The Projects for the Sun and Moon

SUN: Sunrise, Sunset Azimuth Positions

The Sun does not follow the same path across the sky every day. In the summer at northern latitudes, the Sun is high at midday, and in the winter, it is low in the southern sky. By observing the relative positions of the Sun at dawn or dusk, one can establish that the Sun does indeed shift along the horizon. Note where the Sun sets or rises once a week for at least four weeks in the spring or fall and for 6 to 8 weeks in the summer or winter. Be certain to observe from the same position each time. Note the time, day, month and year of each observation. At what season is the shift most noticeable?

MOON: Maria

A naked eye or binocular view of the Moon shows two distinct types of lunar surface material, the maria and the highland areas. Both areas have their own visual characteristics. The highland material reflects light to a greater degree and appears very rough in character. The various mare areas are much darker and appear smoother. Before the telescope, these dark areas were speculated to be bodies of water, hence their name mare which is sea in Latin. Observe these "seas" or maria with your telescope. What evidence do you find that these are not bodies of water?

MOON: Highlands

Examine the bright, rough areas of the Moon. These are called the Lunar Highlands. If we are to assume that craters formed everywhere on the Moon at approximately the same rate, what can you conclude about the relative ages of the Lunar Highlands and the darker Maria? Why?

MOON: Crater Ages

Twelve degrees south of the Lunar equator and about halfway from the eastern limb (Selenographic east, not east in Earth's sky) to the center of the Moon is one of the most prominent craters on the Moon. Theophilus is 100 km (62 miles) in diameter and has a terraced wall and a group of central mountains. Just to the south and west of Theophilus is another crater of equal size, Cyrillus. Remembering that the Lunar surface is constantly being eroded away by countless meteoroid impacts, which crater would you say is the oldest and why? Sunrise on Theophilus is five days after New Moon. A six or seven day old Moon should show the area well.

MOON: Scarps

The Straight Wall, or "Rupes Recta" in Latin, is the best known scarp (fault area) on the Moon. When viewed less than a day after First Quarter, the fault's long thin dark shadow is hard to miss. Contrary to its appearance, it is a moderate slope and not steep. The Straight Wall is located at 22° South and 7° West. Just to the scarp's west is a small sharply defined crater called Birt. If Birt is known to be 17 km. (10.5 miles) in diameter, estimate the length of the Straight Wall.

MOON: Occultations

Lunar occultations occur when the Moon, in its eastward path about the Earth, passes in front of stars or planets and eclipses them. The precise timing of the occultation concerns that instant when the occulted object seems to blink out behind the Lunar limb or reappears from behind the Lunar limb. These timings supply vital information regarding the Earth-Moon orbit and any changes in the velocity or distance of that orbit. Less frequent, but neater to observe, are occultations by the moon of the naked eye planets. These events, both of stars and planets, are always highlighted ahead of time in the astronomy magazines. Occultations of stars in the Hyades cluster are fairly common. Periodically also, the Pleiades cluster is crossed by our natural satellite. If this type of observation is appealing to you there are resources available that tell you how to do really worthwhile and productive work. You will need to have a telescope available, however. See the resources in the back of the book. Note the name of the object occulted, the day, month, year, the universal time of the object's disappearance and reappearance, and the place of your observations.