45 replies to this topic

[Defenderslideguitar]

My favorite  color scheme     the Vixen White tube with the what I always called  the Vixen green gray color scheme  like on my Vixen 80fl       is it Vixen mint green?

Edited by Defenderslideguitar, 03 February 2021 - 07:58 PM.

[Lucullus]

   Nice! Thanks so much for information, Terra!  It sounds like a serious performer. The reason Japanese optics were top notch was the level of competition between the manufacturers. Most of the best stuff is in the hands of Japanese collectors and never were exported. We are lucky to have a rare conduit in unique goods such as Koji Matsumto. I was reminded recently there was Japanese importer long before Koji that used to advertise back in the old Starry Messenger. Will see if I can find his name in an old mag.

      Can't wait to try mine under good skies. It's like having a TV 101 and a TV 102 in the same telescope. Great super wide fields but great on planets. A little false color has never bothered me. Sharp views and pushing high magnification without breakdown is only possible with great optics. 

1. How can it still have noticeable false colour with 5 lenses in it?!

2. It it's a TV 101 and 102 combined performance-wise, how does the TV 101 and 102 perform individually? I thought they are top-notch themselves?
 

[Terra Nova]

My favorite  color scheme     the Vixen White tube with the what I always called  the Vixen green gray color scheme  like on my Vixen 80fl       is it Vixen mint green?

I don’t know about the actual green tint color Barry. Seems to me, I heard someone call it mint green and that’s the name I have used. It’s really more of a light, metallic sage. I had a Nissan car close to that color once. They called it ‘sea mist’ green. I bought the car new and that was the actual paint color name.

[bulletdodger]

   The lens were added for field correction and not color correction. Basically a Petzval design with an additional flattener I think. 

     Well they are top notch individually but the TV101 is better for wide fields and the 102 is a better planetary. The 120 sits in the middle FL wise but more aperature than either. It is also bested by both TV's for color correction. 

[Terra Nova]

   The lens were added for field correction and not color correction. Basically a Petzval design with an additional flattener I think. 

     Well they are top notch individually but the TV101 is better for wide fields and the 102 is a better planetary. The 120 sits in the middle FL wise but more aperature than either. It is also bested by both TV's for color correction. 

I quite agree. It’s not an apo but way better than a subF10 achro. You get 120mm of aperture with a scope verging on 5” F10 D&G achro in performance (a maybe bit better color correction than the D&G, but a bit less resolution), and yet verging on an ST120 (F5) in wide field capabilities. It’s kind of a best of both worlds in that way, and those two are a better comparison in my mind than a TV 101 and a TV 102. I’m quite happy with mine. It doesn’t replace my 4” TV Genesis SDF or my Vixen ED102SS but nicely complements them. It’s a big refractor in a smaller package.

(BTW, from what I understand, the objective up front is an F11 or F12 120mm, air-spaced Fraunhofer achromat.)

[RichA]

1. How can it still have noticeable false colour with 5 lenses in it?!

2. It it's a TV 101 and 102 combined performance-wise, how does the TV 101 and 102 perform individually? I thought they are top-notch themselves?
 

Sub-diameter correctors don't work as well as full-aperture ED elements when correcting colour.  They are used by companies like TeleVue because they are cheaper and achieve the effect of field-flattening and increasing photographic speed, if not reducing the length of the OTA.. 

Edited by RichA, 18 April 2021 - 12:03 AM.

[Terra Nova]

The rear element is not only a field flattener, but it is also an ~2:1 reducer, and so in effect is does significantly reduce false color in Petzval systems like TeleVue and Vixen, because it allows the design to employ a physically much longer f.l. objective and achieve a considerably shorter e.f.l., thus greatly improving the Conrady index; (eg. a F6.67 telescope  with an F11 objective).

Edited by Terra Nova, 18 April 2021 - 07:02 AM.

[Terra Nova]

Sub-diameter correctors don't work as well as full-aperture ED elements when correcting colour.  They are used by companies like TeleVue because they are cheaper and achieve the effect of field-flattening and increasing photographic speed, if not reducing the length of the OTA.. 

TeleVue has used SD glass in the objective and Fluorite in the rear element in all its 101mm refractors since the Genesis SDF.

Edited by Terra Nova, 18 April 2021 - 07:05 AM.

