David Nakamoto wrote:

Perhaps we can get someone from Lowell Observatory or Stewart observatories,
the former in Flagstaff and the latter in Tucson, to answer this, although I
wonder how definitive the answer would be. It seems to me that this is
another area of human knowledge where DEFINING what you mean by adaptive and
active would clarify what the situation is immensely.

As for my two cents . . .

I don't know what is meant by "active." Is tracking an object automatically
active? Is changing the optics to "correct" for something active?

Adaptive to me means a method by which the optics can be changed to reduce
or eliminate seeing effects. By this definition, and by the fact that
SBIG's tilt-mirror system reduces low frequency "waves" seeing, it is an
adaptive system.

I was one of Steward Observatory's first three people working on the MMT
active optics. The goal was active focus and alignment of the outer 6
telescopes with respect to central (guide/alignment) telescope. We were
to do this with less than 10E-12 watts of laser power out of the
guide/alignment telescope. I left the project in 1974 I think but the
concept was complete then.

Chuck
--
... The times have been,
That, when the brains were out,
the man would die. ... Macbeth
Chuck Simmons