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/commentable: Adjusting the Moon
Dinarius = digital interest
30 April 2012

Adjusting the Moon

In an earlier post, I set about constructing a telescope to catch last month’s full moon. I never fastened down the primary mirror and so had an incredibly hard time accomplishing anything. After a little soul-searching and added brightness in my life, I commited to the location of the Mirror Cell and moving the telescope became easier.

Photo by sweetheart, Dana Kee

Photo by Dana Kee

I’m a moon half-full kind of guy. The air is cooling off for the day, dough is in the oven baking into crusty four-hour bagettes and wine is flowing on the deck off my living room. I lament how my Exposition of Light will feel incomplete without some shot of the moon, no matter how crumby, appearing. That’s when I hear, “the moon’s right over your head.”

After a panicy scramble during the loaves’ second rise, the telescope is up, precariously, on some strange stand system that seemed like a good idea until I had to use it. I spend many precious minutes trying to just find the moon. The sun is still sort of up and the sky is positively blue. No halo or glow in the eye-piece to give me a clue where the moon is and no “finder” attached to the telescope body (another oversight on a LONG list of such mistakes).

Finally, two digital cameras come to bare upon the moon which is zipping across the diameter of the focuser faster than we can believe. With the 10x eye piece, we only see about one-fifth of the moon; the surface pitted and pocked with crystal-like clarity. The cameras, acting as focusers, don’t magnify nearly as much. The entire disk of the moon can fit almost three times across the same diameter. It’s no big loss. Over a hundred shots are taken at ISO’s 100 and 200 f-11 for just 1/30th and 60th of a second.

The blasting brightness of the moon becomes more so the lower the sun dips. One of a few pictures that came out in focus, barely, reveals the complexity of adjusting for the moon in photographs. It has its own “full scale” and wildly disrupts the “full range” of the whole picture (which includes the magnifying lens and my thumb. So disregarding everything but the craters themselves in this waxing moon, we can see in a histogram that the moon, fully loaded with bright whites and blackest blacks imaginable, occupies only a sliver brighter than middle gray.

That’s the band we’ll adjust for. The height of the spike in the histogram spells out just how much is going on there – when we collapse the sliders to that band, the contrast of the moon sets off a dazzling display of a full range of grays, bright spots, craters, desert-like plains and inky recesses that straight shooting can’t always coax from the subject.

Finally, the bread is risen and baked and I, abuzz with wine and tooling with a column of sky in my telescope and camera, have the Moon in grasp.

Favorite's the ARTICLE, not the SITE.