(Adopted from Universe, Ch.3, with some modifications)
| 01. |
(a) The Moon moves noticeably over the space of a single night. To show
this, calculate how long it takes the Moon to move through an angle
equal to its own angular diameter (0.5◦) against the background of
stars. Give your answer in hours.
(b) Through what angle (in degrees) does the Moon move during a 12-hour night? Can you notice an angle of this size? |
| 02. | During an occultation, or "covering up," of Jupiter by the Moon, an astronomer notices that it takes the Moon's edge 90 seconds to cover Jupiter's disk completely. If the Moon's motion is assumed to be uniform and the occultation was "central" (that is, center over center), find the angular diameter of Jupiter in arcseconds. (Assume that Jupiter does not appear to move in the sky during this brief 90-second interval.) |
| 03. | One definition of a "blue Moon" is the second full moon within the same calendar month. There is usually only one full moon within a calendar month, which is why the phrase "once in a blue moon" means "hardly ever." Why are blue moons so rare? Are there any months of the year in which it would be impossible to have two full moons? Explain your answer. |
| 04. |
On June 21, 2001, residents of southern Africa were treated to a total solar
eclipse.
(a) On what date and over what part of the world will the next total eclipse of that series occur? Explain. (b) On what date might you next expect a total eclipse of that series to be visible again from southern Africa? Explain. |
| 05. |
(** Observing project homework; to hand in within 4 weeks)
To examine whether the moon really has a larger angular size when closer to the horizon, please devise a way to measure its angular size at different times on the same day when it is closer to the horizon and high up in the sky. Please describe details of the method you use, altitude angle of the moon at measurement, and the results with properly assigned error bars. |