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Post by bn1777 on May 16, 2014 20:32:08 GMT -5
Ok , where to start ? I suppose if you all go to 'Ice in Space' and open 'Astronomy Forums' scroll down to 'Equipment' and open 'Equipment Discussions' and you will find a thread titled 'United Optics'. These are a locally designed refractor and the 130mm triplet is the scope in question here . This scope along with its smaller siblings , the 102 and 115 are 'Fluorite' , from Japan sandwiched between 2 'Shott' elements from Germany , nice !. Its the 115mm f800mm triplet that's the scope that's the scope in question here and yes it is a true Fluorite as a green laser shone down the objective shows the inner and outer lens's but the middle fluorite is invisible , a gap that looks like there is nothing in there , nice , just like my Takahashi . I spent last night under good seeing conditions doing a head to head with my SKY90 , and doing a through seating of this scope , read the IIS thread for info . The owner of this awesome triplet , yes it is the best 100-120mm APO I have ever looked thru , beating out a WO 110mm triplet owned by another observing buddy here and that's no easy feat !! . Anyway I suggested we do a Luna only side by side with his 115mm f6.9 APO and my 127 f8 Istar doublet as my Istar easily bested the WO 110mm APO on fine Luna seeing , yes there is a very dark purple seen in the Achro , but its so benign its not a worry to me ,,, he he , MY scope ! . Stay tuned as this will happen in about 16 days weather permitting , we will be viewing the 5-9 day old moon using my TV eyepieces and 2x Powermate allowing up to 533x in the 115mm and 666x ( ouch ! ) in the Istar ... let the fun begin . Brian.
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Post by astromanuk on May 17, 2014 1:59:53 GMT -5
Brian,
Looking forward to seeing how you rate the United Optics. There is no doubt that the Chinese optical industry has come on in leaps and bounds in the last few years alone. Western orders with high quality specification has no doubt fuelled this. Why, even the venerable Zeiss have moved some of their manufacturing to China.
Here we have a great example of global manufacturing at its best. High design specification coupled with globally sourced raw materials (such as the Schott glass and possibly Japanese fluoride element). Manufactured in a country where a plentiful labour market can pick and train a competent work force to build at a budget price. This will not always be the case. We are already seeing Labour costs rise in China as the workforce becomes consumers of their own brands. The only thing still in need of attention is quality control which is still hit and miss.
What really sets Istar apart is the quality delivered at a price point. Strict quality control at each stage of manufacture and assembly then final testing before dispatch to the customer. It really does not matter where components are manufactured these days as long as the design, specification and QC are controlled at all stages of manufacture. This is something a few of the big guys could take a lesson from Istar on.
Looking forward to hearing of your exploits. I am not a gambling man but if I were my money would be on the Istar for resolution and overall image quality. But it may be close.
Good luck!
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Post by boomboom on May 18, 2014 18:24:04 GMT -5
Good stuff Brian! just made reference to the IIS thread on Mikes why not post thread. Just bought an ES 8.8mm 82º eyepiece that is brilliant, unlike a previous one I had a couple of years ago that was slightly fuzzy…hit and miss as Ian says. Matt
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Post by bn1777 on May 19, 2014 6:38:20 GMT -5
Ha ha jut commented on it , have a look I am glad you have grabbed a nice ES 8.8 these get good reviews , this will give awesome high power views of the moon and planets with ease in the 152mm ? nice mate .
Brian.
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Post by bn1777 on Jun 3, 2014 3:58:14 GMT -5
Weather permitting the shoot-out is going to be this Friday night using the 7-8 day old moon , we are both excited about this ,,, stay tuned people .
Brian.
