|
Post by mikey cee on May 31, 2013 14:03:01 GMT -5
Just finished reading about Neil's positive comments about his new Asteria R30. I personally from the get go realize that no two lenses can ever be created identical not even AP's or Tec's. A very informative read and a very thorough anectdotal relating of his first impressions with the 5" F/12 ota. For me I find it rather difficult sometimes in trying to relate to others what I'm seeing with my own two eyes(bino's)when using my own 10" F/11 R30 lens. But thanks to Neil he's put into words about 90%+ of what I've been seeing thru my lens. I'm not a technical person but I've observed enough planetary and double star images over the years to know that what this lens is capable of. When I observed Altair(my first light) and later split 72 Pegasi near the zenith last year I knew that this lens was something more special than even my old and faithful 30+ year old 8" F/13.3 R.E. Brandt objective. This was no small fete considering that the collimation was never really corrected until with a red dot lazer and cheshire eyepiece in just the last few months. Airy disc and diffraction rings couldn't get any better. Intra and extra focal images also show little to no errors to speak of considering the less than perfect seeing conditions about 98% of the time. Testing on the brighter stars with a ronchi eyepiece with a #58 green filter after several hours of cool down time shows nice straight vertical lines. Whether 3 big thick ones or a dozen thinner ones....beautiful!! Thank's Neil for putting into words exactly the quality I'm experiencing with my Istar lens! Mike
|
|
|
Post by kevinbarker on Jun 1, 2013 0:47:03 GMT -5
Just finished reading about Neil's positive comments about his new Asteria R30. I personally from the get go realize that no two lenses can ever be created identical not even AP's or Tec's. A very informative read and a very thorough anectdotal relating of his first impressions with the 5" F/12 ota. For me I find it rather difficult sometimes in trying to relate to others what I'm seeing with my own two eyes(bino's)when using my own 10" F/11 R30 lens. But thanks to Neil he's put into words about 90%+ of what I've been seeing thru my lens. I'm not a technical person but I've observed enough planetary and double star images over the years to know that what this lens is capable of. When I observed Altair(my first light) and later split 72 Pegasi near the zenith last year I knew that this lens was something more special than even my old and faithful 30+ year old 8" F/13.3 R.E. Brandt objective. This was no small fete considering that the collimation was never really corrected until with a red dot lazer and cheshire eyepiece in just the last few months. Airy disc and diffraction rings couldn't get any better. Intra and extra focal images also show little to no errors to speak of considering the less than perfect seeing conditions about 98% of the time. Testing on the brighter stars with a ronchi eyepiece with a #58 green filter after several hours of cool down time shows nice straight vertical lines. Whether 3 big thick ones or a dozen thinner ones....beautiful!! Thank's Neil for putting into words exactly the quality I'm experiencing with my Istar lens! Mike Mike I have also found and read the Neil English review. It sounds like a nice telescope and the review is very favourable about the build and quality of the scope he purchased. Meanwhile I am waiting for news about a 180 mm f-8 lens I have bought off Istar. I ordered this lens 5-6 months ago. I emailed three weeks ago and was given an assurance the lens would be tested etc and ready for shipping by the end of May. I was told 9 big lenses have been made. I wonder how other buyers are getting on with respect to updates. Perhaps they can post there information here. Kevin Barker
|
|
paulci
Junior Member
Posts: 20
|
Post by paulci on Jun 1, 2013 4:16:29 GMT -5
Hi Kevin, I'm one of the big lenses customers eagerly waiting for my 8" F12 R35. I too had the email from Ales a few weeks ago predicting around the 22 may that the lenses would be arriving with Mike harden in the states before checking etc. So I guess it should not be too long before we will be getting a communication in respect to dispatch times. I'm aware that Ales is out on his travels at present but hoping for an update soon!
Look forward to your build details and experience with the 180 once tested.
