Thanks, James, for the vision test site. Groovy stuff.
I'm probably re-inventing the wheel in a big way here, but I used the blind
spot the other night while observing.
There was a bright field star that was making it hard to see a faint galaxy
- probably in Virgo, but I'd have to check my log. (And this particular log
is a microcassette that won't get transcribed until who knows when...)
Knowing roughly where my blind spot is, and using the right eyepiece and
scope aim point, I made the bright star disappear, while putting the galaxy
in an area of averted vision. Very handy!
The main limit on this is that the blind spot is basically off to the left
or right of your eye's "central aim point" (the fovea?), so the position
angle of the dim object relative to the bright one could be a dealbreaker,
unless you could rotate the field (or your head) somehow.
pauses, goes outside briefly...
Okay, I just made the moon disappear while looking directly at Jupiter. The
angular separation between them tonight is such that by closing one eye and
putting my eyes in the plane of the ecliptic, the moon went away. Neat!
Someday, I'll have to try and see how many naked-eye objects I can see at
Full Moon - and this trick might help.
--- Marek Cichanski