Choosing one’s data

We contemplate activity during a very short time span.

This morning was very nice in Alexandria, cooler than the recent late-summer heat wave and much less humid, while still sunny.  Indeed, our photographer in particular remarked upon the brilliant light, wonderful for many types of pictures (though not all).  He was motivated to take out a camera and catch what images he could while the weather lasted.  But he didn’t.  He had scheduled himself for a run along the river, and his other activities make it difficult to reschedule such things, even leaving aside the vagaries of weather and unexpected events.  And exercise becomes much less effective when it is seen as optional.

Still, running on the bike path next to the river is in itself an enjoyment of the weather, and not at all to be despised.  Along the way he found himself pondering what to do for the upcoming total solar eclipse, next April 8.  He’s not yet sure where he’s going to be for it, but definitely plans on being on the path of totality, rather than seeing another partial event; there really is no comparison to be made between them.  One can only do one or two things during an eclipse, because totality only lasts a couple of minutes or so, which pass like so many seconds.  One must choose.

Although there are possible observations to make of some scientific value, there is much less opportunity than in the past.  The deployment of space probes covering essentially the whole of the electromagnetic spectrum, plus professional (and advanced amateur) equipment he cannot hope to match, means that our photographer is primarily interested in a sort of personal souvenir.

The main spectacle is the view of the solar corona.  It’s difficult to picture properly, because it varies so greatly in brightness with distance from the eclipsed Sun; it is a paradigmatic High Dynamic Range situation.  In the days of photographic film it was extremely difficult to handle, and our photographer’s results from the 1999 event in Germany were underwhelming.  Nowadays, when multiple digital exposures can be combined easily, much more impressive images result.  But the techniques involved are not those he has mastered, so he’ll leave that are to others.

He’ll probably do something with a prism.  His spectrum of the 1999 totality showed nine emission lines, impressing us (if no others) with how much could be accomplished with a camera, a prism and improvisation.  It would be good to get better optical alignment and adjustment; unfortunately, opportunities for practice are rather limited.  A good feature of this idea is that, in principle, he could do something even through clouds.

Lately, he’s been entertaining an heretical thought.  Kind of like this morning’s run, might he just discard the idea of capturing an image, and simply enjoy the experience?