Regards Paul
|
|
|
Post by kevinbarker on Jun 1, 2013 5:57:30 GMT -5
Hi Kevin, I'm one of the big lenses customers eagerly waiting for my 8" F12 R35. I too had the email from Ales a few weeks ago predicting around the 22 may that the lenses would be arriving with Mike harden in the states before checking etc. So I guess it should not be too long before we will be getting a communication in respect to dispatch times. I'm aware that Ales is out on his travels at present but hoping for an update soon! Look forward to your build details and experience with the 180 once tested. Regards Paul Thanks Paul It is an interesting article written by Neil English. I was contacted by Neil a year or so ago when he was writing a book about refractors. I was really busy with work at the time and forgot to reply. He was asking me about Zeiss gear, Neil seems to be a refractor buff as many of us are who are using or hopefully about to use Istar scopes and optics. I will be relieved to finally receive the istar lens and if it is up to the 1/6 wave P-V Neil reports then I will be very pleased indeed. Neil speaks of the correction being better at shorter wavelengths and the advantages of this for double star work. I am still weighing up what sort of ota I might use, I am tempted to try a plyscope and have sketched plans for a hexagon although I may even consider other options. The inspiration here is the scope Andy jackson made which was detailed in the cloudy nights refractor forum. The skills that guy has are pretty impressive. I might have to tap a cabinet maker friend on the shoulder for the finer detail if i try this approach. Regards Kevin
|
|
paulci
Junior Member
Posts: 20
|
Post by paulci on Jun 1, 2013 9:08:39 GMT -5
Hi Kevin, Here's the link to my first refractor build. A hexagon constructed box around a 5" F10 henry Wildey doublet. Named "Wildey Rocket" stargazerslounge.com/topic/47552-wildey-rocket-refractor/page__hl__+wildey%20+rocket#entry487998My 8" Istar build will hopefully be a 12 sided version from high quality dark wood marine ply 1/4" thick. However if the weight becomes an issue after weighing the components then I may cut a big corner and try out one of Ales TCR rigs. Regards Paul
|
|
|
Post by kevinbarker on Jun 1, 2013 15:15:12 GMT -5
Hi Kevin, Here's the link to my first refractor build. A hexagon constructed box around a 5" F10 henry Wildey doublet. Named "Wildey Rocket" stargazerslounge.com/topic/47552-wildey-rocket-refractor/page__hl__+wildey%20+rocket#entry487998My 8" Istar build will hopefully be a 12 sided version from high quality dark wood marine ply 1/4" thick. However if the weight becomes an issue after weighing the components then I may cut a big corner and try out one of Ales TCR rigs. Regards Paul Paul That scope looks exactly like the one i have sketched(albeit a larger lens and longer focal length). It looks beautiful and functional. I have found a source of marine ply here in Auckland and am thinking 6 mm. With thicker ply for the baffles. I might try an alt az wooden mount, although it might be a big big. Well done, I also have an old 8 inch parks mirrored scope which is in a sonotube, i made the cradle and base. The tube is not rigid enough, it moves too much when handled and struggles with maintaining collimation. So what you have done with your 8 inch reflector is a great idea. Part of my problem with the sonotube ota is the mirror cell is very basic. I have yet to hear a review from a user of a TCR scope. Are there any out there yet? Kevin
|
|
gord
Full Member
Posts: 82
|
Post by gord on Jun 2, 2013 11:15:25 GMT -5
Amusing stuff indeed. The world Neil lives in is... interesting. He seems to have a dislike of all things apochromatic. And he apparently the phrase "low hanging fruit" is lost on him as well. He certainly writes a lot, but I don't feel says very much. Very "artistic" style. It seems that Canadians are having issues with IStar quality. I can only think of one Esprit 150 myself, but I didn't realize that owner wasn't able to receive a working IStar triplet either. Interesting... but Neil seems to have limited sympathy for apo-lovers! But on to more important things. It's worth pointing out the common mistake he made in trying to do a technical test to evaluate the correction. He's admitted he's not strong on the technical side and this is something that is commonly mis-understood. Mike, this applies to your comments on testing above as well. Refractors are designed to be best corrected in green light. As such, they need to be tested around that wavelength. This is often over simplified in forums to mean "put in a green wratten filter" and test. Like the #58. However, this is not a accurate way to test. This is because the wratten filters are broad band and let all the colors through (at various amounts of transmission) instead of just the one (or limited) wavelength. I know this for a fact as I was