Re: ATM POSITIVE RELAY LENS AND OSLO LT.

[Bratislav Curcic <epabcc@epa.ericsson.se>]

Kurt Sidor wrote :

>  According to 1.22*lamda*F#=airy radius, my airy disk of
> the original image would have a diameter of 0.010mm.

Wrong. The size of diffraction disk of an f/4 scope is 5.4 microns
(0.0054mm). At f/16 is is 21.5 microns. Wavelength of light is really
550 nm (0.00055mm), not 0.001mm.
By the way, did you use just one color ? You should dial in all colors
from C to F for visual use and C to h for photographic. Add IR to about
1100nm if you plan to use CCD. Basically, you want all the rays inside
Airy disc for d line, and have maybe 1.5 to 3 times the Airy at C and F
for reasonable chromatic performance (similar to excellent 6" f/15
achromat).  For CCD use you can't afford that luxury - any rays 'out'
will be visible as blurred image.

> From using the program and by adjusting the lenses location to provide
> the 4X relay to get the image out of the diameter of the incoming light
> I found that the lens I chose of 15mm dia is actually too big!

At f/16 light dropoff is really fast. So unlike f/4 where one can get
away with zero size of 100% illumination and still have small
vignetting even in corners of 35mm film (20mm away from axis), at f/16
you will hit zero illumination only millimeters from your 100% area.
If you want to see whole Moon (1/2 degree) you'll need 100% field to
cover at least 20 arc minutes.

Bratislav