There are three different Capricornids meteor showers that occur each year in the spring and again in the summer. From April 19th to May 15th, we experience the Omega Capricornids. In July we begin to experience two other Capricornids showers with the Alpha Capricornids occurring from July 15th through September 11th, and the Sigma Capricornids occurring from July 15th through August 11th.
Of these three Capricornids showers, the most popular is the Alpha shower. This annual meteor shower was officially discovered in 1871 by an astronomer in Hungary named Miklós von Konkoly Thege. He was the first astronomer to chart several meteors emanating from the same constellation, Alpha Capricorni, on two consecutive nights. By the last part of the 19th century, his observations were confirmed by other astronomers that noted the same results, determining that the Alpha Capricornids were a consistent and annual meteor shower.
The Alpha Capricornids are not known for being a strong shower, as even during their peak dates of July 31st and August 1st they only produce a maximum rate of around ten meteorites per hour. The best time to view the Capricornids is between midnight and early dawn, and the shower is most easily viewed from the southern hemisphere. The Capricornids may not produce a large number of meteors, but one thing the Alpha Capricornids are known for are their bright yellow meteorites that create beautiful fiery streaks across the sky. What the Capricornids lack in quantity, they certainly make up for in quality.
Astronomers have yet to determine the source of the Capricornids. There has been much speculation in recent years that various comets and at least one asteroid were once the source, but further evaluation has proven that none of these sources fits the correct orbit of the debris stream that results in the meteor shower that we see.
Christopher L. Shelby, M.D.