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GSO 12" f/4 Carbon Truss Newtonian

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11 replies to this topic

#1 John_K

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Posted 19 June 2017 - 06:42 PM

Hi guys,

 

 

Just wondering what everyone's thoughts are about this scope?

 

https://www.bintel.c...russ-newtonian/

 

https://www.optcorp....-newtonian.html

 

I currently use a 12.5" f/5 scope and need something it that will be more portable for me and will be only used for Deep Sky astrophotography.

 

The only issue I have with the spec I see is that there is only 51mm of back focus. My current set up uses 105mm of back focus which means I may be looking at having to get a new low profile filter wheel and OAG. As well, I currently use the Baader MPCC coma corrector and feel that I will also need a new Televue coma corrector to cope with the f/4 optics.

 

Also looks like the focuser will be inadequate and will need to be upgraded.

 

Thoughts?

 

John K.


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#2 stubeeef

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Posted 19 June 2017 - 07:06 PM

Looks sexy!

The 51mm may be enough if the trusses are measured for it to be what its advertised to be

>> An Imagining Newtonian <<

Only one way to find out, and we will love hearing about it...waytogo.gif



#3 magiclight

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Posted 06 July 2017 - 07:15 PM

I have had the scope for a week. Purchased from Bintel and shipped down to Dunedin NZ.

Very well made especially for a GSO and good value for the $$.

I replaced the GSO focuser with my 2.5" Moonlite.

The back focus is about 180mm above the focusing plate.

The primary is a conical.

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#4 glend

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Posted 07 July 2017 - 12:37 AM

Looks sexy!

The 51mm may be enough if the trusses are measured for it to be what its advertised to be

>> An Imagining Newtonian <<

Only one way to find out, and we will love hearing about it...waytogo.gif

'Looking sexy', is that a reason to pay twice the price for a normal imaging newt of the same size.  For an f4 its not that light weight either.  But marketing is everything these days, stick some trusses on it and charge double. Don't forget to buy a shroud too.

 

If JohnK already has an f5 newt, he is going to give up focal length. If JohnK has a standard GSO made newt he can simply buy a carbon tube from Tekeskop-Express that is pre-bored for standard GSO focuser, mirror cells, etc and just swap over. 

 

Sexy verses functional, is it worth a premium.


Edited by glend, 07 July 2017 - 12:42 AM.


#5 Eddgie

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Posted 07 July 2017 - 07:58 AM

My advice for anyone looking at a big astrograph would be to look at the Boren Simon scopes.  These are f/4 (native) and include a Keller reducer and coma corrector so the system can work at f/2.8.

 

I don't image, but I have the 6" f/2.8 version and I love love love it!    Seeing the huge and highly detailed Lagoon Nebula with IC 4685 and Trifid Nebula all in the same true field is so amazing and stars are sharp right to the edge of my 2.4 degree true field!

 

Boren Simon on Minitower.jpg

 

The Keller corrector mounts in the focuser and can be removed to use in other scopes though most scopes will need the primary moved up to reach focus (and possible secondary oversizing). 

 

A lot of people don't know about the Boren Simons, but they are a great option.

 

 

 

 

 


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#6 Eddgie

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Posted 07 July 2017 - 07:59 AM

Also, Telescope Express can build up a Newt up for you to your own specs, so if you need a lot of back focus they can do that.



#7 magiclight

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Posted 07 July 2017 - 07:59 PM

 

Looks sexy!

The 51mm may be enough if the trusses are measured for it to be what its advertised to be

>> An Imagining Newtonian <<

Only one way to find out, and we will love hearing about it...waytogo.gif

'Looking sexy', is that a reason to pay twice the price for a normal imaging newt of the same size.  For an f4 its not that light weight either.  But marketing is everything these days, stick some trusses on it and charge double. Don't forget to buy a shroud too.

 

If JohnK already has an f5 newt, he is going to give up focal length. If JohnK has a standard GSO made newt he can simply buy a carbon tube from Tekeskop-Express that is pre-bored for standard GSO focuser, mirror cells, etc and just swap over. 

 

Sexy verses functional, is it worth a premium.

 

I didn't purchase the scope because it was 'sexy,' I purchased the scope because I wanted a scope to hold collimation across the sky at f4 with the weight of an imaging train attached which it something my 10" GSO can't do. And yes, I have a teleskop-express carbon tube for my GSO 10" f4 (see image) which I have been using over three years of imaging. The problem with is this that it still has the original GSO primary cell and rather flimsy spider from the original $400 telescope. 

 

The teleskop-express tube was pre-bored for my Moonlite 2.5 and is not strengthen around the focuser.  Also the focusing hole was matched to my required back focus.

 

I don't consider the Truss GSO expensive. Especially compared to these:

 

http://www.telescope...htn-300mm-f-3.8

http://www.skyvision...s-mt-structure/

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#8 AstroCatinfo

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Posted 02 August 2017 - 05:45 PM

I have had the scope for a week. Purchased from Bintel and shipped down to Dunedin NZ.

Very well made especially for a GSO and good value for the $$.

I replaced the GSO focuser with my 2.5" Moonlite.

The back focus is about 180mm above the focusing plate.

The primary is a conical.

Do you have any more feedback about this scope? Have you been able to image with it?

 

Thanks for your help!



#9 mikefulb

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Posted 02 August 2017 - 09:14 PM

I'm interested in any imaging with this scope - I haven't seen any...



#10 magiclight

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Posted 03 August 2017 - 09:19 PM

The scope is working very well so far. Holds collimation and focus well at this early stage of usage.

 

It's not light weight but seems to be nice and ridged.  Good for astrophotography.

 

I'm using a Moonlite 2.5" focuser. 


Edited by magiclight, 03 August 2017 - 09:32 PM.


#11 AstroCatinfo

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Posted 04 August 2017 - 03:43 PM

Thanks for the info. Do you know if this focuser can be ordered together with the OTA?



#12 magiclight

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Posted 04 August 2017 - 07:00 PM

The OTA comes with the GSO focuser. You would have to order the Moonlite focuser separately with the appropriate adapter.  The Altair adapter is made for the scope. I ordered mine from the US https://focuser.com/products.php

 

I know that Altair Astro sells the 10" with that option https://www.altairas...Astrograph.html

 

Cheers Dave




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