Re: Lenses Are On Order

[aah@nofs.navy.mil]

Ron had an interesting point regarding the windows and filters, which I also
should have seen.  The filters are obviously going to be somewhere internal
to the front element (who wants to buy 4" glass filters?), and you do have
to worry about strongly converging beams doing things like moving the
filter bandpass, or getting close enough to the focal plane that the filter
dust gets into focus.  Probably these concerns are not warranted, but Elliot
might put the flats into the design just to be sure.  Like Ron, I'm not an
optical designer and I may be way out in left field.
  The 14-site mark IV concept sounds good to me.  I estimated that I could
cover the entire northern sky 2-3x/year from Flagstaff, so if 6 such sites
in both the northern and southern hemisphere are in place, then we can do a
pretty good job of determining magnitudes/colors for the entire sky, with
lots of support in looking for variables and other interesting objects.
  I just hit star 100,000 in my local CCD re-reduction, so I'm into the same
ballpark as the current mark III database (each of my 'stars' consists of
4-5 filters and many such sets per star).  It gives me more appreciation for
both the size of the mark III task and the upcoming mark IV.  Good thing the
mark IV survey won't happen for another year, as it will give cheap
computing a chance to catch up!
Arne