-----------------------------------

Gabriel Muranca

03 Dec 2009 17:22



-----------------------------------

Nu vreau sa fiu inteles gresit ca iau parte unui tip de instrument sau altul. Doar vreau sa scoatem in evidenta care este domeniul in care un instrument exceleaza si in ce conditii.

Uitati si parerea de pe un site, zic eu, in care se trateaza problemele serios:
"Much has been said about the  effect of central obstruction in the amateurs circles, most of it being speculation. The common notion is that it reduces effective linear aperture for low-contrast details by as much as obstruction diameter. Informal attempts have been made to find a theoretical basis for this empirical "rule". Not a few amateurs "tested" it and often concluded that it "works". What tends to be neglected is a pretty obvious fact that in any such comparison there is more than just a single factor - central obstruction - affecting low-contrast performance. Most of these factors - seeing error, overall optical quality, sensitivity to miscollimation and thermal errors, light scatter, baffling - favor smaller unobstructed aperture, usually a high-quality apochromatic refractor, over the larger reflector or catadioptric."
http://www.telescope-optics.net/obstruction.htm