August 2021
The Backyard Astronomer
by
Adam England

The Dog Days of Summer and Giants at Opposition

On the Scope or on Your Back in the Grass

We often hear “the dog days of summer” used to describe a seasonal period of stagnation or inactivity, usually brought on by long days and extreme heat. In the Arizona central highlands, much as our ancient predecessors experienced in Greece and Rome, this time correlates with the beginning of the monsoon season, connected with heat, drought and sudden thunderstorms.

While we may feel like spending this time lying in a backyard kiddie pool with our dogs, the term has absolutely nothing to do with terrestrial canines, and everything to do with astronomy.

The three stars of Orion’s belt point almost directly to the bright star Sirius, which in ancient times returned to view in the northern hemisphere during the hottest phase of summer, just prior to the annual flooding of the Nile River valley. As the brightest star in the sky and part of the constellation Canis Major (“the Greater Dog”), it is often called the Dog Star, and from this reference we still call this time of year the “dog days of summer.”

This year we can experience the opposition of both Saturn and Jupiter during this time, as we reach closest approach to these gas giants on August 2 and 19, respectively. Just a few days on either side of the August 8 new moon s the best opportunity of the year to view details of these planets and their natural satellites.

With the sun giving us the brightest illumination on these evenings, even smaller and medium-sized telescopes can pick out the weather bands of Jupiter, ring divisions around Saturn, and a handful of moons around each.

Specifically with Jupiter, watch over consecutive nights and sketch the locations of the four Galilean moons you see, documenting how they change position during their orbits from evening to evening.

Join us on the evening of August 7 at Pronghorn Park in Prescott Valley for an opportunity to view these and other objects in the night sky!

If you would like to learn more about the sky, telescopes, or socialize with other amateur astronomers, visit us at prescottastronomyclub.org or Facebook @PrescottAstronomyClub to find the next star party, Star Talk, or event.

Adam England is the owner of Manzanita Financial and moonlights as an amateur astronomer, writer, and interplanetary conquest consultant. Follow his rants and exploits on Twitter @AZSalesman or at Facebook.com/insuredbyadam.