Tue Jun 11, 2002

Cheaper than Hubble

There was an annular eclipse yesterday. The Sun’s disc was partly covered by the Moon. In the U.S., the best place to view it was in the southwest. (The further you were in this direction, the bigger the bite the Moon took out of the Sun.) As it turns out, there aren’t many places further southwest than Tucson. So I had a great view. Almost 75% of the Sun was covered at one point. Of course, you couldn’t look at the Sun directly to see this.

Which brings me to the amazing piece of technology pictured to the right—- the HRPSIS Mk 1. (Click on the image for a larger view.) The Healy Reflective Pinhole Solar Imaging System is shown in its operational location on the ground in our yard. The product of several minutes of careful, privately funded research and development, it consists of a shaving mirror covered with a piece of paper which has a small hole punched in it. When positioned at the right angle, the HRPSIS projected the Sun’s image through the small side window and onto the inside of the far wall of the living room.

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With all the other blinds closed, I got a nice image of the partially-eclipsed disc of the Sun. (Click the image for a larger view.) Cool. There’s a bit of distortion because I had to bounce the image at a steep angle. But that’s OK: by projecting it onto a distant surface (about 25 feet away) the image was nice and big but still relatively sharp. Normally pinhole mirror images like this are a lot smaller. I was lucky to be able to project the image though a small, recessed, eastward-facing window that wasn’t getting any direct sunlight. The main living-room window looks North, so I could just pull the blinds down on that one. The West-side wall has no windows, and the inside is conveniently painted white.

I feel the cost/benefit ratio of the HRPSIS Mk 1 is comparable to slightly larger but otherwise similar projects such as the nearby Kitt Peak Solar Telescope.

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