Older Eypiece Design

I have recently brought a number of EP's that date from the 1980's including circle-v and circle-t Ortho's in 9, 12.5 and 18mm, a 25mm Kellner and a 32mm Erfle. All these are 1.25 inch.

Up til now I have got used to using modern Plossl's of various FL's but now I have tried the older EP's I'm not entirely sure now that newer is always the best.

Although the older EP's have smaller fields of view in the main and I guess the coatings are not as efficient as modern designs, it seems to me that they are simply nicer to use in some ways. For one thing the conical tops lift the eye lens up to the eye whereas the modern plossls have flat or even slightly dish shaped (ie: shorter FL Ultimas) tops so you seem to have to search for the eye lens.

Another factor for me is that the lesser fields of view (often 45 rather than 50 degrees) are easlier to view without pushing your eye right up to the lens and seem (to me at any rate) to put less demand on the eye.

I guess that my f10 refractor is less demanding than short FL scopes which might struggle with the older EP's but does anyone else think that some of these older EP's have some advantages over the newer designs ?.

John,
England

Quality is quality, and blah is blah. (Flair for the obvious, eh?)

Fact is, many of the low-cost brand-new (or "no-brand" new) standard eyepieces (i.e. Kellners & Plossls) are just not very well executed -- regardless of their inherent potential. I'll take a fine Kellner over a ho-hum symmetrical Plossl or Abbe every time.

The only time I *don't* like the 1.25-inch cone-top design is when eye relief is ~15mm or more. In my case, that viewing position places my eye too far rearward -- result being, I can actually see *around* the body of the eyepiece itself (the cone-top doesn't quite fill my eye's field of view, and there's a little "leakage" at the perimeter). Of course, this is easily remedied with an eye cup (I use "donuts" of pipe insulation foam, which serves double duty as a superb dew-preventer). When shorter eye relief is encountered, yes, the cone-top design better "fits" the recessed structure of the human eye socket.

On the other hand, my eye socket absolutely *loves* the fit and "feel" of my 18mm Meade Superwide's cupped/dished top.

Best wishes.
-Dan

I certainly like the eye relief on shorter fl Orthos than that of same fl Plossls. (e.g 9 and 12.5) Somewhere in the mid-teen focal lengths, I start to like the Plossls. And with less glass than "premium" eyepieces, I understand that Orthos are as sharp as they get. The only downside is that reduced FOV, and if you are not tracking you want that as big as it can get.

Charlie