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Home > Forums > ASTRONOMY EQUIPMENT > Refractors > Message #552394

Re: C102F can't come to focus

Posted by Roland Christen on 10/18/2007 8:34 AM in response to Re: C102F can't come to focus   (1042 hits)
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>>"This was one of the first fluorites sold.>>

I can tell you a bit more of the history of this scope. I met Mike Simmons back in 1982 at the Riverside Telescope conference. Mike was the designer of the Edmund Astroscan and the Simak and Astromak, and designed the first GoTo systems for Celestron and Meade.

Mike had done some design work for Celestron, and suggested to them a fluorite doublet using CaF2 and ZKN7 to produce a totally color-free 102mmF8 doublet. I saw the prototype of this scope and the views through this lens was awesome. Zero color on any object, including Venus and Sirius - just like a mirror. He suggested that Celestron work with the Japanese to produce this lens in 4", 5" and 6" versions. At the time, Celestron was working with Vixen, and they were eager to compete with Takahashi and basically out-do them. Unfortunately the Chairman at Vixen was more interested in producing small scopes for kids at reasonable prices, so the design was modified. The expensive ZKN7 design was ditched in favor of using KzFN2 glass, which produced some color error, but was much easier and cheaper to produce. Vixen's chairman felt that the market for a kid's telescope was larger than that for dedicated amateurs, so he never pursued the higher end of the market. He did not care at all about imaging, thus the scope came with 1.25" hardware, and only later was a 2" back added so you could attach a 35mm camera.

The lens, of course was made for Vixen by Canon's Optron division, same place that was making the Tak lenses. The fact that the Vixen was F9 allowed it to have somewhat better correction than the 100mm F8 Tak lenses, and many amateurs in Japan felt that it was a better overall lens than the Tak FC100.

Rolando

Thread:

Subject Posted By Date/Time Hits 
C102F can't come to focus Evan Chan 10/16/2007 8:55 PM 872
Re: C102F can't come to focus John Biretta 10/16/2007 10:15 PM 615
Re: C102F can't come to focus Evan Chan 10/16/2007 10:34 PM 552
Re: C102F can't come to focus John Biretta 10/16/2007 11:39 PM 499
Re: C102F can't come to focus Oren Soffer 10/16/2007 10:16 PM 536
Re: C102F can't come to focus Oren Soffer 10/16/2007 10:24 PM 485
Re: C102F can't come to focus Evan Chan 10/16/2007 10:33 PM 468
Re: C102F can't come to focus Oren Soffer 10/17/2007 1:16 PM 414
Re: C102F can't come to focus Evan Chan 10/17/2007 2:30 PM 435
Re: C102F can't come to focus Floyd Blue 10/17/2007 3:14 PM 533
Re: C102F can't come to focus Evan Chan 10/17/2007 5:21 PM 381
Re: C102F can't come to focus Oren Soffer 10/17/2007 3:27 PM 371
Re: C102F can't come to focus Philip Blanda 10/18/2007 7:03 AM 354
Re: C102F can't come to focus Philip Blanda 10/17/2007 6:55 AM 392
Re: C102F can't come to focus Chase McNiss 10/17/2007 6:34 PM 380
Re: C102F can't come to focus larry thaxton 10/17/2007 8:54 PM 481
Re: C102F can't come to focus Roland Christen 10/18/2007 8:34 AM 1042
Re: C102F can't come to focus Paul Leuba 10/19/2007 12:19 PM 551
Re: C102F can't come to focus Paul Leuba 10/19/2007 12:24 PM 439
Re: C102F can't come to focus Evan Chan 10/19/2007 1:15 PM 377
Re: C102F can't come to focus Paul Leuba 10/19/2007 4:40 PM 377
Re: C102F can't come to focus Evan Chan 10/19/2007 4:53 PM 330
Re: C102F can't come to focus Paul Leuba 10/21/2007 1:57 PM 338
Re: C102F can't come to focus Roland Christen 10/19/2007 2:34 PM 590
Re: C102F can't come to focus larry thaxton 10/20/2007 10:04 AM 440
Re: C102F can't come to focus Evan Chan 10/20/2007 10:46 AM 316
Re: C102F can't come to focus Paul Leuba 10/21/2007 2:14 PM 326
Re: C102F can't come to focus John Powers 2/27/2008 4:59 PM 266
Re: C102F can't come to focus Jake Jacobson 10/18/2007 10:09 AM 339
Re: C102F can't come to focus Evan Chan 10/18/2007 10:18 AM 331
Re: C102F can't come to focus Jake Jacobson 10/18/2007 11:34 AM 328
Re: C102F can't come to focus Jake Jacobson 10/21/2007 10:08 AM 328
Re: C102F can't come to focus James Siska 10/18/2007 10:46 AM 395

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