Monday, August 07, 2006

light table (or box) ideas

Got inspired (again) while reading The Backyard Astronomer's Guide when they mentioned a light table for backlighting star charts. An accompanying photograph showed a custom job that fit the Tirion Sky Atlas "Field Edition" sheets. I thought: I can build one of those! Quickly sketched a design, with little compartments for eyepieces, pens, etc., and noted some "requirements."

But then I considered how practically I might do this over the holiday weekend. Let's K.I.S.S. (keep it simple...)

I had already considered asking Mom if she still had a collapsible card table. Yep. Check.

And when I remembered my sister, an accomplished photographer, had a light box for examining slides, I asked her to bring it over.

I did not look at it until Monday morning. And immediately realised it would not have worked. Donna's slide viewer light box is quite... boxy. At approx. 30cm x 20cm x 20cm, it is bulky. The glass plate is too small for the Tirion sheets; they'd hang over the edge.

As I examined my sister's slide light box, Mom piped up and said that she had her own! Huh? It too was custom-designed but this time around a 40cm long fluorescent light bulb. This made for a wider and thinner box. It was much more like what I was expecting... Mom loaned it to test drive. So perhaps I'll use in around home during another backyard session. Or up at Awenda? I need to find some large sheets of red cellophane first though.

I'm still interested in building my own unit but that perhaps will run off a 12 volt supply and use red LEDs. Initially I had grand plans to build an entire table! While a custom table would be fun to have, with little pockets and drawers, it might be too grandiose, too complex, too heavy. If I can plop down a simple card table, then I just need a “standard” light box. Still, already, I see room for improvements: a handle on the side for easy transporting; a “firm” cover to protect the glass top; a double-pane glass top to hold the sheet down and reduce dew penetration.

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