ICEINSPACE
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Waning Gibbous 90.7%
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05-07-2018, 05:22 PM
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Registered User
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Join Date: Mar 2012
Location: Mornington Peninsula, Australia
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For a bit more wouldn't you go for the ts 130 f7 triplet?
https://www.teleskop-express.de/shop...A-focuser.html -
there is a more expensive one if you want a larger focuser.
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05-07-2018, 05:59 PM
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Join Date: Feb 2006
Location: Warragul, Vic
Posts: 4,493
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Quote:
Originally Posted by gregbradley
I have used a Tak FS152 before which was fluorite and crown glass element doublet. It was great visually but a bit false colour in images.
Greg.
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I wonder if it's a mistake for a fussy imager to try to make one scope do two jobs?
The NP127is might work though?
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05-07-2018, 06:38 PM
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Join Date: Jun 2013
Location: Lake Macquarie
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Quote:
Originally Posted by rustigsmed
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Well the question related to Doublets, not Triplets. It does not reflect my personal preference. As a personal preference, yes I would prefer the 130mm FPL-53 Triplet.
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05-07-2018, 06:43 PM
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Join Date: Feb 2006
Location: Sydney
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Quote:
Originally Posted by rustigsmed
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Sounds like a nice instrument. FPL53 air spaced triplets were a rare type of scope not that long ago.
How times have changed.
Greg.
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05-07-2018, 06:46 PM
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Join Date: Feb 2006
Location: Sydney
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Quote:
Originally Posted by rustigsmed
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Quote:
Originally Posted by casstony
I wonder if it's a mistake for a fussy imager to try to make one scope do two jobs?
The NP127is might work though?
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Petsvals as I understand them generally are not good for visual.
My TEC180FL was good at both visual and imaging so not necessarily. But if its a Petsval then yes its more oriented towards imaging and not visual.
I think I am more interested in an APO triplet and F7 with a nice reducer/flattener available.
Greg.
Greg.
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05-07-2018, 07:58 PM
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Join Date: Feb 2006
Location: Warragul, Vic
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Quote:
Originally Posted by gregbradley
Petsvals as I understand them generally are not good for visual.
Greg.
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In terms of planetary viewing the NP's are only marginally behind the Tak doublets and triplets and the NP is designed to be easy to use for visual.
The most noticeable difference between my NP101is and FC100d is depth of focus due to the focal ratio's and the FC is a little more contrasty I think (need to get them side by side on Jupiter again).
An NP127 is a lot pricier than a TS triplet though.
Here's an interesting review: http://doctordreviews.com/4inch-shootout.html
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07-07-2018, 08:00 AM
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Registered User
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Join Date: Feb 2006
Location: Sydney
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Quote:
Originally Posted by casstony
In terms of planetary viewing the NP's are only marginally behind the Tak doublets and triplets and the NP is designed to be easy to use for visual.
The most noticeable difference between my NP101is and FC100d is depth of focus due to the focal ratio's and the FC is a little more contrasty I think (need to get them side by side on Jupiter again).
An NP127 is a lot pricier than a TS triplet though.
Here's an interesting review: http://doctordreviews.com/4inch-shootout.html
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Thanks for that. I thought about a TV NP127i but to be honest I have not seen any spectacular images using that scope. Good ones but not top notch.
I suspect the correction is not as good as it needs to be these days to stand out. If China is putting out respectable air spaced FPL53 triplets for 1/3rd the APM LZOS price then the playing field has changed. Air spaced triplets were only done by TMB/LZOS up to a few years ago.
We also now have FPL 55 glass making its appearance. I am not sure how much better it is over FPL53, I suspect only a little.
Greg.
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07-07-2018, 08:14 AM
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Ultimate Noob
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Join Date: Aug 2011
Location: Melbourne
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From what I’ve read FPL-53 has a higher abbe number (closer to fluorite) but FPL-55 is easier to figure and possibly has better mating glasses.
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07-07-2018, 08:30 AM
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Quote:
Originally Posted by Atmos
From what I’ve read FPL-53 has a higher abbe number (closer to fluorite) but FPL-55 is easier to figure and possibly has better mating glasses.
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Yes almost identical Abbe number. Better grinding capability may end up meaning a higher strehl number for the optician to achieve.
Greg.
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07-07-2018, 08:33 AM
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Novichok test rabbit
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Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,388
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With hints at a possible Roland Christen retirement, the end of the GTX-130 line, and a SHORT run of the 92mm Stowaway, if you want anything touched by the hand of Rolando, I'd jump now (though you cannot get on EITHER waiting list as both are closed).
Otherwise, the Tak 120 is VERY hard to beat, except with the TOA 130 (which is, for all intents and purposes, perfect).
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07-07-2018, 08:37 AM
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Join Date: Feb 2006
Location: Sydney
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Quote:
Originally Posted by Atmos
From what I’ve read FPL-53 has a higher abbe number (closer to fluorite) but FPL-55 is easier to figure and possibly has better mating glasses.
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Quote:
Originally Posted by LewisM
With hints at a possible Roland Christen retirement, the end of the GTX-130 line, and a SHORT run of the 92mm Stowaway, if you want anything touched by the hand of Rolando, I'd jump now (though you cannot get on EITHER waiting list as both are closed).
