... and still the best wife I could wish for!
Hypotheses non fingo
C14 XLT, CGE NexSTAR 11 GPS + 120ST APM/TMB 130/780, AT111EDT SW EQ5P (2" Tripod/20" Pier) XW's 3.5mm - 20mm, 28mm RG, TVZ 2-4 ES14mm/20mm 100° UWAN 28mm,Paragon 40mm, TV55, Meade 2X 2" TeleXtender TMB SMC 4mm-16mm, Pentax 0-18, CZJ 0-25 EarthWin PFS-DBSE, WO DuraBright, AP MaxBright TV Bino's Bino Sets X 2: UO H.D's ~ 5mm-18mm, TV Pl.(NJ's)7.4mm - 40mm 16T5's, 24mm Pans Canon 18X50 IS Pentax 7X35 (9.3°
Quote:Gord, I've only owned a handful from you list, but I have a few questions?How come the Istar R-Series is last when It's supposed to be better than a standard Achro? My understanding is the R30 or R60 is reflected in the Focal Length, so an 6" F8 R30 would perform more like a 6" F10.4.
Quote:Is the APM 6" Chinese Doublet the one Markus just released?I would think the APM 6" Russion Doublet would be closer to the 6" Flourite Doublet, but not sure.
Quote:Also, where would you fit in the hugely popular 120ED?
Quote:For me personally, CA nullifies most of the detail due to It's presence, but everyone's differnce.I've also noticed that when some (but not all) ED Doublets are pushed to a high magnification the Image starts to "yellow" in tint. Again, to me this is bothersome, but a personal thing.
Scopes: 190mm SW Mak-Newt @ f/5.3 & 90mm SV Raptor Triplet @ f/7Cameras: Atik 383L+ mono w/ EFW2 FW with Astrodon filters & Canon XSi 450D (Modded)Mount: Astro-Physics Mach1GTO mount guided with QHY5 KWIQ guiderSoftware: Sequence Generator Pro; PixInsight; Photoshop CS5Best investment: Stone Garden Observatory - Bortle 4 (Green)
Leica 8x20; Nikon Action 7x35; Vixen Apex Pro 8x42; Orion 15x63; Docter Nobilem 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet
Quote:Hello everyone,Just a quick note to put some things straight. R30 and R35 doublets from Istar are NOT normal standard achromats only with color shift designed to let red hang out.. this is a totally wrong assumption and theory, created by who known whoom... I exaplained true facts about this design on numerous ocassions. The shifting of the color sensitivity is only one of many advantages of R30 and R35 designs. We use a special glass types like short flints to achieve this improved performance which falls within the Halb Apochromat standards. To achieve a greatly enhanced resolution while decreasing the spot size and substantially lowering the level of chromatic aberrationSince can not be done by tweaking the design for one color or another. We use much more expensive glass types compared to what is used in classic achromats, and this is how you get the inhanced performance. So obviously we must charge more for the more expensive lens. I hope this explains a bit.. I suggest that before anyone posts another piece of info about R30 doublet, they should look thru one and compare to any standard achromatic doublet. Happy New Year to everyone!!! cheers,Ales
7x35 and 10x50 sears tower binocs, 3" f/10 edmunds reflector, 2.4" f/11.7 manon refractor, 6" f/8 jaegers refractor, 10" f/11 R30 Istar refractor, 3" f/15.8 sans&streiffe refractor, 3.1" f/15 selsi refractor(towa 339), 2.4" f/15 sears refractor, selsi 30x30mm spyglass, criterion 5-draw 25x45x75x spyglass(1957), 4.25" f/14.8 tasco 20te.http://cleardarksky.com/c/OmahaNEkey.html
Quote:Hi Gord. I believe we have a larger problem here of communicating our anectdotal experiences at the eyepiece. I don't doubt for a second that we have here some trade offs but it's awfully hard to qualify them accurately. Take for instance my comments about comparing my 8" Brandt to my 10" Istar. You must remember that when using my 8" over the last 30 years that the GRS was noticeably a deeper red than it is today. Heck it really faded a few years back as the SEB nearly vanished completely. Also with the exception of that one night of detecting albedo features on Ganymede I haven't really had any knockout good seeing. That night the super good seeing was short lived and the GRS was not visible at that time. Also the GRS now is more of a pinkish orange color. How's that for making up a color shade? I believe seeing plays a much larger role than optics or a person's individual eyesight compared to another's. You really need to have the scopes side by side to come to any meaningful conclusions here. Otherwise it just makes for fun conversation and speculation and not much else. I'm very satisfied with my lens and I feel that when some good seeing comes it will "knock my socks off" most assuredly. Oh and another thing that in telling these recollections at the eyepiece this lens is still in the process of acclimating to current temps and at any given moment I have no idea how far along it is in the "cooling" process. Most nights I close up shop well before the lens ever reaches total equilibrium I'm sure. Mike
Backyard + Observatory + Blue Zone = Heaven
Istar 127 f12 R30 & Tak FS78 on a DSC G11
VSO - C8 XLT and Stellarvue F80M2 on DSC GEM
Solar - Lunt 60THa B1200 on Vixen Super Polaris
Zeiss, Fujinon, Istar
Quote: Oh Mike,Forgot to ask you... what do you feel about the 6" F8 achro with and w/o the Chromacor relative to your triplet in terms of Jupiter performance? Again, more data-points.
