Grazing Occultation
Project
Grade: 7 to adult
Object: to produce a map
of the polar regions of the moon by watching stars/planets 'blink' as they graze
the lunar horizon, going behind mountains/craters and reappearing on the other
side.
Methods: For this project, one needs a list of objects which the moon occults
near its polar regions. This list is available at the IOTA web site (listed
below). One also must know the exact latitude and longitude of one's observing
site (to within 50 feet).
Once one has aquired the object in the telescope, he/she must keep careful track
when the star blinks in and out as it passes across the lunar horizon. The
easiest way of doing this is by having a tape recorder and a radio. With the
radio set to the timing signal, one calls out each time the star appears and
disappears. The tape thus records both the signal and your 'calls'. If a whole
series of people are observing along a line, one can plot the calls and
accurately plot the surface features of that area (this is what IOTA does with
the tapes that are sent in). For more information or participation in this
project, contact the IOTA
website.
School Instruction: teachers can use this project to demonstrate how one reduces
data into meaningful information (in this case, a series of points into a two
dimentional map of the lunar surface). It also gives students an excellent
opportunity to participate in a scientific endeavor.
PS: For a more extensive article on Lunar Occultations, please see the
Occultation Article
in the Article Section.