using one (a 58) in combination with an ND filter in my Lunt solar wedge to reduce the brightness of the sun and the purple CA around the limb of the sun was still present and still purple. The proper way to test is with a green light source like an LED or laser. This of course would be in a lab environment. The alternate is to use the Baader Solar Continuum filter. It's the only commonly available filter that will give you the isolated green wavelength (that I'm aware of). And Mike, as we've talked about on here before, the ronchi test you did is not sensitive enough to tell you anything other than if there are any gross optical errors present (reversed lens, very bad correction, etc.). You are only testing single pass remember, and this also has to be done with the same filter mentioned above. I know you have been reading the CN ATM forum and Jim Egger's progress on his 9.25". This has been talked about plenty there. Unfortunately also, Jupiter and Mars are not well placed currently so Neil is not able to test those. Those are the tests that have been identified as where the largest source of performance problems are to be for these IStar R-series designs. Clear skies,
|
|
|
Post by mikey cee on Jun 2, 2013 17:55:59 GMT -5
Gord I wasn't attempting a double pass test with a narrow band green source. I simply was using what I had at my disposal to cut down on the multicolored scatter around the airy disc caused by the seeing. It's easier to observe my disc and rings seeing permitting of course with a single green color that was all I was after. I know that the ronchi eyepiece test is not as accurate but it would let me know if something was way out there in left field. We have tested other scopes my observing friends have and use and believe me there have been some grossly bowed lines both over and under corrections. Some of those smaller 70mm, 80mm and 102mm refractors and short FL ones especially have severe cases of SA!! Not much good with the C5's or the C8's either. I've always been a firm believer in star testing as the ultimate definer of quality optics. My first planet was Mars and it was way easier to see detail with this Istar than with my 8" Brandt and that scope had a bigger Mars to study. Then it was Jupiter next and the detail overall was still better than the 8" I had used all those years. Of course the GRS is nowhere near as contrasty as it was back in those years so on those occassions it's not a fair comparison....but those blue festoons are what sold me over the Brandt. Sure we're comparing apples to oranges with seeing conditions being never identical and all. But if I'm satisfied I'm satisfied. I can't help it if this isn't good enough for others...that's their burden to carry not mine. Mike
|
|
gord
Full Member
Posts: 82
|
Post by gord on Jun 2, 2013 20:28:05 GMT -5
Hey Mike,
I may have asked you this before (but can't remember the answer); what ever happened to your Brandt? Did you keep it?
Clear skies, -Gord
|
|
|
Post by bn1777 on Jun 9, 2013 18:20:55 GMT -5
I am another that has seen Neil's review , and it mirrors my thoughts on my Istar lense . As most will know I have a 127mm f8 Achro and the images that shows on Jupiter , mars and Saturn are just so good . Double stars are a sight to behold , two perfect aeiry discs with a faint ring that comes and goes with the seeing , just beautiful . CA is not an issue to me but its very well supressed in this lense , I can only imagine what an 127 f8 of f12 R30 would do might be a job for me this next wet season . A good friend of mine up here in Darwin has a very nice 150mm SW f8 and last Saturday night we did a head to head , his SW and my Istar and the 127mm blew the 150 away on all objects , bar the 150mm going deeper so yes 25mm is a lot in this size and it shows the quality of the views my Istar throws up , very , very good ! . The SW owner was very impressed . On a final note on comparo's a club member here has a TV 127mm non 'is' I think ? , but him and I have discussed doing a comparo between his APO ( take note Gord ) and my achro , I am looking forward to that and I am not bothered that my scope cost $630 and his is like $6300 here in Australia ,, I will let you all know the out come of that when it is done and post the results here first . Yes a great review Neil and thank you . I only hope it helps perspective Istar owners to take the leap as I guarantee they wont be disappointed . One last thing , I apreaciate your imput Gord on this , but I don't think Neil bashes APO's as such , I think he like most of us don't have a spare $5000 + sitting around to get a 4-6 inch , when a sweet Istar accro R30 scope does it for most . Like it seem's to have done for Neil . Brian.
|
|
gord
Full Member
Posts: 82
|
Post by gord on Jun 13, 2013 20:56:35 GMT -5
Hey Brian,
Seems we are having the conversation across two boards! I won't repeat all I've just posted over there.
