Observing the Tuesday night sky

1. Observing the Tuesday night sky • Engage: Use the Big Dipper to find the North Star, Arcturus, Cassiopeia. Find Summer Triangle, Milky Way. • Explore: Students make a sample observation of a two fist by two fist section of the sky that contains a bright star. Compare entries with a neighbor. • As a class, brainstorm characteristics of an effective sky observation and an effective notebook entry. • Explain: Outline Earth’s two main motions (rotation and revolution) and how those affect observations • Review the use of a planisphere (star wheel) • Practice using a star wheel • Elaborate: Outside naked eye observations using star wheel as a map • Telescope observations of Jupiter, Jupiter’s moons (Europa, Ganymede, Callisto), Neptune. Three of Jupiter’s moons and Neptune contain solid and maybe liquid water • Evaluate: Use star wheel to identify two objects in the sky chosen by the instructor.

2. Layout of an observation entry • Heading for each entry should include • Date and time • Location • Sky and weather conditions • Sketch observation on a grid with the x-axis being the horizon and the y-axis being the altitude. • Measure height above the horizon (altitude) and degrees from compass direction in fists. A closed fist held at arm’s length subtends an angle of about 10 degrees from top to bottom. • Add other interesting items and facts to your entry.

3. Using the planisphere (star wheel) To find the rising or setting time of a star • Locate the star on the planisphere. • Rotate the dial so the star is touching the eastern half (rising) or western half (setting) of the planisphere. • Find the date in question on the planisphere. • Read the time that that date is lined up with. (If daylight savings time is in effect, you’ll need to add an hour to the time you read.) • Practice question: What time does the bright star in the constellation Virgo rise on March 10?

4. Using the planisphere II To find the sky orientation for a specific day and time. • Find the date in question on the planisphere . • Rotate the planisphere so the time you want is lined up with that date. (Don’t forget about the daylight savings time correction.) • Now, you can look at the planisphere and determine where a star is located on any day at any time. • Practice question: When is the bright star in the constellation Leo due south at midnight?

5. Planisphere practice questions • What time does the bright star in the constellation Taurus rise on May 1? • What time does the bright star in the constellation Taurus set on May 1? • What time does the bright star in the constellation Bootes rise on October 10? • What time does the bright star in the constellation Bootes set on October 10?

6. Sample summer viewing chart