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GordonCopestake
Carpal Tunnel


Reged: 03/02/06
Posts: 2715
Loc: Newcastle-under-Lyme, UK
TAL 200K Klevzov-Cassegrain vs C8? new
      #1594294 - 05/09/07 10:48 AM

What are peoples thoughts on the TAL200K Klevzov-Cassegrain vs the C8? The TAL is 8" f/10: http://www.firstlightoptics.com/proddetail.php?prod=Tal200Kota

Anyone used one of these before?


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Gaz O'C
Pooh-Bah


Reged: 01/02/05
Posts: 1343
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: GordonCopestake]
      #1594360 - 05/09/07 11:14 AM

I know a guy whose just ordered one, I'll keep you posted.

--------------------
14" f4.5 Dob
10" Meade SCT
180mm f15 Mak/Cass
127mm f12 Mak/Cass
150mm f5 refractor
ED100
EQ6 Skyscan
HEQ5
EQ2

http://stargazerslounge.co.uk/


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GordonCopestake
Carpal Tunnel


Reged: 03/02/06
Posts: 2715
Loc: Newcastle-under-Lyme, UK
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: Gaz O'C]
      #1594368 - 05/09/07 11:17 AM

Wheres that "blow a rasberry" smiley? :P

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ABC
sage


Reged: 10/22/06
Posts: 422
Loc: Heidelberg, Germany
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: GordonCopestake]
      #1594538 - 05/09/07 01:02 PM

http://www.cloudynights.com/item.php?item_id=448
(just read the statement at the end of this review)

http://www.cloudynights.com/item.php?item_id=713

http://www.cloudynights.com/item.php?item_id=449

--------------------
Kind regards, Christian
Meade 178 ED
Meade 152 ED
Intes Micro Alter M500
Bresser 70/700 Achromat
CGE
EQ-6


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Levente
sage


Reged: 01/20/04
Posts: 310
Loc: Budapest, Hungary
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: GordonCopestake]
      #1594659 - 05/09/07 02:12 PM

I compared the TAL 200K to a C8 XLT and the TAL 150K to C6 XLT and booth cases preferred the SCs. I especially found the stars tighter in the SCs.

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GordonCopestake
Carpal Tunnel


Reged: 03/02/06
Posts: 2715
Loc: Newcastle-under-Lyme, UK
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: ABC]
      #1594673 - 05/09/07 02:18 PM

Thanks Christian, i'd forgotten about those!

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Rick
Post Laureate


Reged: 04/12/05
Posts: 3285
Loc: Tokyo, Japan
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: GordonCopestake]
      #1595312 - 05/09/07 08:21 PM

Aren't these the same basic design as the Vixen CATS?

Rick


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studentofoptics
member


Reged: 06/25/06
Posts: 21
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: Rick]
      #1595611 - 05/09/07 10:57 PM

No. They are slightly different. The major difference is that TAL uses a mangin secondary mirror. Vixen VMC series is based on Shafer-Maksutov design as published on TM #38. I am sure Vixen tweaked the designs. In all these sub-aperture corrector designs, the light goes through the corrector element twice, so they need to be made very accurately. Also, the design is quite sensitive to spacing of elements, so they needed to be mechanically rigid as well. It is pity that these designs are not being explored fully by telescope manufacturers as they hold much potential for amateurs.

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Andy Howie
super member


Reged: 09/10/05
Posts: 195
Loc: Paisley, Scotland
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: studentofoptics]
      #1601361 - 05/12/07 11:17 PM

Hi. The price(OTA) in the UK, for the 200K is very, very tempting. Difference of 250 'tween it and a C8. Just make sure you have a solid enough mount i guess, oh, and never, ever, try to fiddle with the corrector/mirror bolts. Only collimate the main mirror. Quicker cooldown than a Mak or SCT do you think due to open tube??
Shame it wasn't fitted with the 2" SCT thread at the back , like most other scopes. I don't think there's much in-focus either.
Andy

--------------------
Tal 200K Klevtsov, Tal 2M, Tal 1, Tal M, Tal Alcor, Burgess 90mm Fluorite, PZO T50x70, Carton 60/1000.
Too many eyepieces and mounts.


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Nuke
Galactic Traveler


Reged: 10/11/04
Posts: 193
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: Andy Howie]
      #1607352 - 05/16/07 04:03 AM

The newer version of the 200K is f/8.5.

And if properly collimated the scope equals commercial SCs. But where these scopes really shine is photography.

I think there is a 14" or bigger Klevtsov in ESO. I just can't remember.

