Friday, December 31, 2010

Another Solar Transit

This is some cool digital photography, not to mention a good use of photographic processing software:
Caption: Looking back on the year, have you wondered where the Sun was in the sky each day during 2010 at exacty 9am UT? Of course you have. Search no further for the answer! It was somewhere along this celestial figure 8 curve known as an analemma. Recorded from a residential backyard in the small town of Veszprem, Hungary, this composite analemma image consists of 36 separate exposures of the Sun made at 9:00 UT, spaced throughout the year, plus a background image made without a solar filter. The background image was taken on the sunny afternoon of October 9 (13:45 UT). On the left is the photographer's shadow. The positions of the Sun at the 2010 solstice dates are at the upper (June 21) and lower (December 21) extremes of the analemma curve. On the equinox dates (March 20, September 23) the Sun was along the curve half way between the solstices. The tilt of planet Earth's axis and the variation in speed as it moves around its elliptical orbit combine to produce the graceful analemma curve.

Image credit: Tamas Ladanyi/NASA

This picture was taken in Veszprém, Hungary, according to that Astronomy Picture Of The Day (APOD) caption, and the gallery page. As you can see from the shadow in the lower left hand corner, Tamas Ladanyi photographed the Sun by setting up the camera in the same place every week or so for a year. That in itself took a bit of determination and planning. Then he processed it to superimpose the Sun's position on one particularly nice photo.

Interestingly, Veszprém's latitude (47.1 N) is nearly the same as Seattle's (47.6 N). If I were to do such a thing from my house, the result would probably be similar, assuming I had both the wits and the determination.

Apparently, not many people have had those traits in regards to this sort of thing. This page of analemma pictures from Greece claims that only seven people have done it. Of course, if I did that here, most of the images of the Sun in the lower part of that figure eight would be just fuzzy gray patches.

Anyway, like the NASA Astronomy Picture Of The Day site where I found this picture, I can't think of a better photograph to wrap up the year.

Happy New Year.

Afterword: Visit Tamas Ladanyi's site to see some other interesting astronomy photos. He has some good photos of sunspots, among other things.

For a full size image, go to either the APOD page, or the photographer's gallery to see.

1 comment:

Dana Hunter said...

That kind of stuff is so awesome. Too bad we don't usually get to see it.