The Delta Aquariid meteor shower has a broad maximum and produces meteors throughout late July and early August. It overlaps with the more famous Perseid meteor shower, which peaks this year on the mornings of August 12 and 13. The Delta Aquariid shower takes its name from the star Skat – also known by its Greek name Delta Aquarii. If you trace the paths of the meteors backward, you’ll find that all Delta Aquariids appear to originate from a point near this star. This point – near Skat – is called the radiant point of the Delta Aquariid meteor shower.
Skat isn’t a bright star. It ranks as only the third-brightest in the dim constellation Aquarius the Water Bearer. Still, you can glimpse this constellation and this star, if you go someplace nice and dark. If you’re in the Northern Hemisphere, you’ll also need a good view to the south. From mid-latitudes in the Southern Hemisphere, the star and constellation are northward and higher in the sky.
If you can see the Great Square of Pegasus and Fomalhaut, they can help you find Skat. See the chart below.
Of course, in actuality, the Delta Aquariid meteors have nothing whatever to do with the star Skat. The meteors burn up some 60 miles (100 km) above Earth’s surface. Skat lies about 160 light-years away.
A meteor shower results when the Earth passes through the orbital path of a comet, and the debris from this passing comet vaporizes in the Earth’s upper atmosphere. The meteors enter Earth’s atmosphere on parallel paths.
Seeing them come from a radiant point in the sky is much the same illusion as standing on railroad tracks and seeing the tracks converge in the distance.
In late July and early August, when the Delta Aquariid meteors are flying, Skat and its constellation Aquarius rise above the horizon in the hours between midnight and dawn. They’re best seen in the evening sky in the months of October, November and December.
No matter when you look, you’ll always find Skat to the south (or below) the Great Square of Pegasus and to the north (or above) the bright star Fomalhaut.
Bottom line: How to find the star Skat, or Delta Aquarii, third-brightest star in the constellation Aquarius the Water Bearer, radiant point for the Delta Aquariid meteor shower. Plus an explanation of why meteors in annual showers have radiant points.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.