--------------------
Intes Micro M703 Deluxe
Takahashi EM200 Temma II
Fujinon 16x70 FMT-SX2
Radians 6mm and 10mm
Panoptics 24 and 35mm
Takahashi LE 7.5ED


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Edwin
member


Reged: 05/16/07
Posts: 59
Loc: The Netherlands
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: GordonCopestake]
      #1610202 - 05/17/07 02:35 PM

I've a TAL 200K for a year now and I'm very satisfied with it. I've never compared it side-by-side with a C8, but some people that own a C8 looked through the TAL and said the views are comparable. The scope has some advantages and disadvantages:

+ very rigid and solid construction > nearly no collimation needed
+ open tube > short cool down time
+ spherical mirrors > easier to make so less chance on a lemon

- very rigid > you need a big mount; the OTA weights 12 kg !
- focusser could be better and accepts only 1,25"
- large central obstruction (35%)

--------------------
WO Megrez 88 FD (88mm F5,6) | Intes MK-67 (150mm F12) | TAL 200K (200mm F10) | AT Voyager | TAL GEM2 | Orion Sirius EQ-G


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stanislas
sage


Reged: 06/23/05
Posts: 260
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: Edwin]
      #1611264 - 05/18/07 02:44 AM

HI,
I saw views in both.
But for adding something about the difference, the C8 has shifting, the 200K not.
The C8 receive very well moisture on the corrector, the 200K not. The C8 is light in comparison with a 8x50 finder added, 6kgs at the total, the 200K 12kgs.
The 200K has good flatness correction and star diameters are specified, the C8 has no declared specification and a coma corrector reducer is welcome to improve this fact.
They have both 35% obstruction but high magnifications are better hold on the 200K because acuracy of optical surfaces are higher grade. P/V6 is actual on the 200K and just diffraction limited on the C8 (so P/V4 about).
Globally the 200K is the winner, stars are pinpoints rather in the C8 which is I have to recognise already good but with not the same acuracy. Focusing in spite of the rustic 200K focuser is more easily achieved with.
As there is no shifting (remember the OTA location from the meridian from east to west side, collimation has to be re-touched slightly) this is also a good point. HEQ5 is aminimal mount for support.
In spite of all that observations, I bought the C8 for 600 as a used one after testing, very low shifting (only 3 saturn diameters), widely used and accessories easy to find, collimations to undertake oftenly for very high resolution views.
Remains the moisture problem. In fact getting such OTA this is like to live with some back aches, leg aches on the beginning when you retire from the common life as a beginning older.
But it is possible when combining with to get results, consistent results.
With the 200K you will be a weighty younger.
stanislas.


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michiel
sage


Reged: 09/16/04
Posts: 483
Loc: The hague Netherlands
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: stanislas]
      #1616650 - 05/21/07 07:59 AM

I had one and I liked it.
http://www.cloudynights.com/item.php?item_id=951
michiel

--------------------
questar 3.5
14" F4.7 dob (on dark holiday location in france)
TMB 203/9 Achro (godzilla) on G41 with FS2
eq6 skyscan and altazimuth vixen custom d mount
Aries Chromacorr O1
baader widefield binoviewer (27mm prisms)
25/40x100 45 degrees chinese border patrol binos
15x50 canon IS
10x70 vintage bino
15x70 skymaster
25x100 apogee binos
50mm F18 brass

scopos 80mm F6 (semi apo) refractor as finder for godzilla
152mm F5.9 TS (semi APO) big grab n go


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stanislas
sage


Reged: 06/23/05
Posts: 260
Re: TAL 200K Klevzov-Cassegrain vs C8? new [Re: michiel]
      #1617222 - 05/21/07 01:58 PM

Your review between a 200 mak and a binocular is still amazing. I cannot understand which target you aim with.
If I take personnally my 20x80 this is also pinpoints that I get, also with my 152 mm refractor just achromat also.
Then what are you aiming considering the subject of the forum here, a comparison and report experiences between a C8 and a tal 200K.
Personnally if I had the mount and the budget at the time of my bought i surely acquired the 200K in spite of the 3 curved vans spider supports.
I am sorry cannot follow you.
stanislas.


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michiel
sage


Reged: 09/16/04
Posts: 483
Loc: The hague Netherlands
Re: TAL 200K Klevzov-Cassegrain vs C8? [Re: stanislas]
      #1618513 - 05/22/07 04:57 AM

Hi stanislas, I was just drawing attention to another report of my experiences with the Tal, as it is in another part of the CN reviews, people might have missed it. Forget about the comparison with the Bino, that has nothing to do with this thread.

--------------------
questar 3.5
14" F4.7 dob (on dark holiday location in france)
TMB 203/9 Achro (godzilla) on G41 with FS2
eq6 skyscan and altazimuth vixen custom d mount
Aries Chromacorr O1
baader widefield binoviewer (27mm prisms)
25/40x100 45 degrees chinese border patrol binos
15x50 canon IS
10x70 vintage bino
15x70 skymaster
25x100 apogee binos
50mm F18 brass

scopos 80mm F6 (semi apo) refractor as finder for godzilla
152mm F5.9 TS (semi APO) big grab n go


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