Don't get me wrong. The DF/DC/DL are excellent scopes. I haven't had the DZ, so I can't comment on that.
Though I wouldn't wright off the FS-102 as some folks here do. Look through one, do a side by side test if you can, on Jupiter/Saturn or Mars, then let us know what you think.
...there will be no remarkable difference - same for the FL-102S... btw.
All those discussions about color-correction are academic - if you want to see differences lay those apos on an optical bench and do a startest at 400x in doublepass - then you see real differences but not really under the night sky...
Much more important for me would be weight, size, robustness, back-focus, focusser-travel, collimateable lenscell... - maybe spherical correction of each sample where I never saw a REAL bad one within 3x FL, 2x FS, 1xDC, 2xFC(old) and my most liked fluorit doublet is a FS-128 btw. that with some luck one can get for the price of a new DL or DZ
It never lusted me to much for a better color corrected 4" fluorit doublet because I have one of the best color corrected fluorit triplets - an f/10 105mm oil filled Astro Optik Manufaktur apo and even the differences to that one are not really worth mentioning compared to my Tasco FL-102S.
...on the other side... go, go buy some more DZ´s - so somewhere in future we can get some for a low price on the used market when Tak releases their next one
Edited by donadani, 04 April 2020 - 04:29 AM.