On your last comment about the price of apo's, let me be clear. That's a *lot* of money to spend on such a small scope (the larger apo's). Yeah, if I had it and could do it, then sure I'd be in that camp too! But I just can't justify it.
But where my comment on Neil's seemingly strong dislike of anything shorter and especially apo-chromatic is that there are many choices that are both ED/apo and very good value. Better even than the IStar R30's (in both value and especially performance), yet he doesn't seem to consider them worthy.
But, it's his personal preference as to what he likes for himself. YMMV.
Clear skies! -Gord
|
|
|
Post by bn1777 on Jun 14, 2013 6:06:35 GMT -5
Me to Gord , but I have looked thru many generic chinese 100-150mm achros and ED's and they all done their job very well for the price , but the little extra I am prepared to pay for an Istar lense is well worth it in my eyes . As you know the chinese ( Synta , HYO and others) is a bit of a lucky dip in quality control , where as Istars lenses and OTA's are hand figured and built , you are guaranteed a top quality bit of gear for the price with 100% satisifaction and a personal touch . If you want to spend 10k on a Takanashi 150mm APO OTA. then go for it , its a free world .
I am more than happy with my 127mm achromat Gord as you probably already know and if and when I grab a 127mm f8 R30 I wont worry if its not up to a middle of the road quality in its views I don't expect APO like CA correction it cant be had for $665 , that's a fact ! , but if it is better than my achromat and its gonna have to be very , very good to beat it , I see it as money well spent .
My Istar is way better than any generic achromat I have ever looked thru , and that's a fact, as well , Sire .
Oh yes it was a free world last I looked and I have sung Istars praises in "Sing astro ( James Ling's place) " , "Star gazers Lounge" , "Ice in Space" , "Astronomy Forums" and others , lots of positive feed back there . The only one I have not is Astro Mart , I was a 'green' supporter with a life membership up till last year when they changed the rules and wanted a yearly sub. my $750 went down the drain ,, not happy about that !!! With that dead money I could have had a 127mm f8 R30 with post and a little change for a few cold beer's ,, yea not happy !!!
But more than happy with my 127mm achro , its only curiosity that's compelling me to look hard at the R30's and it will happen .
Brian.
|
|
|
Post by Mike on Jun 25, 2013 12:41:09 GMT -5
"Better even than the IStar R30's (in both value and especially performance)"
Gord, you do not know this for a fact. You have no experience (scope time) what so ever with an R30 to make this statement. I accept any and all your criticism based on your personal experience or independent test results. If criticism based on hearsay from the "know it alls" over at CN are repeated on this forum by you or anyone else then this discussion is a waste of time and proves vindictive. I know this is not your intention and you are a bigger man than this so please do not make this mistake again. Agreed my friend?
Mike
Please tell me you didn't make this same statement over on CN... I can't find your recent conversation with Brian.
|
|
gord
Full Member
Posts: 82
|
Post by gord on Jun 25, 2013 14:20:00 GMT -5
Hi Mike,
I agree with you, I do not know it for fact. I haven't used one personally and there are no independent tests. What I'm basing the claim of better performance on is from the performance statements you guys are making of 30% improved performance.
As I pointed out on the other thread, expressing things as a percentage like that can be unclear. But I think you would have to agree that taking any achromat of similar size to the Synta 120ED and even making it have half (50%) of the color defocus as it would have normally, it will still show much more color error than the Synta 120ED's.
To expand on my "value and performance" statement, IMHO value is composed of many factors, but performance plays into it as well and outside of the just absolute performance criteria I mentioned. Two scopes costing the same amount and being similarly equipped, but one have significantly better performance, well, that one (to me) is a better value.
But I think this is great that we are having a discussion about the value proposition you guys are bringing forward and making it clear what it is! And also just to be clear, saying one this has better value doesn't mean that the alternative has no value.
Clear skies, -Gord
|
|
|
Post by Mike on Jun 25, 2013 17:24:35 GMT -5
I can understand and agree or disagree about the perception of value. I cannot agree with rating or commenting on performance from statements made. If this is to be productive, we need to play by fair rules.
|
|