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B. Lowe-Schmahl, K. Schmahl, T. Mengel (A Schmahl Science Workshop), E. Schmahl (NASA/GSFC)
Our 4-7th grade Workshop students made a working prototype of a HESSI rotating modulation collimator (RMC) using PVC pipe, PVC couplers, grid transparencies, a dot matrix (tractor feed) printer, and a slide projector. The idea is to rotate two four-inch long telescopes end-to-end on the same printer roller. Each telescope has two grids and are placed an inch or two apart. They have the same rotational axis and all the grids are parallel. The light beam comes in and hits the imaging telescope. The light going out of it hits a diffusion screen (translucent plastic) and then continues, diffused, into the back-projection telescope. Polaroid film and a modified Polaroid camera sum the back-projection data. The camera is modified by removing the front focusing lens, replacing it with a 4-inch lens, creating a shutter system using layered cardboard and gluing the shutter system to the front of the camera. The shutter system is opened and the film exposed through one complete rotation of the model HESSI Telescope. To our students' amazement a back projection was successfully obtained on the print!
The HESSI Telescope Demonstration project provides the impetus for students to stretch their mental boundaries. This project promotes the goals of ``learn one, do one, teach one": 1) Learn one: students must research the field and subject matter for the telescope; 2) Do one: By designing, developing and implementing their project, they are in essence performing valid research, which is the end result of all scientific inquiries; 3) Teach one: By incorporating both written and oral presentations of their projects and through interaction with a scientist and/or engineering mentor, students are given the unique opportunity to experience the peer review process that all scientists and engineers must undergo.
We would like to thank the HESSI team of NASA Goddard Space Flight Center for their on-going support of our students' project.