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Post by bn1777 on Jun 6, 2014 22:38:38 GMT -5
Have to shoot out shortly to a Rum tasting afternoon ,, mmmm? so here is a teaser from last night . The weather was nice and clear , but the seeing was scintelating wildly , but we had a good time comparing both scopes for 4 hours or so . More will follow. Here they are ... Brian. Attachments:
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Post by bn1777 on Jun 6, 2014 22:45:23 GMT -5
The optics. Attachments:
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Post by Ales - iStar Optical on Jun 8, 2014 21:53:23 GMT -5
Have to shoot out shortly to a Run tasting afternoon ,, mmmm? so here is a teaser from last night . The weather was nice and clear , but the seeing was scintelating wildly , but we had a good time comparing both scopes for 4 hours or so . More will follow. Here they are ... Brian. Brian, I'm really interested to hear about how did the iStar 127 f8 standard achromatic doublet tested out in a direct competition with a full-blooded APO triplet. And I hope that I'm not the only one here on ISC. Regards, Ales
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Post by bn1777 on Jun 9, 2014 5:55:07 GMT -5
Thanks for your interest Ales , no-one else seems very interested at all Anyway mate the 127mm did a very good job on Friday night , the 115mm APO owner was vey impressed to say the least ! . The Istar showed a little CA , but it showed more inricate detail along the terminator up to the max of 300x in the iStar and 280x in the triplet , the atmosphere was really quite bad as seen in the photos of the moon shown here, there was a pronounced yellow tinge seen in both scopes that I have never seen before in the iStar and Brian ( yes another Brian ) had never seen before as well, you can see it easily in both moon shots. It was hard to get good clear photos due to the atmosphere and these are the best with either scope , as usual hand held Nokia Lumina 1020 hand held over the eyepieces. On that Brians APO with its 805mm fl using his 13mm Baader Hyperion giving 62x and my iStar with my TV Nagler 16mm giving 62x are what we wetre using when these shots were taken ,,really quite horrible !! I know but the seeing was quite bad ,, . After we packed up about 12pm Brian said over a coffee that he was really impressed with my 127mm achromats performance and said he can see no reason to spend 3.6k on his OTA when quality like mine can be had for $630 OTA build of mine , he was very impressed with all aspects of the achro's performance and cant wait for a better night to do this again , as I am as well . Here are the photos , Brians Triplet APO is the first 62x shot and my iStars 62x shot is second , yes the CA is there as is the yellow tinge , both are worse in these photos than seen with our eyes . HOPE THIS GETS SOME RESPONSES ..... Brian. Attachments:
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Post by boomboom on Jun 9, 2014 17:31:10 GMT -5
Well it's nice to see some awful night skies out west Brian!!!!! One day I'm going to stop my 6" down to 4" and compare with my 4" f9 ED Skywatcher scope. f18 achro v f9 ED…hmmm Nice conclusion that the APO owner came up with…totally agree I'm am biased though. Does the 17mm aperture difference have much effect on the view? It's been a month since I have had my scope out, looking like a long time til it's out again. Matt
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Post by Ales - iStar Optical on Jun 9, 2014 20:42:11 GMT -5
View AttachmentThanks for your interest Ales , no-one else seems very interested at all Anyway mate the 127mm did a very good job on Friday night , the 115mm APO owner was vey impressed to say the least ! . The Istar showed a little CA , but it showed more inricate detail along the terminator up to the max of 300x in the iStar and 280x in the triplet , the atmosphere was really quite bad as seen in the photos of the moon shown here, there was a pronounced yellow tinge seen in both scopes that I have never seen before in the iStar and Brian ( yes another Brian ) had never seen before as well, you can see it easily in both moon shots. It was hard to get good clear photos due to the atmosphere and these are the best with either scope , as usual hand held Nokia Lumina 1020 hand held over the eyepieces. On that Brians APO with its 805mm fl using his 13mm Baader Hyperion giving 62x and my iStar with my TV Nagler 16mm giving 62x are what we wetre using when these shots were taken ,,really quite horrible !! I know but the seeing was quite bad ,, . After we packed up about 12pm Brian said over a coffee that he was really impressed with my 127mm achromats performance and said he can see no reason to spend 3.6k on his OTA when quality like mine can be had for $630 OTA build of mine , he was very impressed with all aspects of the achro's performance and cant wait for a better night to do this again , as I am as well . Here are the photos , Brians Triplet APO is the first 62x shot and my iStars 62x shot is second , yes the CA is there as is the yellow tinge , both are worse in these photos than seen with our eyes . HOPE THIS GETS SOME RESPONSES ..... Brian. Dear Brian, Thank you very much for your response and some really encouraging test results proving that even a standard iStar achromat can