August 2017 Menu

Totality photographed from Baja California, 1991.

Image Credit: Steve Albers, Boulder, CO; Dennis DiCicco, Sky and Telescope; Gary Emerson, E. E. Barnard Observatory

Astronomy in August
Perseids Precede the Big Event

Uncle Bob

Perseid Meteors

This annual event will peak on August 12. The rather large moon rising around midnight will diminish our capacity to see many of the shooting stars. Meteors showers take place at various places in Earth’s orbit which are littered by debris from previous comet visits. So annual shower times are predictable, but not their intensity. Or count.

Meteors can happen at any time though. Claire and I saw a very bright white one through our front windshield at around 10 pm on this past July 26. We saw at least 10 degrees of a descending arc appearing nearly vertical. The Sky & Telescope daily calendar has some interesting meteor factoids – not to be confused with meteoroids, of course.

Earth’s atmosphere is bombarded by 40,000 tons of space matter annually.

Most of it burns up completely but a few weighing a couple of pounds will strike an area the size of Texas each year. Those are the meteorites.

Meteorites are easy to spot in Antarctica, if you are into that sort of thing.

It is possible for space junk, even asteroids, to fall into and follow Earth’s orbit, either leading or trailing our planet. So far, one “Earth Trojan” asteroid has been discovered.

The Big Event

Although a total solar eclipse will occur on Earth every year or two, many happen in inaccessible places, or on cloud tops, and they last only a very few minutes. So the one predicted to cross the entire continental United States on August 21 is a big deal. Last month we published resources to help you access this event safely. That issue of Uncle Bob is still available at

Remember that it is not safe to look directly at the Sun when it is only partially eclipsed. You must use a filter. To be safe look for the rating ISO 12312-2 on the product. That said, there are some inventive ways to view the eclipse indirectly.

1. Try a round pin-hole camera. Poke a hole in an index card and focus the image underneath.
2. The Annie Oakley. Point small binoculars – one lens covered – backward over your shoulder and project the image onto a sheet of paper. Putting a cardboard shield around one lens will help control contrast and brightness.
3. Look at the ground under a leafy tree. You should see a multitude of effects similar to the pinhole projection.
4. Be hands on. Overlap the fingers of your hands perpendicularly to make 8 or 9 ersatz pinholes.

Source: MacRobert, Sky & Telescope, August, 2017, pp.48-51

Enjoy this rare event and enjoy it safely. One of my favorite quotes is Tom Peters’s, “If a window of opportunity appears, don't pull down the shade.” I cited it in my memoir in the chapter on astronomy. Oh right! Have I mentioned my memoir? It’s on sale at the Uncle Bob Store.

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