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Post by Watcher3 on Apr 14, 2011 18:08:07 GMT -5
James Ling posted over on CN, mentioning an R75 lens that Ales had told him about. He also mentioned a projected price of about $1000.00. Well, I had been expecting that my R50 lens was going to be about that price, so I contacted Ales. Seems that while experimenting with different glass types, they came up with something that works better than their planned R50 for about the same cost! They will be making the R75 INSTEAD of the R50. I'm getting much better than I expected.
Bill P over at CN really put it into perspective for me. The R50, he said would have about the same color correction as a 6" F/10. The R75 should equal a 6" F/20! I know a lot of people can be bothered the color even in some pretty nice ED refractors, but to my eye, this is going to be an APO. I think I'm gonna have to get a Powermate for my 6mm Ethos!
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Post by jamesling1000 on Apr 14, 2011 21:03:23 GMT -5
Yes. Joe is correct. Beside Joe already confirm his order for this 150 R75, I am also being invited to be one of the few to have the 1st batch of new 150 R75. For me, if I made the official reservation to ISTAR, I'll have to go for the OTA, coz I really don't have time to build one myself, with the lens cell.
Ales, also told me that for the 160 triplet APO, using Lanthanum, they have to produce min. F/9. I have the celestron C6R F8, and I can also consider to use the tube and add on an attachment to his lens cell.
Again , anyone who is keen and interested in the size and type of lens cell, is good to put it down in this forum, so that everyone can share the information, and is also good for ISTAR.
Regards
James Ling
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Post by Watcher3 on Apr 15, 2011 10:54:06 GMT -5
I'm happy that you will be getting the OTA James. I really want to go a different way with my scope, but I was considering the OTA just so I could get an evaluation of this new lens on the internet sooner. My build will take a while, as I need to have some parts machined for me, and the rest, well this will be my first real design and build. I will feel much better knowing that you will be able to report on it's performance soon after delivery. I think this lens is going to be an instant classic.
Clear skies Joe
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Post by istarmullet on Apr 15, 2011 11:28:14 GMT -5
Would you guys mind educating me on what the "R" refers to when you are discussing these ED lenses?
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Post by Watcher3 on Apr 15, 2011 13:58:49 GMT -5
As far as I know, it is just a designation for "R"educed CA. 30% and 75% respectively, compared to the classical achro.
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Post by jamesling1000 on Apr 19, 2011 23:50:05 GMT -5
Hi All....
I have written email to Ales, and got his reply on both the latest development of the 150 F5 R70 and the Lanthanum glass issue that being debated in the cloudy nights forum.
1. 150 F5 R70
YES ISTAR is going to offer Lanthanum doublets under R70 since they were able to achieve 70 percent CA and spot size reduction using Lanthanum together with another rare glass. So our order for the first 150 F5 R70 which will use Lanthanum glass.
2. Lanthanum glass.
Ales says that Lanthanum glass is one of the most stable glass types on the market with rating 1 3 1 3 meaning VERY good, for example against humidity and water resistance 1 that is BEST you can get, resistance against acids 3 that is GOOD, resistance against other chemicals 1 that is EXCELLENT, actually best you can get.. etc..
Lanthanum is one of the best optical glass types used in most better and top end camera lenses, top end eyepieces AND Istar lenses. This glass has been redesigned a number of times during past 40+ years and the version we use is the latest version which can (if combined with other more expensive glass types) be used to create a great APO triplets and semi apo doublets in R70 range.
REgards
James Ling
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Post by Watcher3 on Apr 20, 2011 11:51:28 GMT -5
Thank you James. Good info. It's hard to keep up with ISTAR! They're moving pretty fast! Joe
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Post by Mike on Apr 20, 2011 13:50:42 GMT -5
James, you beat me to it! I got the same email from Ales. Joe and I were trying to squash the false statements being made on CN refractor group, which incidently went well over 2000 views. Poor Ales is trying to answer a barrage of email concerning the Lanthanum glass. You know what they say though, " any publicity is good publicity (or somethng like that)." Ales could really use some orders though. He said the last couple of months have been bad. I keep telling him to get me that scope ASAP so I can out a review
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