As you're reading this, millions of people across the United States are preparing to witness the Aug. 21 solar eclipse. The path of totality will span coast-to-coast from Oregon to South Carolina, but the rest of us will see varying degrees of partial coverage as the moon slides across the sun. Some estimates project that more than 220 million people will witness this event, making it one of the most highly anticipated sky events of all time.
Many of us across Houston will be watching the skies around midday on Monday. We caught up with Dr. Christopher Johns-Krull to chat about this rare event and what we can expect to see in our city.
Dr. Johns-Krull, why is there so much excitement about the "Great American Eclipse" on Aug. 21?
Total eclipses of the sun are very rare. A given place on the Earth will experience a total solar eclipse only once every 400 years on average. In my lifetime -- I am 50 years old -- there have only been two previous total solar eclipses visible in the continental U.S. One was in the northwest and one was in Florida and along the eastern seaboard. There was another in 1991 visible in Hawaii, though it was cloudy for most of the islands. In some ways, we are in a relatively rich time. After this eclipse, there will be another total eclipse of the sun on April 8, 2024, which will be visible from Texas to Maine. There will also be an annular eclipse of the sun visible from the continental U.S. on Oct. 14, 2023. However, these are still very rare events. Unless you are willing and able to travel, most people will never see a total eclipse of the sun.
Houston isn't in the path of totality this time, so what can we expect to see here?
At its peak, the moon will block out about 70 percent of the sun's disk. This will not be noticeable really, unless people try to view the eclipse in some way.
What's the best way to view the eclipse and keep our eyes safe?
First and foremost, do not look directly at the sun! NASA's statement on eye safety gives these guidelines:
"Looking directly at the sun is unsafe except during the brief total phase of a solar eclipse (“totality”), when the moon entirely blocks the sun’s bright face, which will happen only within the narrow path of totality. The only safe way to look directly at the uneclipsed or partially eclipsed sun is through special-purpose solar filters, such as “eclipse glasses” or hand-held solar viewers. Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the sun."
There are a number of ways that you can safely view the eclipse, though. People can purchase special glasses or filters to view the eclipse, though it is getting a little late now. It is important to make sure that you get such glasses from a reputable vendor. The American Astronomical Society has a solar filters webpage devoted to explaining this. There are also good vendors in Houston such as Land, Sea, and Sky who can help direct people to quality glasses at a reasonable price.
However, no special equipment is needed. You can make a pinhole in a piece of paper or cardboard and view the projected image of the sun with it. Over the course of the morning and early afternoon, you will then see an increasing then decreasing bite being taken out of the sun by the moon. Here are online instructions on how to make and safely use a pinhole camera. There will also be live coverage of the eclipse on NASA TV.
Is the Rice Department of Physics and Astronomy planning any public events?
Yes! We are still planning the event, but we will likely set up a few telescopes on campus to project the image of the sun and eclipse for people to view. Once finalized the week before the eclipse, details will be posted at: http://www.ruf.rice.edu/~ruco/observatory.html
Will Houstonians ever get a chance to be in or near the path of a total eclipse?
It will be quite some time before Houston is in the path of a total solar eclipse; however, the eclipse of April 8, 2024, will see the path of totality go through central Texas up to the northeast of the state, so a drive of only a few hours will get residents right in the middle of the path. There will be an eclipse on May 11, 2078, in which the path of totality will be just off the Gulf Coast. For the maximum of this one, only a very small sliver of the sun will be left visible in Houston.
After the Aug. 21 excitement is over, are there other upcoming opportunities for skywatchers?
The Rice Campus Observatory has monthly open houses during the school year to look through our telescope. On Nov. 13, there will be a spectacular conjunction of Venus and Jupiter. These two bright planets will be visible in the pre-dawn sky and will be extremely close, appearing only 0.3 degrees apart. Look for this impressive pairing in the Eastern sky just before sunrise. The Geminids meteor shower will peak on Dec. 13 and is perhaps the richest of the annual meteor showers.
Our thanks to Dr. Johns-Krull for all of this great information. If the eclipse has whetted your appetite to learn more about our fascinating universe, we invite you to join him for Galaxy Formation, Evolution and Cosmology at Glasscock School starting in September. He is also an instructor in our Master of Liberal Studies program.
Our director of community programs, Cathy Maris, also suggests this intriguing article on the psychology behind solar eclipses. We're always interested in mind-body topics here at Glasscock, so this is a very timely subject.
Also, be sure to check out some expert eclipse photography tips from photographer and instructor Tom Flaherty.
Be safe, and enjoy the show!
Image at top: Illustration depicts a rare alignment of the sun and moon casting a shadow on Earth. (NASA)
About Dr. Christopher Johns-Krull
Christopher Johns-Krull, Ph.D., is a professor in the Department of Physics and Astronomy at Rice University. His research focuses on observational studies of star and planet formation, with a particular emphasis on the search for extra-solar planets orbiting very young stars. Recently, teams led by Dr. Johns-Krull announced the discovery of a hot Jupiter orbiting a 2-million-year-old star. They also found evidence that a hot Jupiter orbiting another young star is being evaporated by intense radiation from the star. Dr. Johns-Krull has also taken part in the discovery of several additional hot Jupiters orbiting middle-aged stars like the sun.