Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Any other Tal Klevzov users on this forum?

  • Please log in to reply
12 replies to this topic

#1 Edwin

Edwin

    Messenger

  • -----
  • topic starter
  • Posts: 426
  • Joined: 16 May 2007
  • Loc: The Netherlands

Posted 08 July 2018 - 08:23 AM

From around 1995 till 2015 Tal (based in Novosibirsk) produced some fine cats with a Klevzov-Cassegrains design, the Tal 150/200/250K. I rarely see something about these scopes in this part of the forum. As a user of a Tal 200K, my question is if there any other users of a Tal Klevzov, and if so, can you give some details ?

 

To start up this topic, some info about my 200K: I have no. 2001-95 with a F10 focal ratio and straight vanes. I bought it second hand some 10 years ago as a complete package in the big birchwooden case with the Tal GEM 2 mount. I don't use this mount, because it causes too much vibrations, the OTA now rides on a Orion Sirius EQ-G. For that I had to attach a Vixen-style dovetail underneath the standard Tal dovetail. I also replaced the focusser for a 2" Crawmach double speed, which is a really step up and a joy to use. The last modification I did on this scope is the fitting of a RDF, which I prefer above the (really good!) 10x50 standard viewfinder. 

 

I really like this scope, it gives very sharp views across the whole FOV, it cools down rather quickly and I don't need anything against dew due to its open design. The only disadvantage is its weight (24 lbs).

Attached Thumbnails

  • Tal 200K on Sirius EQG.jpg

Edited by Edwin, 08 July 2018 - 08:26 AM.

  • Andy Howie, eros312, Tyson M and 1 other like this

#2 tweeb

tweeb

    Lift Off

  • -----
  • Posts: 6
  • Joined: 18 Jan 2016

Posted 10 July 2018 - 01:57 PM

Hi Edwin,

 

I'm a new owner of a TAL 200K. Just bought it last week, from someone local secondhand but in pristine condition, only used 3 times. Came with an EQ5 but already got one of those, and I have an EQ6 in the obsy! It's Serial No 0795-2008 one of the newer ones - F8.5 with a 1.25in Crayford focuser. Bought it as I have an Orion Optics Europa 150 Newtonian, and had been given an old Vixen 102M, and had been thinking of getting a CAT - when this came up - after a bit or research - I had to have it! So it's installed in the obsy waiting for a clear sky!

 

All I have to do now if figure out how to fit my guide scope - although I suppose I could ditch the finder and use the finder rings. 

 

BTW You might want to correct your spelling of Klevtzov.

 

Cheers

 

Terry

 

TAL 200K Observatory
Album: TAL 200K
4 images
0 comments


  • Andy Howie and Edwin like this

#3 Edwin

Edwin

    Messenger

  • -----
  • topic starter
  • Posts: 426
  • Joined: 16 May 2007
  • Loc: The Netherlands

Posted 10 July 2018 - 02:04 PM

Wow, that's one of the newer ones, with curved spider I assume ?

 

 

 

came with an EQ5 but already got one of those, and I have an EQ6 in the obsy

Good idea to use the EQ6, I tried a LXD75 (which is equivalent with an EQ5), but found the OTA too heavy for it, too much vibrations.

 

 

 

All I have to do now if figure out how to fit my guide scope - although I suppose I could ditch the finder and use the finder rings.

Also good idea, I think the tube is too thick to drill good holes in it (although everything is possible of course) 

 

 

 

BTW You might want to correct your spelling of Klevtzov

Actually, it is Klevzov, Klevtzov or Klevtsov, all three are possible (but the npzoptics.ru site uses Klevtsov).

 

Good luck with your Tal, hope you enjoy it as much as I do !


Edited by Edwin, 10 July 2018 - 02:12 PM.


#4 Edwin

Edwin

    Messenger

  • -----
  • topic starter
  • Posts: 426
  • Joined: 16 May 2007
  • Loc: The Netherlands

Posted 12 July 2018 - 06:26 AM

Only one other user? Wow....



