Dear IIS team,
The unit Lewis is referring to has been sold to myself.
I will be holding onto it long term, it is a very nice telescope.
PS: Technical - the FCT100 is a Canon Optron, Japan manufactured lens with an air spaced design with a 640mm focal length.
It is as all Tak refractors are a standard air spaced design, this one being an air spaced triplet, very similar in design to many triplets today (such as the Canon Optron triplet lenses used by Vixen & Sky Rover).
The FCT100 also includes a Fluorite lens element as the central lens element. It also uses Canon's premium manufacturing processes enabling a very capable optic, this unit is much better than any of the other Taks I have owned. It also uses Canon's class leading multi coatings, which are exceptional, as good as available commercially globally today.
This FCT100 optic I took to Carl Zeiss Germany when I visited them last year and had tested - it enabled a Strehl of 0.95, the highest Strehl the head of the Metrology Department at Zeiss has achieved in a Tak in his 35 years with Zeiss
Takahashi never made oil spaced refractors. Takahashi have always and only ever used Canon lenses - and Canon do not do any oiled's.
On to oiled's : Oiled's have higher resolution that aired's, optical physics demands this.
Are there are oiled's available today, Yes :
1. Carl Zeiss (used 2nd hand) - they always cost a lot, but they are much more than merely exceptional, they beat everything in their aperture class in performance. You should expect a price for a good condition APQ100 oil spaced fluorite triplet of around the $14k at today's costings plus import costs (appreciating in the future as they always have since manufactured). You need to see through an APQ to appreciate what an APQ is, those that haven't do not know what they are missing, seriously, there is no comparison. Many guess, and many talk about APQ's - not trying to upset you here guys - but if you haven't seen through an APQ you are unable to comment as you haven't achieved the summit of Everest and do not "know" the view
OR
2. CFF : today you have
one bespoke hand crafting manufacturer - this is CFF - who currently manufacture fully oiled triplets. The Aust distributor delivered a brand new CFF 160mm f6.5 to a keen enthusiast in Perth last week, a hand crafted fully oiled - test certified Strehl 0.992, same as my CFF 140mm f6.5 also test certified 0.992, and also same as my Carl Zeiss APQ100 test certified 0.992, these are all documented test certified optics. Yes test certified "real" documented certification.
OR
3. TEC USA do one (only) model which is "semi" oiled, between one pair of lens elements, not both. IMHO this is not a design I would personally pursue from my decades in optometrical metrology - if you are doing an oiled you do the whole thing oiled, or leave it at the less costly and much easier to manufacture air spaced. IMHO it's a bit like getting in a car, you do not stop with the door open, you either get in or you don't.
TEC (and most telescope manufacturers) do not have test certification available. They do not have access to the necessary test equipment, same as Takahashi. Where you see quoted TEC, Tak, TeleVue, AP and many others quoting Strehl's these are not test certified and should be viewed with extreme caution as they are not measurements and are often guesses or sellers trying to keep up with offers from those that actually do have the test equipment - as example the test equipment at Officina Stellare was an investment of many hundreds of thousands of EUR. Those that do have tested certified optics usually have telescopes on offer with much greater quality, thereby justifying the investment in the metrology system with which to measure their optics. There are only a few manufacturers that have/ have access to test certification, they are the only test data that should be trusted, as everything else is heresay.