Tune-up your eyes for optimal nighttime viewing!
02/07/07 10:11 Filed in: Observing
I normally wear glasses purely for
close-up work and optical testing, but just recently I found that
the slight astigmatism in my eyes was getting annoying enough to
need spectacles for distant work too. This set me thinking about an
article my old Sky & Telescope colleague, Joshua Roth, wrote in
the September 2005 issue. Entitled 'Spectacles for Spectacular Skies', the article
explains why your optician's prescription for distant viewing may
not be optimal for stargazing. I discovered that I suffer from
night myopia - a tendency to become a bit near-sighted in the dark.
To cut a long story short, I had a pair of anti-reflection-treated
glasses made up for me by an online store with lenses that were 0.5 dioptre
weaker than my daytime distant prescription. The result:
spectacularly sharp nighttime views!