#5 Andy Howie

Andy Howie

    Ranger 4

  • *****
  • Posts: 304
  • Joined: 10 Sep 2005
  • Loc: Paisley, Scotland

Posted 12 July 2018 - 08:16 AM

Hi smile.gif

  I have a 200K also. 200mm F10 model. Bought in 2007, 2nd hand. Had lusted after one since 2000/01. Never been dissapointed with mine. A true joy to use.

 

# 0152 2001 with the 3 curved veins.

 

I use the Klevtsov spelling, as per the factory and perhaps more importantly, the optical designers name, Yuri Andreevich Klevtsov (Юрии Андреевиче Клевцове).

 

Edwin - You actually have quite a rare 200K. Can't be many with the straight veins! The scopes started with curved veins, changed to straight, for a very short run, then went back to the curved style, until the end of the F10 run and continued with the F8.5 version.

 

waytogo.gif ,

Andy



#6 Andreas-TAL

Andreas-TAL

    Explorer 1

  • -----
  • Posts: 74
  • Joined: 03 May 2014
  • Loc: North-Bavaria

Posted 24 August 2018 - 06:27 AM

Hi there!

Here is another Klevtsov user - located under Mid-European skies in Germany. I own the 10” version of the TAL-Klevtsov till 2011. I ordered the Klevtsov scope directly from Novosibirsk, what was quite difficult and thrilling (contract, customs, shipping ...).

Fortunately I got help from Sergey Maslikov - in 2011 he was the foreign sales director of FSUE. I’m still very pleased with my TAL-250K. A really “working horse” scope, providing very crisp and fine star images. Of course there are better scopes (I own a 7” STF from Russia too, a really “bombshell” on planets, definitely better than the TAL-250K). But my TAL-250K is a perfect Allrounder ...

Andreas

Attached Thumbnails

  • D13A2A68-EE91-42E2-B16B-E5621FCE277D.jpeg

Edited by Andreas-TAL, 24 August 2018 - 06:29 AM.

  • Andy Howie, Starman27, payner and 4 others like this

#7 Paul Sweeney

Paul Sweeney

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 19 Feb 2018
  • Loc: Heidelberg, Germany

Posted 29 August 2018 - 05:09 AM

Hi guys,

 

I have been thinking of getting one of these for a while now. I bought a VC200L because it was supposed to be superior to a C8, but mine is certainly not. I have read Wolfgang Rohr's reports, and searched the web, but I still am not convinced. So does anybody know or have a feel for the quality one can expect from these scopes? Are you guys just the lucky ones or are they generally good scopes?



#8 Andreas-TAL

Andreas-TAL

    Explorer 1

  • -----
  • Posts: 74
  • Joined: 03 May 2014
  • Loc: North-Bavaria

Posted 30 August 2018 - 03:53 PM

Well ... first of all the VMC or VCL design is not a Klevtsov design. Yes, both designs use subaperture correctors (and I think both are all spherical telescopes) but the details, especially within the so called “corrector unit” are different.

 

To be honest the VIXEN designs doesn’t convince me at all. The practical experiences of the VMC/VCL often reported thermal issues of the tube, sometimes quite “fat” bright stars due to the straight and quite thick spider veins and occasionally collimation issues.

 

But the Klevtsov design is quite sensitive too. To achieve an all spherical design the lenses within the corrector are quite extreme and their radiuses and tolerances are really very small. Unfortunately this leaded to a widespread manufacturing quality. Some TAL-Klevtsovs suffer from severe spherical aberration, downgrading their performance seriously below diffraction limited quality, some are barely diffraction limited.  “Photo quality” ... would someone in Moscow say, who is regularly testing telescopes, Klevtsov’s too ...

 

On the other side - have a look at Dimitry Makolkin and his moon images:

http://makolkin.ru/G...ry/gallery.html

or here at CN, too.

 

Looking at his images is the cheapest way getting a ticket into a lunar orbit 😜 ...

