden Astronomer 
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