Week 5

Read: The sun, the moon and the calendar (Chap. 8)
Quiz: Monday. Covers Ptolemy's Almagest.

Homework exercises: The moon and the zodiac (Ex. 8.1), Optional: Crescent moon (Ex. 8.2) Due noon Saturday week 5.

Laboratory exercises: In lab this week, we will discuss the upcoming Planetary observations (Ex. 3.2) and Lunar observations (Ex. 8.4). The planetary observations must be done at least once per week starting this week and ending on week 14. From now on, each week you must scan and submit a lab book page which includes your planetary observation for that week. Be sure to include the time, date, sky conditions, sketch, and measurements of the position of the planet with respect to nearby stars. Your first observation is due noon Monday week 6.

The lunar observations must be done every other night at the same time (say, 9 or 9:30 pm) from Oct. 21 until Nov. 1. Each night you should record the time, date, sky condition, observation location, location of the moon, and a sketch of the moon. Scanned lab book pages will be due noon Monday week 11.

The sun, the moon and the calendar (1 video):

Predicting solar eclipses

The ancient Babylonians used the so-called Saros cycle to predict the dates on which solar eclipses would occur. They could not, however, predict the location(s) on earth from which such eclipses would be visible. How can scientists today predict, to a high level of accuracy, both the location and time of visibility of solar eclipses? Check out this video from Quanta:

The Sidereal day versus the solar day:

There is a difference between one solar day (our traditional 24 hours) and one sidereal day (a period that is just under 24 hours). Here is a video from Veritasium on these two different definitions of the "day". It begins with a poorly-worded SAT question from 1982 that everybody missed (because the correct answer was -no- an option.)

Intro. to Astronomy