Lyra Constellation: Home of Vega and the Ring Nebula

Lyra is one of the smallest constellations in the sky, but what it lacks in size it more than makes up for in quality. Its alpha star, Vega, is the fifth brightest star visible from Earth and one of the most studied stars in all of astronomy. Tucked between its fainter stars lies the Ring Nebula (M57), a perfect little smoke ring that's one of the most observed planetary nebulae in the sky. And for telescope owners, the double-double star Epsilon Lyrae is one of the finest optical tests you can perform.

Finding Lyra

Finding Lyra is as easy as finding Vega, and finding Vega is as easy as looking up on a summer evening. Vega is one of the three stars that form the Summer Triangle, the dominant asterism of the summer sky in the Northern Hemisphere, along with Deneb (in Cygnus) and Altair (in Aquila).

From mid-northern latitudes, Vega is nearly overhead in July and August. It's blindingly bright at magnitude +0.03 and has a distinctive blue-white color. Once you've found Vega, the rest of Lyra is a small parallelogram of fainter stars hanging just below it.

Vega: The Standard Star

Vega has played a unique role in the history of astronomy. It was the first star (other than the Sun) to be photographed, in 1850. It was the first star to have its spectrum recorded. And for decades, it served as the zero-point calibration star for the magnitude system, magnitude 0.00 was defined as "the brightness of Vega." (Modern calibrations have shifted slightly, so Vega is now +0.03, but the principle remains.)

Vega is a main-sequence A0 star, about 25 light-years from Earth. It's roughly twice the mass of the Sun, about 40 times more luminous, and spinning so fast that it's noticeably oblate, wider at the equator than at the poles. Its surface temperature is about 9,600 K, giving it that striking blue-white color.

In the 1980s, the IRAS infrared satellite discovered a disk of dust around Vega, one of the first debris disks found around another star, hinting at a possible planetary system. The search for planets around Vega continues.

The Ring Nebula (M57)

Between the two bottom stars of Lyra's parallelogram (Beta and Gamma Lyrae) lies the Ring Nebula, catalogued as Messier 57. This is a planetary nebula, the expelled outer layers of a dying Sun-like star, illuminated by the hot white dwarf left behind at the center.

M57 is small (about 1.4 x 1.0 arcminutes) but bright enough to spot in a 4-inch telescope at 80-100x magnification. It appears as a tiny, slightly elongated ring, a ghostly smoke ring floating in the star field. The donut shape is unmistakable once you know what to look for.

In an 8-inch or larger telescope, you may notice that the ring isn't uniform, the edges are slightly brighter on the ends of the long axis. Through a 12-inch+ under excellent seeing, the central star (magnitude +15) becomes visible. Detecting it is a satisfying observing challenge. For more on planetary nebulae, see our guide to the Cat's Eye Nebula.

Epsilon Lyrae: The Double-Double

Near Vega lies Epsilon Lyrae, one of the most famous multiple star systems in the sky. To the naked eye or binoculars, it appears as two stars close together. But point a telescope at 150x or higher, and each of those two stars splits into a pair, giving you four stars total. It's a genuine quadruple star system.

Splitting the wide pair is easy in binoculars. Splitting each pair into its components requires steady seeing and at least a 3-4 inch telescope at 150x magnification. It's a classic test of both your telescope's optics and the atmospheric conditions. On a night when you can cleanly split all four components, you know the seeing is excellent.

Other Targets in Lyra

• Beta Lyrae (Sheliak): An eclipsing binary star whose brightness varies between magnitude +3.3 and +4.4 over a 12.9-day cycle. You can track its brightness changes with just your naked eye by comparing it to neighboring stars.
• M56: A globular cluster about halfway between Lyra and Cygnus. It's small and fairly compact at magnitude +8.3, but resolves into individual stars in an 8-inch telescope.
• NGC 6791: One of the oldest and most metal-rich open clusters known. Faint but scientifically fascinating, a stellar retirement home containing stars up to 8 billion years old.

Best Time to Observe

Lyra is a summer constellation, best observed from June through September. Vega is already high in the sky at dusk during July and doesn't set until well after midnight. From northern latitudes, Vega is circumpolar, meaning it never fully sets, but it's at its best when nearly overhead on summer evenings.

If you're planning a summer observing session, start with the tonight's sky guide to see what else is well-placed alongside Lyra.