The Perseid meteor shower is among the finest annual meteor showers, always reliable, producing a flux of fast and bright meteors. This year's maximum occurs on August 12th at 12 UT, favouring observers in western USA and western Canada. The best time to look is during the early morning hours when the 66% illuminated waxing gibbous Moon will have already set. At peak up to 100 meteors per hour are predicted. In addition, reasonable activity is also expected on the nights of August 11th/12th and August 12th/13th from all Northern Hemisphere locations. Recent analysis by NASA has rated the Perseids as the best meteor shower when it comes to fireballs.
For those at southern locations, the radiant remains close to or never rises above the horizon. This considerably reduces the amount of visible meteors, although it's possible to spot some of them coming up above the northern horizon.
Discovery and Parent Body
The Perseids meteor shower is associated with comet 109P/Swift-Tuttle (Swift-Tuttle), a Halley-type comet with an orbital period of 133 years. It's believed that most of the dust in the meteor cloud today is about 1000 years old, although some parts may be considerably younger. When the Earth passes through a replenished dust area the meteor rate often increases dramatically.
Chinese observers first recorded the Perseids in 36 AD. Lewis Swift discovered comet Swift-Tuttle on July 16, 1862 followed independently by Horace Parnell Tuttle three days later. Computations made by Italian astronomer Giovanni Schiaparelli between 1864 and 1866 revealed a strong resemblance between the meteor stream and the cometary orbit, providing a definite association for the first time.
The radiant is the point in the sky where the meteors appear to originate from. The Perseid radiant is in Perseus at right ascension (RA) 02hr 27m, declination (DEC) +58 degrees, which is close to the famous Double Cluster (NGC 869/NGC 864) and the Cassiopeia constellation border.
What to expect
The meteors are visible from about July 17th to August 24th. Rates start slow but then shoot up from August 8th/9th until the peak date, after which they fall off quite dramatically. To spot as many Perseids as possible find a dark observing site with an unobstructed view of the sky. Then scan a large area surrounding the radiant without directly looking at it. The reason being that although the meteors originate from the radiant they often actually appear many tens of degrees from it.
Perseids Data Table 2016
|Meteor shower name||Perseids|
|Activity||July 17th -> August 24th|
|Peak Date||August 13th|
|RA (J2000)||02hr 27m|
|Notes||Prolific meteor shower that was first recorded in 36 AD|
Comet 109P/Swift-Tuttle Data Table (at epoch April 18, 2013)
|Classification||Halley-type comet (NEO)|
|Discoverer||Lewis Swift / Horace Parnell Tuttle|
|Discovery date||July 16th, 1862|
|Orbital period (years)||133.285|
|Last perihelion||December 11th, 1992|
|Next perihelion||March 26th, 2126|
|Notes||Also known as Comet Swift-Tuttle|