Re: 1/6 or 1/8 wave


"Dennis Woos" <dpwoos@xxxxxxxxx> wrote in message
news:12qf60edbasro16@xxxxxxxxxxxxxxxxxxxxx
I have a poster from AstroQuest that shows a similar comparison through
an
8" scope, with additional comparisons of various secondary obstructions.
I've done a fair of observing with good 8" and 10" scopes, and I don't
think
either the web site or the poster quite convey the amount of detail that
can
be seen under steady skies.

Clear skies, Alan


I agree with you about the amount of detail shown, but I also find it hard
to directly compare detail in an image and detail seen through an
eyepiece,
especially as I have been accused of having "averted imagination" by the
more visually challenged members of our club. As an aside, these sceptics
recently clamored for an eye doctor who was a guest speaker at a club
meeting to give me a contrast sensitivity test that he had with him. To
their chagrin, I scored higher than anyone else and above the "normal"
range, and even a bit better than my older teenage son who I know has
somewhat better visual acuity.

I would get the best optics I could afford, period. I have found that
superior optics are a pleasure to observe with, and are less susceptible
to
bad-seeing/bad-collimation/bad-cooldown/bad-eyepieces/bad-karma problems.

Dennis,

Interesting. I think time behind the eyepiece can greatly improve our
visual abilities.

I agree that fine optics are a joy, and provide some real advantages, but
once you get to about 1/6 wavefront PTV (1/30 wavefront RMS) you'll be doing
pretty darn well. In larger optics I suspect very few instruments are
performing at this level, both because of the difficulty in making such
optics and properly supporting them.

Clear skies, Alan

.