Objects & Observing Sites

Telescope Objects to View

There are many kinds of deep sky objects to see: the Moon, planets, stars, double stars, open star clusters, globular clusters, galaxies, nebulae, and planetary nebulae. 

Different size aperture and types of telescopes can give you different views of objects. The larger the aperture and the darker the skies the better most deep sky objects will look. PAS has come up with some of our favorite deep sky telescopic objects that look good depending on the size of the scope and the darkness of the night sky. (Darkness of the sky is shown in Bortle numbers. Bortle 1-3 is darkest, many miles away from any lights, like the antennas location Bortle 2. Bortle 4-5 is suburban or outskirts of the valley like Cave Creek or Carefree. Bortle 6-9 is inside the Phoenix city limits with various degrees of light pollution.) 

5 inch refractor telescope: 

6 inch Dobsonian reflector telescope: 

8 inch Newtonian reflector telescope: 

9 ¼ inch Schmidt Cassegrain telescope: 

14 inch Dobsonian reflector telescope: 

Viewable Objects with Binoculars

Even though most night sky objects look best in telescopes, binoculars can show galaxies, nebulae, globular clusters, open clusters, stars, double stars, the moon, some comets and Jupiter with its 4 Galilean Moons. 7 x 35 or 7 x 50 are the smallest recommended, and the standard 10 x 42 or 10 x 50 are even better. Astronomy binoculars like 20 x 80, or 25 x 100 can be very heavy and require a tripod to hold steady.  The first number is the power or magnification, and the second number is the diameter of the 2 big lenses in millimeters.   The bigger the diameter, the easier it is to see dimmer objects.

The following are some of the favorite deep sky objects PAS members enjoy with binoculars. We have listed the season of the year and the constellations to help locate them. 

Dark Sky Observing Sites

The darkness of the night sky can be measured in Bortle Units or with a Dark Sky Meter.  In February 2001, John Bortle published his famous scale in Sky and Telescope Magazine.  Bortle 1 is the darkest sky possible.  Bortle 5 is where the Milky Way is faintly visible to the naked eye.  Bortle 9 is very bright inner city skies with only a few very bright stars visible.  PAS has taken Bortle readings using a Sky Quality Meter about 2 hours after sunset with no moon or clouds present at various locations.  This can help you find a dark sky site near you.  The lower the Bortle number, the darker the skies and the more objects can be seen.  A 6 or 8 inch diameter telescope at a Bortle 1 or 2 site can look as good as a 16 or 18 inch scope at a Bortle 5 or 6 site.