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TS Carbon 8inch f/4 Newtonian w/ 2" Baader Steeltrack Focuser

frolao

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laser_jock99

laser_jock99

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A list of the TS improvements over the GSO steel tube version- plus my comment

-- lightweight but stiff carbon tube "Made in Germany "

Nice but not 100% necessary. A few focus checks during the night with the steel tube version would sort out any tube 'movements'. Never seen any movement myself on the 8". I think the tube stiffness is more of an issue on the bigger 10" & 12" scopes where the same tube wall thickness is used (to keep weight down) but results in a flimsier structure. This can be addressed but requires more DIY skill.

-- better field illumination by optimized focus position

Not sure what this means- probably they have moved the main mirror 10mm up the tube to improve DSLR back focus distance. An easy DIY mod.

 

-- TS modified primary mirror holder and secondary holder

They added some different collimation knobs. If you're lucky they swapped out the factory springs for stronger ones. Both easy DIY mods.

 

-- comfortable collimation of main mirror and secondary mirror without tools

See above note about knobs!

 

-- diffraction limited main mirror

GSO factory standard mirror!

 

-- Better 94% reflection on main mirror and secondary mirror for a brighter image

GSO factory standard mirror!

 

-- Baader Steeltrack 2" Crayford focuser with dual speed - only 50mm height!

Nice- but I find the GSO monorail focusers very good anyway.

-- optimized focus position for astrophotography or visual observing

Probably refers to moving the main mirror up the tube slightly again?

 

So-a nice tube & focuser but otherwise stuff could easily you change yourself. Generally I would say always buy the best you can afford but whether that means it is 'good value' is down to the individual. As they say- you pay your money and make your choice!

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Macavity

Macavity

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Depends who arrives first at the kill. <G> But I genuinely enjoy a reasonable (positive!) critique of these

rather interesting scopes and their advertising. :)

There is an emergent concensus? Perhaps "not off the peg", but NOT quite a violation of trade description?

A little effort and a modded *steel tube* version might come some way to achieving performance of an:

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p5266_ANGEBOT-ASA-200mm-8--Astrograph---F2-8---Gesichtsfeld-D-60mm---Hyperbolisch.html (A mere snip at £6564.11) :D

But clearly HOW MUCH is debatable! But  this also depends on you objective? What are you after? An "Astrograph" for Large chip "classical" imaging? A "light bucket" for real-time video astronomy (my own purpose!). A *compact* 8-inch for visual observation... with coma corrector, maybe? etc. etc. ;)

P.S. I think the performance of a LOT of budget scopes (Not just F4 Newts) is somewhat blighted "for want of a hap'orth of tar"! But then, you can also get quite a LOT (of potential) for the money... :)

P.P.S. Also a fan of MONORAIL focussers - Ironically part of my endorsement of budget F4 Newts. I now have one (+ motor drive) on my MAK150 too. But again, a bit of screw-twiddling, to achieve optimum results. :p

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laser_jock99

laser_jock99

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Depends who arrives first at the kill. <G> But I genuinely enjoy a reasonable (positive!) critique of these

rather interesting scopes and their advertising. :)

 

There is an emergent concensus? Perhaps "not off the peg", but NOT quite a violation of trade description?

A little effort and a modded *steel tube* version might come some way to achieving performance of an:

 

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p5266_ANGEBOT-ASA-200mm-8--Astrograph---F2-8---Gesichtsfeld-D-60mm---Hyperbolisch.html (A mere snip at £6564.11) :D

That's quite a special scope I believe- certainly not just a tweaked £300 GSO Newtonian! The 3" coma corrector alone is an expensive item. Would be a nice instrument to have but currently out of my league. I have the 2" ASA Keller corrector/reducer which works with all three of my F4 Newtonians (giving a nice range of native plus reduced focal lengths). Sadly the 2" only gives a corrected image circle of 20mm- not enough to cover an APS-C DSLE chip (let alone a full frame 35mm CCD). So a 3" ASA Keller reducer is the way forward for large chip imaging.

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laser_jock99

laser_jock99

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I would be more concerned about steel tube constructions if I was experiencing large temperature gradients/change over the course of an imaging/observing session. If the range was sufficiently large then focus position might well shift. The true benefit of carbon fibre tube is the stiffness compared to a steel tube of the same weight. It is known for the position of camera/focuser assemblies to deflect or move slightly on the larger, steel tube scopes. A heavy camera (plus other hardware like filter wheels) exerts large forces on the focuser assembly. Any small shift in camera position at F4 could lose your collimation.

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frolao

frolao

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Thanks for the replies,

It's really difficult do decide! My problem in this particular issue is simply this: I panic with diy, and at the same time i´m not rich :)

Simply put, i´ll try to buy the best possible and i feel these TS/GSO Carbon would be good investment. Ofcourse they are tunned GSO's. For exemple some have BK7 mirrors, like this: https://www.teleskop-express.de/shop/product_info.php/info/p5782_GSO-Carbon-Fibre-Newtonian-Telescope-8--F-4---Tube-made-in-Germany.html with a monorail focuser, others have pyrex mirror with improved mirror holder like the first link i posted. It´s very confusing for a beginner, besides the price difference in these improvments, is this really a big leap? Should i jump directly to their ONTC´s insted of their UNC´s?

If i go for an OAG, plus EOS camera, or even an Hyperion zoom, with the monorail (maybe the  best price/quality option), will the regular 8" GSO steel tube stay still? I don´t even have a clue, my guess is that the 6" will...

So many questions...

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laser_jock99

laser_jock99

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 others have pyrex mirror with improved mirror holder like the first link i posted  

That is a seriously different scope to the basic GSO F4- different optics etc. (and nearly 5x the price!). Nice if you have the money.....!

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