Time for August’s shower
By Vernon Whetstone
The meteors are coming, the Perseids that is. The annual August meteor shower that some astronomers have called the best one of the year; it will peak between midnight on Aug. 11, and sunrise Aug. 12.
The best time for viewing is between 10:30 p.m. MDT on Sunday, Aug. 11, and 4:30 a.m. MDT on Monday, Aug. 12.
Meteors, those, brief streaks of light, are from tiny bits of debris left by comets when they orbit into the inner solar system on their trek around the Sun.
This particular debris stream was caused by Comet 109P/Swift-Tuttle.
It has an orbital period of 133 years and was last in our vicinity in 1992 and won’t be back until 2126.
Those bits are usually no larger than a grain of sand. They cause so much light because their enormous speed encountering the atmosphere increases friction and they literally burn up.
A meteor shower happens when Earth travels through the stream of debris left by the comet.
Each meteor shower has a radiant, a point on the sky where the streaks of light seem to originate. With the Perseids that point is located in the constellation Perseus which rises at about 10 p.m. MDT and will be above the horizon, best for viewing by midnight.
How do I view a meteor shower you ask? Well, you won’t need binoculars or a telescope.
All you need is your own two eyes, a very dark-sky location—preferably out in the country away from city lights, a clear view of the eastern horizon—and a friend or two to enjoy them with.
A reclining lawn chair or a blanket to spread out on the ground will be nice too so you won’t have to keep cranking your neck all the time to look up.
The early morning viewing time is best because that is when the side of Earth you are standing on will be facing in the direction of Earth’s orbit.
In other words, we are facing forward and can see the meteors coming head on.
Sort of like when you are driving through a snow shower at night. In the headlights the snowflakes all seem to be rushing right at you; it is the same with a meteor shower. It will look like they are all rushing at us.
Now, here is the caveat—don’t expect the sky to be filled with meteors. At best the Perseids produce between 60 to 100 meteors an hour. That is about one a minute which is why you have to keep looking.
And you won’t have to keep looking at Perseus all the time either. The meteors can appear anywhere in the sky.
The short, quick streaks are probably the ones coming at you.
The longer streaks are the ones we are viewing from a side angle.
If it is cloudy don’t worry. The shower will still be in good form Monday evening into Tuesday morning.
In fact you will most likely be able to see Perseids clear into the middle of the month.
SKY WATCH: New moon yesterday, so, tonight and tomorrow night will be a great time to look for the slender crescent of the moon in the west.
Don’t forget to look for Earthshine, especially in binoculars. In fact, look Friday evening about an hour after local sunset for the lunar crescent near Venus in the west.
Since you will be out looking for Perseids on Monday, don’t forget Spica and Saturn in the southwest. Saturn is the one on the left.
NEXT WEEK: More astronomical blathering.