[Lucullus]

The rear element is not only a field flattener, but it is also an ~2:1 reducer, and so in effect is does significantly reduce false color in Petzval systems like TeleVue and Vixen, because it allows the design to employ a physically much longer f.l. objective and achieve a considerably shorter e.f.l., thus greatly improving the Conrady index; (eg. a F6.67 telescope  with an F11 objective).

Does this also work for sub-aperture lens correctors of reflective telescopes?

[Mizar1957]

Vixen 120s 5 elements    EQ5 Pro  goto

 

Hungary, Szalafő.

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[CHASLX200]

I liked my 120.

[Dave Novoselsky]

I'll do, don't worry.

I have only one problem: too many telescopes and no time enought to use them... 

For the "new" Vixen I have to wait a couple of weeks, then I'll test it and give you my personal impressions.

 

Paolo

I can cure that problem for you

[Dave Novoselsky]

   Nice! Thanks so much for information, Terra!  It sounds like a serious performer. The reason Japanese optics were top notch was the level of competition between the manufacturers. Most of the best stuff is in the hands of Japanese collectors and never were exported. We are lucky to have a rare conduit in unique goods such as Koji Matsumto. I was reminded recently there was Japanese importer long before Koji that used to advertise back in the old Starry Messenger. Will see if I can find his name in an old mag.

      Can't wait to try mine under good skies. It's like having a TV 101 and a TV 102 in the same telescope. Great super wide fields but great on planets. A little false color has never bothered me. Sharp views and pushing high magnification without breakdown is only possible with great optics. 

“Most of the best stuff is in the hands of Japanese collectors and never were exported.” Sadly, very true.  When was the last time you saw an FCT offered for sale other than the occasional “refurbished” FCT 76s that show up on eBay?  Same as to Nikon and Pentax refactors, they remain firmly within the hands of collectors and rarely surface on the secondary market.  The prices when they do appear are usually staggering.

[Kitfox]

“Most of the best stuff is in the hands of Japanese collectors and never were exported.” Sadly, very true.  When was the last time you saw an FCT offered for sale other than the occasional “refurbished” FCT 76s that show up on eBay?  Same as to Nikon and Pentax refactors, they remain firmly within the hands of collectors and rarely surface on the secondary market.  The prices when they do appear are usually staggering.

They are out there, patience is certainly required, though 

[Dave Novoselsky]

They are out there, patience is certainly required, though 

As one shark said to the other, patience my a** I’m gonna kill something today.

[Kitfox]

As one shark said to the other, patience my a** I’m gonna kill something today.

 

I might know where there is a Pentax SDP125 that could possibly go on the market...I have a scope from this person, so I can recommend him...it won't be a cheap "kill", but it will be quite satisfying.  And you won't have to travel to South Korea to get it, like I did!

Edited by Kitfox, 26 March 2024 - 09:31 PM.

[deSitter]

As one shark said to the other, patience my a** I’m gonna kill something today.

ROFL

 

-drl

[John Croker]

interesting post which i found rather randomly. 

 

actually i do own a Vixen NA120S & an ED102SS the latter i am taking with me to my 'hill house' until the new year. 

 

up there i have an iStar 8" f/6 on a G-11 fitted with Claytons Castors which helps in wheeling from my garage onto the driveway. 

 

The 102 is a bit easier to set up out the back where i have a much better view of the south circumpolar region.( im in Australia )

 

havent used the NA120s for a long time but i might get it out. A few years ago i bought an ES ED127CF which is impressive but needs a bigger mount than the GPDX / Samson tripod combo i have for 'smaller' scopes. 

 

i was using the NA120S as a grab and go as it's pretty light for its aperture.

[John Croker]

Much though i love the sea mist its a bit wobbly as aa focuser.

 

Ive often wondered if there is a better one out there that would fit ? Any hints ?

[tomekL]

Beatufil telescope. There is one here you can buy: https://www.olx.pl/d...7-ID15kF85.html

Price is arround 3100USD.

[Terra Nova]

Beatufil telescope. There is one here you can buy: https://www.olx.pl/d...7-ID15kF85.html

Price is arround 3100USD.

That’s way too expensive! 2X max of what anyone in their right mind should pay. And it’s the Orion rebrand which automatically knocks it down another 25% over the Vixen original.

Edited by Terra Nova, 10 April 2025 - 12:58 PM.