Astronomy 1010 Planetary Astronomy Fall_2015 Day-6

Time to Re-Calibrate

Course Announcements Smartworks Chapter 1: Due TODAY! Grades will be downloaded on Saturday. No class Monday (Labor Day) Read Chapter 2.2, 2.3, 2.4 How is the lunar observing going? How is the sunset/sunrise observing going? Next week: Dark Night Observing on Tues. 9/8 & Thur. 9/10 Sat. 9-5: Football vs Mercer, 4pm; Tailgate at 1pm

Useful Information for Next Lab Rotating Sky ClassAction Web Site (Link from apsu.edu/astronomy) Print the instructions BEFORE you come to class!

Definitions & Terms -1 Circumpolar Star: A star which stays above the horizon at all times at the observers location. Zenith: The point directly overhead, 90° from all horizons (assuming they are flat). It does NOT have an azimuth associated with it. Nadir: The point directly under your feet, opposite the zenith Altitude: A measure of the height of an object from the ground up. It is measured perpendicular to the horizon. The horizon is 0° altitude. The Zenith is 90° altitude. Azimuth: The point along the horizon –measured eastward from the north point- where you measure the altitude. Runs for 0° in the North, to 90° due East, 180° South; 270° West.

Use the Big Dipper in the northern sky as a way to find other groups of stars

Use Summer Triangle to find constellations during evenings

Use Winter Triangle to find constellations during evenings

Stuff in Chapter 2 Coordinates Position Daily Motion (spin of Earth on its axis) Visibility of the sky Year Motion (Earth orbits the Sun) Seasons (tilt of the Earth’s axis) Precession of the equinoxes Motion and phases of the Moon Eclipses

Coordinates

Stuff in Chapter 2 Coordinates Position Daily Motion (spin of Earth on its axis) Visibility of the sky Year Motion (Earth orbits the Sun) Seasons (tilt of the Earth’s axis) Precession of the equinoxes Motion and phases of the Moon Eclipses

Celestial Sphere Celestial Sphere Rotation Celestial Sphere Star A Star B Figure 2 Horizon Is the horizon shown a real physical horizon, or an imaginary plane that extends from the observer and Earth out to the stars? Can the observer shown see an object located below the horizon? Is there a star that is in an unobservable position? When a star travels from being below the observer’s horizon to being above the observer’s horizon, is that star rising or setting? Position

Tutorial: Position – p.1 Work with a partner Read the instructions and questions carefully Discuss your answers with each other Come to a consensus answer you both agree on If you get stuck or are not sure of your answer ask another group If you get really stuck or don’t understand what the Lecture Tutorial is asking as one of us for help