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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   (1380 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 951
Re: C102F can't come to focus John Biretta 10/16/2007 10:15 PM 664
Re: C102F can't come to focus Evan Chan 10/16/2007 10:34 PM 627
Re: C102F can't come to focus John Biretta 10/16/2007 11:39 PM 557
Re: C102F can't come to focus Oren Soffer 10/16/2007 10:16 PM 602
Re: C102F can't come to focus Oren Soffer 10/16/2007 10:24 PM 531
Re: C102F can't come to focus Evan Chan 10/16/2007 10:33 PM 504
Re: C102F can't come to focus Oren Soffer 10/17/2007 1:16 PM 466
Re: C102F can't come to focus Evan Chan 10/17/2007 2:30 PM 486
Re: C102F can't come to focus Floyd Blue 10/17/2007 3:14 PM 575
Re: C102F can't come to focus Evan Chan 10/17/2007 5:21 PM 419
Re: C102F can't come to focus Oren Soffer 10/17/2007 3:27 PM 411
Re: C102F can't come to focus Philip Blanda 10/18/2007 7:03 AM 397
Re: C102F can't come to focus Philip Blanda 10/17/2007 6:55 AM 436
Re: C102F can't come to focus Chase McNiss 10/17/2007 6:34 PM 451
Re: C102F can't come to focus Larry Thaxton 10/17/2007 8:54 PM 572
Re: C102F can't come to focus Roland Christen 10/18/2007 8:34 AM 1380
Re: C102F can't come to focus Paul Leuba 10/19/2007 12:19 PM 635
Re: C102F can't come to focus Paul Leuba 10/19/2007 12:24 PM 485
Re: C102F can't come to focus Evan Chan 10/19/2007 1:15 PM 442
Re: C102F can't come to focus Paul Leuba 10/19/2007 4:40 PM 445
Re: C102F can't come to focus Evan Chan 10/19/2007 4:53 PM 392
Re: C102F can't come to focus Paul Leuba 10/21/2007 1:57 PM 383
Re: C102F can't come to focus Roland Christen 10/19/2007 2:34 PM 645
Re: C102F can't come to focus Larry Thaxton 10/20/2007 10:04 AM 496
Re: C102F can't come to focus Evan Chan 10/20/2007 10:46 AM 349
Re: C102F can't come to focus Paul Leuba 10/21/2007 2:14 PM 365
Re: C102F can't come to focus John Powers 2/27/2008 4:59 PM 320
Re: C102F can't come to focus Jake Jacobson 10/18/2007 10:09 AM 390
Re: C102F can't come to focus Evan Chan 10/18/2007 10:18 AM 368
Re: C102F can't come to focus Jake Jacobson 10/18/2007 11:34 AM 386
Re: C102F can't come to focus Jake Jacobson 10/21/2007 10:08 AM 367
Re: C102F can't come to focus James Siska 10/18/2007 10:46 AM 453

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