On 2/29/2012 we (MJR, JMB and CD) measured the input cone of EXES. We used the tip of a 700F soldering iron as a probe, and moved the iron along a piece of graph paper located 25.75" in front of the window (22" from front of the flange to the graph paper; the flange ring is 4.125" inches in width, and the back surface of the lens penetrates 0.375" into the flange ring: 22 +/- 0.25 + 4.125 - 0.375 = 25.75")
We used the 4.7um filter and the 1.5 km/s slit, and acquired continuously, watching the flux graph as the soldering iron top was moved along the graph paper.
[The proper orientation to scan along the slit was established by procedure X.]
We watched the flux graph and marked the position of the soldering iron tip when the flux was at half maximum.
The total width between half-maxima was 6.2 graph squares or (0.25"/graph square)*6.2=1.55"
Therefore, the half-angle of acceptance is:
arctan(1.55/2/25.75)= 1.724 deg= 0.30088 rad
==> 0.002844 Steradians
Error guess forthcoming...
Subscribe to:
Post Comments (Atom)
1 comment:
Using the optics+zemax, I get that the internal focus is roughly 5.125" in from the back of the lens. That would make the half angle 1.55 / 2 / ( 25.75+5.125) = 0.0251 radians.
Post a Comment