TOA 150 claims, could this be?

I did some looking around for figures on the TOA 150 for a discussion on another site and came across a description of the TOA 150 in another dealer's ad copy. I have a TOA 150 and I'm right happy with it but I wasn't aware it was performing at this level.

"Orthoscopic means perfected visually and Apochromatic means you're free from those strange violet glows which often accompany bright stars or planets. Thanks to the ingenious design of layering an FPL-53 Extra-low Dispersion glass element between two extreme quality crown and flint elements - perfection ensues. And what's more, it's air spaced, so there's no oil between the elements to leak or become opaque with age. The lens cells are durably constructed to withstand transport - yet are fully able to be collimated should the owner wish to make adjustments. With 1/12th wave accuracy and an airy-disc Strehl ratio of 0.992, the optics on the Takahashi TOA-150F Ortho-APO are as near to perfection as you can get!"

If a Tak Mewlon gives "refractor like performance", than I always wondered what their refractors did. Now I know :-) Maybe I should change my oil in my oil spaced triplets every 7000 light years so it doesn't color? I hope the new super duper refractor performs "Mewlon like". Martin

I thought that the TOA design was two FPL-53 ED elements surrounding another, non-ED, piece of optical glass with one of the air gaps being a large one. This inaccuracy (if inaccurate it is) would tend to cast doubt on anything else that might be claimed in the ad copy especially if no other source (TNR) repeats it.

Philip

Jerry Wise said: ... ingenious design of layering an FPL-53 Extra-low Dispersion glass element between two extreme quality crown and flint elements

Jerry Wise said:

"Orthoscopic means perfected visually and Apochromatic means you're free from those strange violet glows which often accompany bright stars or planets. Thanks to the ingenious design of layering an FPL-53 Extra-low Dispersion glass element between two extreme quality crown and flint elements - perfection ensues. And what's more, it's air spaced, so there's no oil between the elements to leak or become opaque with age. The lens cells are durably constructed to withstand transport - yet are fully able to be collimated should the owner wish to make adjustments. With 1/12th wave accuracy and an airy-disc Strehl ratio of 0.992, the optics on the Takahashi TOA-150F Ortho-APO are as near to perfection as you can get!"

I have no first hand knowledge of the design other then samples of the telescope that I have compared to my FS152. But it sounds like OPT is quoting theoretical correction. As is often done in ad copy, the marketing guys will quote the best case theoretical correction spit out by Zemax or Oslo if the design is executed flawlessly. In practice, the design is NEVER executed perfectly. There are too many variables, outside of the opticians control like glass melt, coatings etc. Variations in glass melt can be dealt with by hand figuring, but I am not sure TAK does this.

The TOA's I have seen at Cherry Springs, are really color free with a huge air gap. However, I don't believe they are corrected to a 1/12 wave.