Otherwise, the Tak 120 is VERY hard to beat, except with the TOA 130 (which is, for all intents and purposes, perfect).
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Yes I am on both of those lists. The AP 130GTX list I got on very early.
I can see those 2 Tak offerings are very nice. The TOA though is often said to be heavy and front heavy at that. Not sure if that is a real problem in use though. Too bad they don't do a TOA110. That would be nice.
The Tak 120 does sound nice. The offerings are odd though in that the TSA line is 102 and 120 and TOA is 130 and 150. I wonder if there is a reason for that other than marketing and a change of direction.
Greg.
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07-07-2018, 12:32 PM
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Novichok test rabbit
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Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,388
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TSA line is ONLY 120 now - the 102 has been out of production a few years now, replaced - oddly - with the FC-100 (not a wise Tak choice to cancel the 102 IMHO, as it was THE best 4" scope I have ever owned or used). I expect the FC-100 sells better, being considerably cheaper than the 102 ever was.
The design of the TSA is pure triplet, whereas the TOA is well-spaced triplet. The new fluorite FOA shares the same design principle, and is one of the highest Strehl production scopes ever made (it's for all intents and purposes a poly-Strehl of 0.995)
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07-07-2018, 12:46 PM
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Registered User
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Join Date: Oct 2004
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Its a shame Tak don't have a "F" version of the TSA-120 with the larger focuser like the TOA-130. For visual its fine but hate the TSA-120 focuser for imaging, tried a few electronic focusers like robofocus and nothing worked when I had the large STT-8300.
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07-07-2018, 12:58 PM
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Registered User
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Join Date: Oct 2005
Location: Junortoun Vic
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I use for visual an original TV Genesis.....amazing!
Certainly nothing wrong with the TV Petzval designs.
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07-07-2018, 01:01 PM
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Registered User
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Join Date: Feb 2006
Location: Sydney
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Quote:
Originally Posted by LewisM
TSA line is ONLY 120 now - the 102 has been out of production a few years now, replaced - oddly - with the FC-100 (not a wise Tak choice to cancel the 102 IMHO, as it was THE best 4" scope I have ever owned or used). I expect the FC-100 sells better, being considerably cheaper than the 102 ever was.
The design of the TSA is pure triplet, whereas the TOA is well-spaced triplet. The new fluorite FOA shares the same design principle, and is one of the highest Strehl production scopes ever made (it's for all intents and purposes a poly-Strehl of 0.995)
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Thanks Lewis. I wondered why I could only find the TSA120 listed.
What's with the tiny focuser and no dual speed at US$4430?
First thing would be to throw out the focuser and put a Feathertouch on it.
FOA is only the 60mm right? Sounds good but very small aperture.
If they could make a 110mm FOA it would be attractive.
Greg.
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07-07-2018, 01:04 PM
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Registered User
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Join Date: Feb 2006
Location: Sydney
Posts: 17,877
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Quote:
Originally Posted by LewisM
TSA line is ONLY 120 now - the 102 has been out of production a few years now, replaced - oddly - with the FC-100 (not a wise Tak choice to cancel the 102 IMHO, as it was THE best 4" scope I have ever owned or used). I expect the FC-100 sells better, being considerably cheaper than the 102 ever was.
The design of the TSA is pure triplet, whereas the TOA is well-spaced triplet. The new fluorite FOA shares the same design principle, and is one of the highest Strehl production scopes ever made (it's for all intents and purposes a poly-Strehl of 0.995)
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Quote:
Originally Posted by beren
Its a shame Tak don't have a "F" version of the TSA-120 with the larger focuser like the TOA-130. For visual its fine but hate the TSA-120 focuser for imaging, tried a few electronic focusers like robofocus and nothing worked when I had the large STT-8300.
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Yes it was the first thing I noticed about the scope, the tiny focuser. It would only handle small sensored cameras. Plus no dual speed ?? uuhhh what? Every scope I have seen recently listed has a dual speed focuser - every single one.
But then a lot of scopes need their focusers replaced. Too bad Tak doesn't sell OTAs with no focuser!! haha.
FC100 I take it is a fluorite doublet. It replaces the FS102?
Greg.
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07-07-2018, 01:11 PM
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Ultimate Noob
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Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
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Quote:
Originally Posted by gregbradley
FC100 I take it is a fluorite doublet. It replaces the FS102?
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The main difference between the FS102 and the FC100 range is that the FS102 had the fluorite element at the front where as the FC100 has the fluorite element at the rear. The FS series may have also been a bit beefier.
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07-07-2018, 01:45 PM
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Novichok test rabbit
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Join Date: Aug 2012
Location: Somewhere in the cosmos...
Posts: 10,388
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Quote:
Originally Posted by beren
Its a shame Tak don't have a "F" version of the TSA-120 with the larger focuser like the TOA-130. For visual its fine but hate the TSA-120 focuser for imaging, tried a few electronic focusers like robofocus and nothing worked when I had the large STT-8300.
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Stuart,
You can buy the 4" focuser directly from Tak and fit it to the TSA-120 directly - both share the 125mm tube.
Cost is...well... so FT may be a better option lol.
I personally find the Tak focuser just fine. Fitting the dual speed add on is so simple too, and not expensive (the FSQ-106ED's of course come dual speed as standard, unlike the old N model)
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