 

He uses a serial model TAL-250K for his extraordinary pictures. Of course he is brilliant in image processing, but with a lemon tube you can’t achieve these results. Anywhere he published the interferometry of his TAL-250K: As far as I remember about 0.9 Strehl - definitely a good one, but no phenomenal quality.

 

From my point of view the Klevtsov design (if the spherical aberration is under control) provides very crisp star images (what I would call “refractor-like”). Open clusters, star fields are a real pleasure. Very bright stars show a little halo, but due to the curved veins, quite well covered. The thermal equilibrium is as well much much better compared to the VIXEN subapertur tubes I have seen. Compared to a SC or VMC/VCL the Klevtsov images look a little bit fainter (there are many glass elements light has to pass till it reaches your eye). The central obstruction is about 35% (linear), so “blurred” images on planets (compared with a 7 or 8” unobstructed telescope) are unavoidable. But that’s in common with any other obstructed telescopes.

 

My conclusion is quite simple: If you own a good diffraction-limited Klevtsov type telescope (let’s say about RMS 1/18-1/20 lambda/wave) you will love it - definitely. It’s a precious keeper! BUT thats only the the half of truth. The other half is: You’ll have to find a diffraction limited Klevtsov. 

 

Andreas-TAL


Edited by Andreas-TAL, 30 August 2018 - 04:00 PM.


#9 Paul Sweeney

Paul Sweeney

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 19 Feb 2018
  • Loc: Heidelberg, Germany

Posted 02 September 2018 - 02:34 PM

Thanks, Andreas, for an honest answer. Since I got burned with the Vixen, I have only bought Newtonians and refractors. I really like the idea behind the Cats, but there always seems to be a quality issue with them. Some good, a few great, and some dogs. Is there any dealer who will deliver only good or better scopes?



#10 Andreas-TAL

Andreas-TAL

    Explorer 1

  • -----
  • Posts: 74
  • Joined: 03 May 2014
  • Loc: North-Bavaria

Posted 06 September 2018 - 03:42 AM

No, as far as I know they “big players” guarantee diffraction limited quality and nothing more. Sometimes the manufacturer itself offers “premium versions”: For example the “deluxe versions” from INTES.
The other way is to go to a small, highly skilled manufacturer, producing single, very individual telescopes. But choosing this way you need time and money.

#11 Mike 200K

Mike 200K

    Lift Off

  • -----
  • Posts: 7
  • Joined: 26 Nov 2018
  • Loc: 34.7465° N, 92.2896° W

Posted 26 November 2018 - 07:52 AM

Here is another owner!

 

F10 200K with straight veins, original owner. Imported mine some time around 1995 directly from Novosibirsk; and is after many years of use - except for a few dings - still in peachy condition mechanically, and optically...

 

recently retired i found finally the time to convert the internals of the flawed stepper drive with my own design, thus eliminating much of the PE, which was introduced mostly by the crappy reduction gear box. I left the worm drive alone, mine seems - after adjustments - to be mechanically quite sound. Can get unguided 3min exposures with nice round stars... 

 

upgraded the focuser to a GSO2, which is now hooked up to a arduino- based autofocus system. works well.

 

fiddling around with a focal reducer, did any of you guys tackle that?

 

currently building my own equatorial mount, hoping to complete that thing early next year...

 

Cheers,

Michael


  • Andreas-TAL likes this

#12 25585

25585

    Vanguard

  • *****
  • Posts: 2150
  • Joined: 29 Aug 2017
  • Loc: In a valley

Posted 14 January 2019 - 11:07 AM

There is a 150 on ebay. 2002 with curved vein spider. I was impressed by its focuser.



#13 SeattleScott

SeattleScott

    Skylab

  • *****
  • Posts: 4364
  • Joined: 14 Oct 2011

Posted 14 January 2019 - 02:27 PM

There is a 150 on ebay. 2002 with curved vein spider. I was impressed by its focuser.


These things are really hard to search for with so many different spellings. All I see is a bunch of water bottles!


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics