Re: Turbulence and diaphragm

On Tue, 2 Jan 2007 12:04:58 +0100, "giorgio mengoli"
<gmengoli1@xxxxxxxx> wrote:

Hi all,
Someone has direct experiences or documentations or you draws that speak of the technique of
diaphragm of the telescope amateur to contain, at least partly, the effects
negative of the seeing?

See:
http://www.csastro.org/gallery/article4.htm

In my experience an apodizing screen can be useful in masking the
negative effects caused by a Newtonian primary mirror that has a poor
edge; but as for improving the effects of poor atmospheric seeing when
one is using a telescope with high quality optics -- in my opinion an
apodizing screen is all but useless!

I once built and used such a screen (I still have it somewhere!). It
seemed to work until I painted over the outermost 2-3 millimeters of
the Newtonian primary mirror. After the painting, the scope performed
better *without* the screen!
--
Bill
Celestial Journeys
http://cejour.blogspot.com
.