The Perseids are one of 2 annual showers worth getting up early for. This year the peak will occur on the morning of August 12 though a bright Moon will decrease the number of visible Perseids.
Some of you may have seen this meme circulating around the internet.
Well… it’s complete BS. The Perseids are a good strong shower year after year but they have shown little propensity for outbursts and even at their best will produce a very small fraction of the number of meteors seen during true meteor storms. For example even under the darkest sky and no Moon, the Perseids (at their best) would produce no more than 200 meteors per hour. This year the number will be much lower due to the bright Moon and the fact that no special activity is expected (no more than 20-30 meteors per hour and probably less for most observers). True meteor storms like the 1966 Leonids produced 10,000 of meteors per hour.
Here’s what some of the foremost meteor shower experts are saying about this year’s Perseids. From the International Meteor Organization’s 2017 Meteor Calendar:
…the full Moon on August 7 will then affect Perseid (007 PER) observations before and around the peak. In the maximum night the Moon is placed in Pisces and thus illuminates the time during which the radiant has a reasonable elevation. The mean or ‘traditional’ broad maximum varied between λ⊙ ≈ 139 . ◦8 to 140 . ◦3, equivalent to 2017 August 12, 14h to August 13, 02h30m UT.
The best time to see Perseid activity is when the radiant lies highest above the horizon in a dark sky. For most potential observers this occurs near 4am local daylight saving time. At this time you should be able to see 20-30 Perseids per hour, depending on the transparency of your sky. These rates are better than most of the major annual showers so it is definitely worth trying to view the display this year despite the moonlight. There will also be other meteors visible besides the Perseids. These meteors will be far less numerous and will possess varying velocities and paths through the sky. If you are clouded out on the evening of August 11 or the morning of the 12th, meteor activity will still be good the following night and for a few nights after. The good news for Perseid observers is that the 2018 display will occur near a new moon, when the moon is located near the sun and not visible at night.
The International Meteor Organization also hosts a display of Perseid rates that is updated live as observations are reported to the organization.
The Perseids were produced by Comet 109P/Swift-Tuttle which orbits the Sun once ever ~135 years. This comet was discovered by American astronomers Lewis Swift (Marathon, New York) and Horace Tuttle (Cambridge, Massachusetts) in July of 1861. During that return the comet reached a bright 2nd magnitude and developed a tail up to 30° long. The comet returned late in 1992 and brightened up to 4th-5th magnitude. Based on our updated knowledge of Swift-Tuttle’s orbit it is now known that the comet was also seen in 1737 and likely seen in 188 AD and 69 BC.
Back in 1992, Tim Spahr and I used the Catalina schmidt to take a photographic image of Comet Swift-Tuttle (seen below).