perfom on top level. Something xperts like Neil English are trying to explain to general public for years. These days most people are simply obsessed with APO triplets and they ignore a simple fact, that a well designed achromat can deliver outstanding images of most night sky objects. Overall quality of deep sky objects is identical and if you can live with minimal amount of chromatic aberration, you will see same amount of detail on the Moon, Mars, Jupiter and Saturn. But I can not mention these facts on other forums, especially the Cloudy Nights without being ridiculed and attacked. Thanks God for having guys like you who are not afraid to say the simple truth about real life performance of achromatic doublets. And now with our latest generation of R35 and currently designed R45-S we are another step closer to an APO performance while remaining in achromat price range. After all, this was the whole purpose for designing and producing these special doublets. Definitely keep me and everyone else here posted about your next shoot out session. And let me know whenever you ready for a bigger lens. Best regards, Ales
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Post by boomboom on Jun 11, 2014 6:50:45 GMT -5
Ohh Ales, an R45….wow….an R 60+ any time in the future? ? Over in that 'other forum' there are a few too many 'legends in their own lunch time' as we like to say over here. Many times I read it over and over again….can't change the laws of physics….etc etc etc. The biggest thing rarely mentioned is the atmosphere as beautifully illustrated by Brian. The other thing missing, in all the really boring maths thats trotted, out is the human element. That's what I like, no love, about my Istar scope…the human element. Too many optical snobs out there. Long Live Istar Regards Matt
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Post by astromanuk on Jun 11, 2014 14:33:04 GMT -5
I Quite agree Matt.
Great observations and I would really like to compliment you on your objective approach to the testing. I am of the opinion that some observers are more sensitive to chromatic error than others. In my case I can work around it. The most important thing to me is the details I see in the image. My 4" f/15 refractor gives me lunar images with no noticeable colour error. I had a 5" f/5 that showed lots of colour on the moon so I didn't look at the moon with it - I used it for low power wide field star vistas at which it excelled.
It is for this reason that I am eagerly awaiting news of a larger Istar WFT. What these short focus refractors do so well is difficult to replicate in any other optical design. Add in the R45 prescription and the Istar team will be on to a winner.
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Post by Ales - iStar Optical on Jun 11, 2014 16:07:52 GMT -5
Ohh Ales, an R45….wow….an R 60+ any time in the future? ? Over in that 'other forum' there are a few too many 'legends in their own lunch time' as we like to say over here. Many times I read it over and over again….can't change the laws of physics….etc etc etc. The biggest thing rarely mentioned is the atmosphere as beautifully illustrated by Brian. The other thing missing, in all the really boring maths thats trotted, out is the human element. That's what I like, no love, about my Istar scope…the human element. Too many optical snobs out there. Long Live Istar Regards Matt Hello Matt, Well, the laws of physics can not be broken. With our current approach where we combine short Flint (LD glass) and standard Crown, the R45 is just about maximum we can reach. Yes, R60 is possible, but we would have to go into expensive Lanthanum glass. As you might already know this type of glass quadrupled in price couple years ago. Reason why we were forced to discontinue our R65 plans and our Lanthanum APOs. But we are working further on improving our optical designs and we have some good ideas currently in works. If we succeed solely depends on availability of glass we need. If all works out well we will have some really interesting products to show by end of this year and in 2015. Best regards, Ales
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Post by pchas01 on Jun 12, 2014 23:23:57 GMT -5
Thanks for the very nice report Brian, good info and excellent results. As far as the yellow tinge, as mentioned, some people 'can't see the forest because there are too many trees in the way'. They become fixated at the anomaly and don't see the big picture. What I would like to see is how the 150/5 or 204/6 perform on deep space objects when imaging. Unfortunately those are few and far between. A camera imaging DSOs really doesn't capture too much CA, except for some violet fringing on brighter stars. Even that can be tamed by filters or by using a couple more glass elements in the form of a reducer/corrector. A perfect example of that can be seen in the following image, which was taken with a Borg 50mm/f5 achromat (2 element) and a .85 reducer (2 element): Messier 33 w/50mm by Astronewb2011, on Flickr So, judging by that picture, an ota with three or more times the aperture would make an excellent imaging system for DSOs? Ales, the 150/6 or a 180/6 could be fitted with a Borg .65 4 element super-reducer for some mind boggling images... Best regards...Paul
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