General Astronomy, 29:61
Fall, 2004
Second Homework Set...September 3, 2004. Due September 10, 2004

Show calculations and give reasons for your answers. Don't go around confused and despondent; if you do not know how to get started, ask us for help. The purpose of problem sets is to promote thinking and lead to understanding, not produce a confiteor of revealed truth. Note: Data for many of these problems should be read from the SC1 chart.

(1) You are on a cruise ship in the Caribbean, having such a good time that you have no idea where you are. It is night, and you notice a very bright star due south, low above the southern horizon. Consulting your SC1 chart, you identify it as Canopus, $\alpha$ Carinae (leftmost quarter of the chart, in the bottom panel). It is on the meridian. You devise a simple angular measuring device and measure its altitude angle as 20 degrees. What is your latitude?

(2) The star Arcturus (now in the western sky) is one of the brightest stars in the sky. (It is on the right hand portion of the SC1 chart, near Right Ascension 14 hours). What is the altitude angle at transit of Arcturus here in Iowa City? The latitude of Iowa City is $41^{\circ}39^{'}$.

(3) You are transported to a planet with an orbital period about its star of 6 months. The rotational period of the planet (=sidereal day) is 40 hours. What is the mean solar day on this planet?

(4) It is November 1. At what time of day or night does the bright star Rigel ($\beta$ Orionis, Right Ascension about 5 hours) transit?

(5) On June 1, what is the angle between the Sun and the bright star Aldebaran ($\alpha$ Tauri)? For the purposes of this problem, you may measure the angle from the SC1 chart.

(6) You are in Tromso, Norway. The latitude of Tromso is $69^{\circ}30^{'}$. There are days in the winter when the Sun never rises. Explain why this is true. What day of the year does the Sun disappear (i.e. doesn't rise at all) and what day does the Sun rise again for the first time?

(7) It is midnight on January 3. What is the sidereal time? Name a bright star on the meridian.

(8) If a star rises in the northeast, in what direction does it set?