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Post by Mike on Aug 26, 2011 9:50:07 GMT -5
The lens you are inquiring about has been designed already. Getting a blank of the material to achieve R60 is the problem. Not only is it outrageously expensive, due to a recent triple price hike of that material, it takes a long time to get it. I have a 250mm R30 in my possession now. I believe it was ordered in January or February of this year. That is too long. Not to mention the risk involved if after a long wait for the blank, weeks of grinding and polishing, then testing and finding out you have giant paperweight. Fortunately, this hasn’t happened to us. Istar refuses to be that company you have to wait forever for your order. We are sticking to the product we can deliver in a reasonable amount of time. I will talk to production about the 300mm just for kicks and let you know what they say.
Mike
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Post by Watcher3 on Aug 26, 2011 19:11:39 GMT -5
Is it still less expensive than common ED glasses? (FPL51 and the like)
Also. while you're asking, maybe you can find out how the common EDs compare to the lanthanums, as far as color correction. Would a scope made with EDx be better corrected than one made with lanthanum, for a specific focal length?
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Post by mrkellytaylor on Aug 28, 2011 3:49:20 GMT -5
One way or another I will own a 12 inch 300mm or 305 mm F/12 to F/10 Refractor Doublet of some kind I am not bothered by a little color My 204 mm F/8.8 Does just fine and my 6 inch F/15 also works fine for me. I will be pulling the trigger on Parallax HD 200 Mount GOTO Soon then 12 inch refractor here I come. feel free to send private emails. Got the Big Glass fever now that I am retired got time to look. Mr. Kelly Taylor
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Post by Ales - iStar Optical on Aug 29, 2011 3:12:08 GMT -5
I would like to know if a 300 mm R65 is possibile simple doublet F/10 3000mm Mr .Kelly Taylor, we have designed several R60 lenses using two exotic glass types BUT the cost seem to be much more than what we have previously anticipated. The Lanthanum Flint has gone up by 320 percent since January 2011!!! So now, we have for example 150mm doublet which cost 2400 US dollars retail.. as I said.. MUCH more than anticipated, you may as well get an APO triplet in 160 F12 for less than 3000... so at this point we are not sure if we should continue investing time and money into the R60 doublets, need some feedback from customers on this. Again, price for 150mm doublet is now set at 2375 dollars with no chance of getting a less expensive glass. Lanthanum has gone up world-wide and we are still getting good price per kilo of this material. But this "good" price is over 3x more compared to end of last year... cheers, Ales
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Post by mrkellytaylor on Aug 29, 2011 19:03:50 GMT -5
Well even if i have to get a Crown Flint I am Still looking at 300 mm F10 3000mm. I guess when they found out you could make a good refractor with that glass it went up. 320 percent is just crazy. $7,000.00 to $12,000 is my price range for lens in cell and Counter Cell. I want some thing in 254mm to 305mm Mr. Taylor
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Post by Mike on Aug 29, 2011 22:06:38 GMT -5
Mr. Taylor, I emailed you direct.
Mike
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