Cynthia Vaskis

SLM521 – Spring 2004

Dropin3 Assignment

4/6/04

File: dp3sugg2.htm

Suggestion 2 - about a demonstration model to build.

As a longer term project, the students could set up a model of a shoe box taped to a table and run a string from it out its center viewing area to a chair in front of it. Then have them decide how wide the Field of View is (the radius angle) for the make-believe telescope in an angle measured out from the center string. Then set up an object (a star) somewhere in front of the box’s front (which will be the tracker’s telescope lens) and tape a string from the box’s lens to the “star” object. Have the student’s measure the angle between the two strings with a protractor. Then place another object (a second “star”) somewhere to the side of the box not in its viewing area. Run a string from that second star to the lens of the box and measure its angle to the box’s Field of View center string. The angle measured between the box’s center string and the string to the second star is the angle that must go into a rotational matrix if you want to point directly toward the second star. Have the students decide whether or they can get both stars in the Field of View at the same time and what angle of rotation would they have to move the box to do that? Then actually rotate the box on the table by that amount and run the strings to the two stars again. They will also have to change where the center string is headed by moving its chair directly in front of the box. Measure the new angles between the center viewing string and those to the stars. Are the angles less than the defined radius angle of the tracker (box) itself? If not, then those stars will not be visible to the tracker and either the tracker must rotate or the object it is on (the table or space object) must rotate to see the stars individually since those two stars are too far apart to see them together in the trackers Field of View. An easier way to do this would be to measure the angle between the two stars strings to the box and divide that number in half. If that new number id greater than the radius angle of the tracker’s viewing area, then both stars cannot be seen at the same time.