May 30, 2020

Astro-Event of the Week, August 5th-11th, 2008: The Perseid Meteors!

   August always meant one thing for me as a kid; the Perseid Meteor shower . Arguably one of the  best, or at least most dependable meteor showers of the year, this shower also has the advantage of occurring in the middle of the northern hemisphere summer, when conditions are conducive to laying out under the stars for long stretches of time. The Perseids themselves will start picking up this week, with a predicted peak of the early morning hours of August 12th. These are so named because they appear to radiate from the constellation Perseus. Typically, this shower offers a Zenithal Hourly Rate (ZHR; see below) of about 60 per hour, but it will be worth watching a few days before or after, depending on your local weather. Now, for the good news; first, with the Moon passing New phase on the 1st, it’ll only be at 76% illumination and will set around midnight local time, right about when the action begins. Secondly, western North America is favored this year to take the brunt of the meteor stream, hailing from comet P109 Swift-Tuttle. Remember, you always see more meteors after midnight local; that’s when you’re on the section of the Earth facing forward, scooping out a big 8,000 mile tunnel through space. Any meteors that you spot in the PM have to catch up with us!

This week’s astro-term of the week is Zenithal Hourly Rate (ZHR). This is an idealized number of meteors that you would see from a given shower under perfect conditions. Why don’t you actually see this number of meteors? Here are some factors that affect it: 1. Light pollution. This affects your limiting magnitude. 2. The Moon. The brighter the Moon, the fewer meteors you’ll see. 3. The elevation of the radiant. The lower the radiant from your local vantage point, the more meteors slip down below the horizon. 4. One observer cannot cover the sky! At most, a lone viewer can cover maybe a 120 degree swath visually.

   Finally, don’t forget that meteor observing requires no equipment, just your eyes and lots of patience! If you want to get technical, record how many meteors you count hourly; this is a real scientific measurement that you can do!

Comments

  1. susan says:

    Hi. Thanks so much for the info. Live in north part of Glendale, Ca., about 20 minutes from the Los Angeles Crest mountains. Any suggestions on places to take the familiy to watch? Looking forward to it, and thanks in advance for your help!

  2. webmaster says:

    Any place that’s away from city lights; the darker, the better! Also, being on the west coast, you are predicted to see the peak the morning of August 12th. Good luck and clear skies!

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