So, I'm toying with the idea of getting a bigger refractor for weeknight use at home in Bortle 6-7 light polluted skies primarily for visual use viewing planets, double stars and the Moon. I have an FC100DL, which is excellent but I thought it might be nice to get something bigger.
I live in the Pacific Northwest where the weather changes rapidly, and is often cloudy with frequent sucker holes and warm days with cool nights and the jet stream is usually overhead.
I have an old C-8 and on a perfect night it can provide stunning views of the planets but it gives me endless headaches with cooling, dew and doesn't perform that well in mediocre seeing, which is all too common. I've set it up next to my DL several times and the DL almost always beats it by a large margin due to the C-8 having issues with cooling, dew and seeing. The only time the C-8 beat the DL was once in the middle of the summer on a warm steady night and the experience that one night left me wanting more aperture. I could try to mount fans on the C-8 or get one of the newer ones with active cooling but I don't really want to hassle with any of that during the week when I am tired from work and need some thing that "just works" for a a short impromptu session.
The DL on the other hand is always ready to go on a moment's notice if we have a break in the clouds, like a few days ago when I got nice views of Mars looking through a sucker hole that lasted less than an hour. The DL just works. That's what I am looking for only bigger, if that's possible.
I was leaning towards an APM 152 ED but then I read that they typically need 60 minutes or more of cooling. That won't work for me. I need something that will always be ready to go at a moment's notice and will perform well even in 2 arc-second seeing if that is what the conditions happen to be but will also be ready to knock my socks off if the seeing happens to be better.
I was almost ready to give up on the idea of a larger refractor after reading that other air spaced refractors in the 5-6 inch range like the Tak TSA-120 and the TOE 130/150 or the SW Esprit 150 all need 30-60 minutes or more of cooling for optimal viewing.
Then I saw this thread on the TEC 140 ED oil spaced triplet. From the description in that thread, the TEC 140 sounds like a larger FC100DL. What caught my eye in particular was the fast cooling of the oil spaced triplet design. Maybe the TEC 140 will perform like the FC100DL only with more aperture?
But the TEC 140 ED was replaced by the TEC 140 ED FL, with a middle florite element, which sounds good on paper but is considerably more money and from what I have read in this thread the new florite version performs no better and maybe even not quite as well for visual than the old TEC 140 ED since the TEC 140 ED was optimized for visual use but the new florite version is optimized for both visual and AP. So maybe I should look for a used TEC 140 ED?
None are available now but there is a used TEC 160 ED on astromart for what looks like a good price. Should I get the 160 ED? Its more aperture still but requires a beefier (more expensive) mount and will be more bulky for those rare times I may want to haul it to my dark site.
I've also read some good things about CFF scopes but there don't seem to be as many of those here in the US where I am located.
I'm still a ways from needing a new bigger refractor but I have been toying with the idea and thought I would put this out for discussion and advice.
Particularly I'm interested in advice about choosing between a TEC 140 and the 160, whether to get the florite version, whether to look at other brands of oil spaced triplets like CFF, or whether to just stick with my FC100DL and give up on the idea of a larger aperture refractor. Maybe the FC100DL is the perfect balance between fast cooling and planetary performance in a variety of seeing conditions?