April 22
Lyrid Night
Sun Position
The Sun is in Taurus near +21° declination. Northern hemisphere evenings are long and the sky does not fully darken until after 9 PM at mid-latitudes; southern hemisphere offers excellent dark skies from mid-evening.
Sky Highlight
The Lyrids peak around April 22, with typical rates of 18 to 20 meteors per hour under dark skies, occasionally surging to outburst rates above 100 in some years. The debris comes from Comet C/1861 G1 Thatcher, and Lyrids have been recorded in Chinese astronomical records as far back as 687 BCE. The radiant near Vega is highest in the pre-dawn hours; northern hemisphere observers have the better geometry.
Deep Sky Object
M57, the Ring Nebula (NGC 6720), planetary nebula in Lyra, about 2,300 light-years. M57 is the most observed planetary nebula in the sky, a near-perfect smoke ring of ionized gas around a dying white dwarf; it is visible as a distinct elliptical disk in a small telescope and resolves into its ring structure with 6 inches of aperture. Visible from both hemispheres.
Featured Star
Izar (ε Boo) is a striking double at 203 light-years: a K0II orange giant paired with a much hotter A2V white companion separated by about 3 arcseconds. William Herschel called it Pulcherrima ('most beautiful') for the color contrast between the warm orange primary and the blue-white secondary; splitting it requires about 75mm of aperture.
Around This Date
- April 22, 687 BCEChinese astronomical records contain what is believed to be the earliest written description of the Lyrid meteor shower, noting a rain of stars visible before dawn, observations consistent with the Lyrids radiant in Lyra.
- April 22, 2010The U.S. Air Force launched the X-37B Orbital Test Vehicle on its first flight, beginning a series of long-duration robotic spaceplane missions whose payloads and objectives remained classified.
Lyrids have been falling on this date for at least 2,700 years of human record-keeping; Comet Thatcher is still out there, leaving the trail.