GSO 12" f/4 Carbon Truss Newtonian

[John K]

Hi guys,

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

https://www.bintel.com.au/product/bi...uss-newtonian/

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.

[spiezzy]

Hi there John
I have the 10"version of this its a great scope and has the quartz mirrors you will be able to use the Baader MPCC on this works quite well you will need a 50mm extension for the back focus depending on your camera /imager I use a ASI1600MC I also shaped the focuser for a MoonLite motorised focuser with the extra long draw tube and instead of a curved mounting plate I used the flat option .
my scope had issues with keeping collimation in certain areas of sky it was shifting but a cheap fix was worked out ref to images it was only $48.00 and now is as stable as a brick as for the rest of the build of the scope its perfect
but go have a look at one the 10" is a beast but quite lite compared to the steel tubed ones hope this helps
cheers Pete

[John K]

Great work on the mod there Peter, looks great!

So how much back focus do you have now? and what mount are you using?

From your scope, can you see the trusses being easy to shorten and re-attach as a further mod to increase back focus?

With an OTA weight of 23KG for the 12" I was hoping to mount it on a EQ8 but after all the issues with this mount I am now reconsidering and torn between getting minimalist mount such as a Losmandy G11GOTO or really biting the bullet and getting a mount for life such as an AP1100.

Decisions!!

[spiezzy]

hi there John
I have mine on a G11 mount and it handles it very well I have a Stellavue 80mm finder and a TS 80mm guide scope I re mounted these at the back of the scope as you need a bit of weight at the rear to achieve balance not sure if you will have the same issue with the 12" but there are tapped holes around the rear cell rings where you can re mount the losmandy plates I will get a pic of my set up for you to look at to achieve focus I still need an extension I noe have a 47mm Baader click lock extension works a treat
cheers Pete