August 17 th to September 20 th General Information August/September: This remains a period best suited for viewing star clusters and nebulae. Early on, most of the brightest galaxies (other than M31 and M33) are in the western sky. Three months past opposition, Saturn’s now in the western sky as darkness falls, with Neptune and Uranus the only other planets in the evening sky. Our view of the Milky Way begins a long transition from looking toward its inner arms and brighter regions to looking toward the outer, dimmer arms of the fall and winter ahead. Sunset Range: 8:09 p.m. (August 17 th ) to 7:20 p.m. (September 20 th ) End of Astronomical Twilight (Full Darkness* – Sun 18° below horizon): 9:45 p.m. (August 17 th ) to 8:48 p.m. (September 20 th ) * Usually dark enough for observing about a half hour before this.

Moon Phases – August/September August 22 nd – First Quarter Moon August 29 th – Full Moon September 5 th – Last Quarter Moon (Observing at Cahas on 4 th and 5 th ) September 13 th – New Moon (Observing at Cahas on 11 th and 12 th ) Roughly speaking: First Quarter Moon is highest at sunset and sets at midnight Full Moon rises at sunset and is in the sky all night Last (or “Third”) Quarter Moon rises at midnight and is highest at dawn New Moon sets with the sun and is absent from the sky all night

Celestial Events August 17 th to September 20 th August 18 th : Moon at apogee; distance Earth radii. August 20 th, 5:40 a.m.: Challenge Photo Op – Mars 0.22° S of Beehive Cluster (M44), 7° high in the east, one hour before sunrise. August 21 st, 8:09 p.m.: Challenge Binocular Observation – Saturn at eastern quadrature. Find it at sunset, 90° from Sun, 33° high and 9° E of crescent moon, using arms and finger measurements. August 30 th : Moon at perigee; distance Earth radii (11.7% closer than August 18 th apogee). September 1 st, 4:00 p.m.: Equation of Time is 0. September 4 th /5 th, 12:35:20 a.m. (approx.): Challenge Telescopic Observation – In the east, occulted Aldebaran reappears from behind dark limb of the 5° high last-quarter moon. September 14 th : Moon at apogee, distance Earth radii; 2015 max.

Orbits and planet sizes not to scale Mean Distance from Sun (AUs) Mercury: 0.39Jupiter: 5.20 Venus: 0.72Saturn: 9.52 Earth: 1.00Uranus: Mars: 1.52Neptune: Pluto: Planets’ Positions July 20 th (last meeting date) August 17 th

July 20 th, 9:45 PM Last month’s meeting date. Meridian August 17 th, 9:15 PM Meridian It’s getting darker earlier. Saturn Moon

August 17 th, 9:15 p.m. Sualocin Rotanev Delphinus Great Sagittarius Star Cloud NGC 6281 “Little Cat’s Eyes” (Mu Scorpii) Moon Saturn

Pluto The “Teaspoon” The “Teapot” You’ve seen the movie. You’ve even bought the T-shirt. But now get prepared for the real...

Spaceballs

Sun Earth Jupiter 2mm bead Earth Moon 17 days to circumnavigate at 60 mph 5 years to circumnavigate at 60 mph Key to Demonstrations – Help people relate to how much these objects shrink the reality.

Questions ???