Quote:the new one's that APM has. In their case, they are a little different still than the IStar's since they both use ED glass as well. The Chinese one uses the older LaF glass, while I think the Russian one is using something like the FPL-53 glass. Because they use ED glass, they are better corrected to start with than an achromat.However, they apparently are tuned as well to focus on reducing the traditional false color as well. Since they are starting out ahead of the achromat to begin with, they don't have as far to go, so aren't going to be as affected. But it's still not going to be as ideal (again for our Jupiter example) as a normally corrected ED.
Quote:A quick note to the discussion on the refractor forum regards correction of our chinese and LZOS 152 doublet ED. both are not designed to reduce purple and increase red spotts. Both are correct designed, optimized for visual observations, tthe classic tradional metthod !!!!!!!!!!!!!
Quote:Here's a reply from Markus, who as you know is no longer allowed to post in this forum, so he posted this in the vendors forum:Quote:A quick note to the discussion on the refractor forum regards correction of our chinese and LZOS 152 doublet ED. both are not designed to reduce purple and increase red spotts. Both are correct designed, optimized for visual observations, tthe classic tradional metthod !!!!!!!!!!!!!Comments anybody?
Quote:Recently on the Istar scope club Ales K ( an part owner of istar) has released spot diagrams of 6 different 150 mm doublets and triplets. The red spot sizes are larger but not hugely larger than the blue spot sizes. Although the actual wavelength versus focus sketches are missing.
Quote:I chiefly observe in seeing that is typically 6-8/10. The suggestion a scope can show the detail of the 10 inch processed pic continuously put forward surprises me.
Quote:ValeryWas it a well controlled fair test ? Same observer, night, eyepiece, mag, aperture etc on same object.Or is what you are talking(comparison of four 5 inch refractors) about just an impression.Kevin
How close am I on this?
Quote: Gord, the Chromacor can be "fiddly", but once adjusted properly It does work! In my C6R w/o the CC, I would never turn the scope to Jupiter as It's just a purple mess!With the CC however the purple is gone and the Image is very much Improved, however the AT111EDT is still in a league of It's own. The detail and contrast of the Triplet is just amazing. I'm not sure If It's the glass used or ??? but the AT111EDT puts up a super rich view (contrast?) of Jupiter that I haven't seen in many other scopes. It's similar to the effect the TV Plossls have on Jupiter as well.Also, as a side note, This past summer, A friend and I (Tank) were viewing with his RFT 6" F5 Refractor and decided to see how the CC would do with the newer "red shifted glass" (on Vega).Answer......amazing! w/o the CC, Vega was a mess with the CA extending to about the size of a Full Moon (viewed with naked eye). With the CC in place (no spacing), The CA was reduced to a size maybe 2X or 3X the size of the Star. An amount similar to what's seen in the older (Semi) Apo Triplets, or ED scopes. And this was a 6" F5 scope, so I'm sure the F5.9 or F6.5 version would fare better.
Quote:Thanks for sharing this piece of info.
Quote: In your opinion, where do you think a Chromacor equipped achro would fit? Or, based on what you were describing in terms of different scopes, do you think it could fit at many levels in the list based on how close of "fit" it is to the scope, and/or it's individual setup in the scope?I've heard the comments about the need to be precise with the setup before and plenty of negative comments if it is off, and positive ones where it is on. So it seems like it's likely something like the latter I describe. I wonder where it could theoretically be at it's best?It would be good to hear from more users.
Quote:I can add one important thing: the optical designers in a past knew the optics and human eye work not any bit worser than todays designers. And I think they knew optics better. All fundamental investigations in this field were done at that old good times. All classical telescopes were designed by masters and be sure, they experimented with different designs and chooses which work best.
Quote:I guess I don't understand all the fuss going on here about a designers choice in balancing out the red and blue spot sizes.
Quote:I looked at spot diagram of TSA-102. http://www.takahashi-europe.com/en/TSA-102.optics.spots.htm TSA-102 has much tighter focus on the blue end but FS-102 is much tighter on the red end.Does it mean FS-102 is really that much better on Jupiter or Mars?I both owned FS-102 and TSA-102 but the answer was no for my case even though the view was so close.
Quote:BTW Mike, when you used your Chromacor on the 6" F5, you were probably stopping down the aperture slightly with the nose of the Chromacor. Your color correction improvement may have been, in part, due to the stop down.
Quote:Gord you say "Again, there is no perfect design, so it makes sense if they aren't as good at planetary, they may be very well suited to something else."It seems you have convinced yourself to this end. (the istar R30 design does not perform as well as an C F corrected achromat on planets) based on spot diagrams.You have however not seen through an R30 scope with your own eyes and in fact are making assumptions based on what a vendor has said before about other scopes.This (Valery's insinuation directed at the R30 Istar scopes) reminds me a bit of Newton dismissing Cassegrain's scope design a few centuries ago.I think his thread is unfair in this respect to 2 vendors (Istar and APM). They are being dismissed theoretically without any concrete evidence.No one has done a comparison with an istar R30 and a similar C F achromat.I guess at least folks are not still claiming they use the same glass as normal F2 BAK 7 fraunhofer achromats.Casting dispersions can be unfair when they are not supported by hard facts.Kevin Barker
Matt in Oz Takahashi Mewlon 210 F11.5 = 2415mm Takahashi TSA120 F7.5 (out on loan) = 900mm Takahashi FC76CSV F7.5 = 570m Takahashi FS60CB F5.9 = 355mm
Quote:Jeff, Do you think (from the Diagrams) that Markus's APM 150mm F8 ED (Chinese) Refractor would be better, equal, or worse than a C6R/CC1?Mike