David L. Richards

July brings us a unique opportunity to see the two largest asteroids, Ceres and Vesta, appear extremely close on July 13. They are actually 58 million miles apart, but appear to lie within only 2 minutes of each other. (There are 60 minutes in one degree; the moon and sun span 30 minutes, or half a degree.)

They sit 7 degrees (one 7 x 50 binocular field) above Mars in Virgo.

For reference, the bright star Spica is right below Mars. Their brightness is right at the limit of naked-eye viewing; to separate them you will need binoculars.

Ceres is now classified as a dwarf planet, but this remains a seldom-seen event for these two big rocks.

Saturn and Mars remain prominent in the night sky. On July 5, Mars and the first quarter moon are separated by less than 1 degree, and two nights later, the waxing gibbous moon and Saturn are only a degree apart.

The first of the month reveals brilliant Venus in the early dawn about 15 degrees above the eastern horizon in Taurus. Within a few days, Mercury appears on the horizon, approaching Venus, then receding from her over the next few weeks.

Jupiter sets at 10 p.m. on Tuesday, then disappears below the horizon for the remainder of the month.

The Southern Delta Aquariid meteor shower peaks during the dawn hours of July 29. Considered a strong shower, the Delta Aquariids average an observation rate of 15 to 20 per hour, with a peak rate of nearly 18. Astronomers recently determined that this shower originated from the breakup of what are now the Marsden and Kracht Sungrazing comets, less than 10-year-old fragments of a more massive earlier object.

Q&A

Q: Where do meteors come from? — D.T., Akron

A: Most of the 10 or so meteors you may see from a clear dark spot every night originate in the Oort Cloud, an enormous sphere of icy rocks, methane and water surrounding the sun, with the “edge” almost one light-year distant.

Transported to the inner solar system by comets circling the sun, this primordial material is left behind as a debris field from the sun-melted comet’s tail. When the Earth encounters this trail of fragments — called meteoroids in space, meteors as they glow from the ionized air trail shooting through our atmosphere, and meteorites if they reach Earth — are usually about the size of a pebble or grain of sand. About 16,000 tons of material fall to Earth each year from the heavens.

The very large and bright ones, such as the Chelyabinsk meteor that vaporized over Russia in February 2013, are called fireballs or bolides. Astronomers suggest that most bolides originate in the asteroid belt. Only two events of this magnitude have occurred in the last century, both over Russia.

Be aware also that some of the “meteors” you see may just be space junk — bits of man-made satellites, rocket bodies and tools that return to Earth with a fiery flourish.

Planetarium presentation

The Hoover-Price Planetarium is presenting The Universe at Large, our ongoing program for 2014. Along with the current sky, we will be presenting and updating material to reflect new discoveries, astronomical events and NASA’s ventures. This format provides us with more flexibility to respond to questions.

The program is shown at 1 p.m. on Saturdays and 2 p.m. Sundays. Through Labor Day, we will also have a presentation at 1 p.m. weekdays. The planetarium is included with admission to the McKinley Presidential Library and Museum in Canton.

David L. Richards is director of the Hoover-Price Planetarium at the McKinley Presidential Library and Museum, 800 McKinley Monument Drive NW, Canton, 44708, www.mckinleymuseum.org. He can be reached at 330-455-7043 or email hooverpriceplanetarium@hotmail.com.