I owned an Astro-Physics 155 F 7 for 17-years but not at the same time as my Mewlon 210. The Mewlon 210 actually replaced my AP155 when I downsized.
First: The amount of fussiness of the Mewlon 210 (and all Cassegrains) depends on where you live. If you live in a southern, very mild climate, acclimation and cooling are minimized. And if you live in an area with above average seeing, you can take advantage of the Melon’s aperture more often.
I happen to live in PA so I need to be aggressive with cooling and I only use the Mewlon 210 when the seeing looks to be at least a little above average, otherwise I use my Tak 120.
If we are strictly talking about the moon (which is mostly a high contrast object), I think the Mewlon 210 (when acclimated) will, at the least, equal a TEC 160 on detail and maybe deliver just a hair more.
On the planets (which are low contrast objects) I would give the TEC 160 the nod. As good as the Mewlon’s contrast and sharpness is, it is not as good as a high-end refractor.
The big advantage of the refractor is its ability to deliver the goods in just average seeing or even slightly below average seeing and the stability of the view in falling temperatures. Refractors are just less fussy. That’s why my Mewlon 210 is not my only telescope. With the Mewlon 210, it’s nice to have a high-end refractor on hand for nights when you want to go out but conditions are more challenging. Where the high-end TEC 160 could easily be an only telescope.
If you don’t care about fussiness etc. the Mewlon 210 will absolutely deliver the goods and not disappoint. Price and portability also favor the Mewlon 210. If coming on-line quicker and use in somewhat more challenging seeing conditions and the slightly better planetary views you can get (between the two scopes) is a top priority, and price and portability are non issues the TEC 160 would be the choice.
Edited by bobhen, 06 December 2018 - 08:03 AM.