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Home > Forums > VENDORS > Chinese Optics Imports > Message #568084

Re: CHINESE MADE 152MM APO IN CELL

Posted by John Biretta on 1/5/2008 1:23 AM in response to Re: CHINESE MADE 152MM APO IN CELL   (1152 hits)
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The plot showing the longitudinal errors looks
superb -- much superior to typical triplet lenses.
It seems to be a quadruplet with 2 ED elements!?

It is less clear to me what to make of the
specification "Surface Accuracy (not worse) ?/4
at 632.8nm." I assume they mean lambda/4.
With 8 surfaces that amounts to 2*lambda surface
accuracy. Since it is refractive glass, the
wavefront accuracy is about 1/3 of the surface
accuracy, or about 2/3 * lambda. But this is
a very poor quality specification. Perhaps it is not
what they meant to say? If it is lambda/4
on the **wavefront** at 632.8nm then it would
be acceptable quality or at least "diffraction
limited."

The link you give has inside of it another link
that indicates Intane Optical as the source:
http://www.intane-optics.com/products/apo-152mm-f-8-38-catalog-1.html
I am a little surprised Meade / William-Optics / BO
is not importing them if they are truly viable.

There is a review of an 80mm APO by this company
Intane on Cloudy Nights, it is the first scope in the review:
http://www.cloudynights.com/item.php?item_id=1706
Some quotes: "you have to wonder if the designers
have ever actually been near a working refractor ...
coma due to miscollimation was so horrid it was hard
to even make out best focus. It looked like the scope
suffered from severe astigmatism ... this unit was so bad,
and the problems so blindingly obvious...." Now most
of the problems were in the OTA tube, and they were never
able to completely test the lens, but the indications
are not good.

Sounds interesting, but I'll probably hang on to my
$3500 for now. If someone wants to buy one, I'll be
happy to test it.

This post was modified on 1/5/2008 1:55 AM

Thread:

Subject Posted By Date/Time Hits 
Re: CHINESE MADE 152MM APO IN CELL John Biretta 1/4/2008 4:06 PM 540
Re: CHINESE MADE 152MM APO IN CELL John Biretta 1/5/2008 1:23 AM 1152
Re: CHINESE MADE 152MM APO IN CELL John Biretta 1/5/2008 11:12 AM 621
Re: CHINESE MADE 152MM APO IN CELL Roland Christen 1/5/2008 9:31 AM 676
Re: CHINESE MADE 152MM APO IN CELL Floyd Blue 1/5/2008 10:29 AM 522
Re: CHINESE MADE 152MM APO IN CELL Donald Durbin 1/4/2008 4:38 PM 513
Re: CHINESE MADE 152MM APO IN CELL George Mavromates 1/24/2008 10:32 AM 469

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