Don Mickey (mickey@ahinahina)
Wed, 17 Feb 1999 19:36:50 -1000
The good news is that retarder B actually works. I believe someone
failed to reconnect a cable properly, at least a couple of times.
The other good news is that retarder B (the new one) scatters much less
light than the old one. I think that if we mention scattering and
retarders in the same sentence we should point this out. Choices for
flight hardware shouldn't be based on 10-yr old information.
The other good news is that looking down the maw of the IVM with the
alinment telescope works, and the reflection from the entrance window
is bright enough to set the infinity focus, and the reflection from
the FP appears nice & bright, perfectly centered in the field stop
and in focus.
The other good news (well, sort of, but I'm on a roll) is that I'm pretty
sure the vignetting we've been seeing at the top of the data image
is caused by that weird baffle attached to the front of retarder A. I
took it off, we'll see if that leads to bad stray light. Shouldn't, I think.
I tweaked up the spar balance a bit, it's good enough to work.
----Don Mickey <mickey@ahinahina.ifa.hawaii.edu>