Homo sapiens have been astronomers since they first looked up into the nighttime sky and wondered about its contents. For thousands of years, ancient cultures built monuments and mythologies around the night sky. Today, technology facilitates a deeper understanding of the Cosmos. Billion dollar telescopes orbit the Earth, colossal telescopes adorn mountaintops in remote locations and backyard astronomy is an increasingly popular hobby.
Astronomy is the study of celestial objects and phenomena that rise beyond the Earth’s atmosphere. You do not need $5,000 worth of telescope equipment or an astrophysics degree to enjoy stargazing. All you need are open eyes and a curious brain. The moon, five planets, various deep sky objects and thousands of stars are available for observation with the unaided eye. Smart phone apps and printable star charts are widely available to assist in getting acquainted with the night sky.
Galileo first used telescopes in the 17th century. Today, there is a wide range of telescopes available for the backyard astronomer. Currently, I observe with an 8-inch Dobsonian telescope (a simple design utilizing an 8-inch primary mirror, reflecting light into a secondary mirror, through an eyepiece and into my imagination). This is a great beginner-intermediate scope, providing stunning views of the moon, planets, double stars, nebula, star clusters and galaxies.
As fall arrives, two of the best objects for backyard stargazing include Jupiter and the moon. Jupiter is currently rising in the east around 9:00 p.m. and is the brightest object in the sky until the brightest star, Sirius, rises in the constellation Canis Major into winter. Through binoculars, Jupiter appears with the four Galilean moons, lined up in orbit. Through even a moderate telescope, Jupiter appears with striped equatorial storm bands and possible big red spot sightings. Saturn is currently visible on the western horizon at sunset, but quickly follows the sun into the ocean.
The moon is a remarkable object, orbiting Earth 250,000 miles away. The only other celestial object to host humans, Luna starts new each month in the shadows, waxing and each night until the full moon rises as the sunsets, and then waning and disappearing until made new again.
Some astronomers see the waxing moon as light pollution, obscuring deeper sky objects like nebula and galaxies. However, moon gazing entails many fascinating investigations. The next full Moon is Oct. 12 and people might assume that this is the ideal time for observations. This is not true. The Lunar Terminator is the dark line that represents day and night on the surface of the moon. It creates amazing detail for telescopic viewing. At the Terminator, mountain peaks cast shadows, crater rims glow and canyons emerge below the surrounding plains. Observe the moon during the first week of October and watch the terminator change each night.
The dark night sky is a precious natural resource. It deserves our consideration and care. Light pollution affects research instruments, backyard telescopes and the navigation capacities of migrating birds. Turn off outdoor lights when they are not needed.
The Bortle Dark Sky Scale measures the amount of light pollution in a given area. Exceptionally dark skies are rated black. The nearest black skies are found in the deserts to the east of San Diego.
The scale moves from blue to green, yellow orange and red moving from rural to suburban areas. City skies are rated white. The North San Diego Coast is rated a moderate yellow. However, the ocean stabilizes the atmosphere above us and provides what astronomers call “good seeing.”
San Diego has a fun and active astronomy community. The San Diego Astronomy Association (SDAA) hosts star parties throughout the county, including “Stars in the Park” on the first Wednesday of each month in Balboa Park. Separately, the “Explore the Stars” program takes place during the new moon each month from April to October at the Palomar Observatory campground. From 1948 to 1976, San Diego boasted the largest telescope in the world. The 200-inch Hale Telescope on Palomar Mountain continues to further the field of astrophysics and is open daily for docent-led tours. It is an amazing instrument!
Astronomy is a fascinating hobby available to everyone. With unaided eyes, binoculars or telescopes, innumerable discoveries are waiting. Look up and enjoy the wonders of our Cosmos. Here’s to clear, dark skies!
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