|
I just checked the review and yes you are right it is an air spaced triplet.
I read a post by Roland Christen about air spaced triplets versus oiled triplets.
He basically said that air spaced is harder to make (6 glass to air surfaces each requiring exacting work) but it allowed the optician more degrees of freedom for colour correction. For example the AP160 is an air spaced triplet whereas AP scopes are usually oil spaced triplets (as are TEC scope). So again the emphasis would be on the optician's skill.
If a TSA 120 is around the US$4500 area I would go a 2nd hand TEC140, that's an extra 20mm of aperture, it is light and I have yet to hear of anyone who has owned one who was less than rave review happy with it. You often see them on Astromart for around US$4500 and they come with rings. I can let you know if one comes up.
Its not really a question of is the Tak TSA120 better than the TEC140 as both are excellent and aperture rules so the bigger one is usually the better. A 140mm scope is really an ideal size in many ways for both visual and imaging.
It is the AP scope that you can actually get.
Greg.
|