"Henry Spencer" wrote in message
...
In article ,
Bruce Palmer wrote:
On some afternoons, depending on clouds and atmospheric dust, the sun
looks like a giant orange ball that you can actually look at without eye
damage as it sets...

A note of caution: safely low visible-light intensity doesn't necessarily
equate to safely low UV and IR intensity (especially the latter, which has
a tendency to penetrate clouds etc. better than visible light). Your eye
is not a reliable guide to what's eye-safe.

This is in fact my understanding of exactly why total eclipses are so
dangerous. You're not expecting the still high UV/IR does and your pupils
are more dilated than usual, allowing more light in.


(I'll admit to having yielded to the temptation to look in such
situations,
especially when there were naked-eye sunspot groups visible... but only in
brief glances, never looking steadily.)

So, build a shadow box. An old shoe-box works great. I keep mine around
for eclipses. Should scale it up so I can watch sunspots.


--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |