Re: [ATM] Exit pulil and brightnees

["Bob May" <rmay@nethere.com>]

Look at it this way.
The telescope magnifies the image you are seeing.  What it is
doing is actually reducing the diameter of the ray bundle by the
magnification value.  Thus the size of the scope of 200mm gets
reduced to 2mm at 100 power.  The 5mm iris will accept all of the
light from the telescpe, thus not making the brightness of the
image any less.  However, when the magnification is less, lets
say we're at 10 power, the exit pupil will be 10mm.  At this
size, all will vignette the light with the smaller pupil seeing
less of the light than the person with the larger pupil.
The edge of the FOV isn't interfered with any differently as the
EP puts all of the light in the same area at the correct position
for viewing (when you barely see the field stop of the EP) so all
persons will see the same falloff of light the same amount.
Any more questions on this???
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net


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