GSO 10" RC -- truss or tube?

Octane (Humayun) · #1 25-03-2017, 11:00 AM

Hi team,

I'm in the process of building my observatory (Absco pool pump cover shed thing) which is about 1.5m x 1.5m x (1.4m tall on the high side, down to 1.2m tall on the low side (skillion roof)).

I'm contemplating buying a GSO 10" carbon fibre RC.

Looking for your opinions re: truss or tube for observatory housing. There's about $500 between them, which is not inconsiderable when it comes to having to spend another $1,500 or so on a decent focuser (I'd love an Atlas, but, I can't stretch the budget that far at this point in time, so, a Feathertouch system will do).

It'll be mounted on a Losmandy G-11 on a short concrete pier.

A penny for your thoughts, re: advantages/disadvantages of both?

Thanks!

H

Atmos (Colin) · #2 25-03-2017, 11:02 AM

Just from some things I'd read a while back I would suggest the truss over the tube, it sounded like it was better mechanically. The trusses seemed to be stiffer and hold collimation better.

Having never seen either of them in person, I'm just going by what I remember reading from others

Octane (Humayun) · #3 25-03-2017, 11:13 AM

Hey Colin,

Cheers for that. Wow, I didn't realise trusses were sturdier? That's good feedback

H

Quote:

Originally Posted by Atmos

Just from some things I'd read a while back I would suggest the truss over the tube, it sounded like it was better mechanically. The trusses seemed to be stiffer and hold collimation better.

Having never seen either of them in person, I'm just going by what I remember reading from others

billdan (Bill) · #4 25-03-2017, 11:52 AM

If you do go with a truss setup make sure you have a decent shroud that blocks off outside light.
Not so much for capturing your subs at night, but you do not want any light penetration when doing flats.

Octane (Humayun) · #5 25-03-2017, 12:03 PM

Excellent suggestion, Bill.

I was going to set up a flat panel on one of the walls in the observatory to make it easier, but, if I'm doing dusk/dawn flats, the shroud would be indispensable.

Ta.

H

glend (Glen) · #6 25-03-2017, 12:21 PM

Having owned an RC tube version i can tell you one big difference which will be important later on, with the tube version, cleaning the primary is complicated, with the truss it is easy. The truss is also fractionally lighter out of the box, 300gms. Regarding the focuser, the linear rail focuser is much stiffer than the old models, i would try it before you upgrade, it may not need replacement. I would suggest the optional focuser collimation ring, to enable precise alignment of the focuser with the secondary centre spot. If you do buy a replacement focuser make sure it can be collimated. Buy a TAK Collimation Scope, you will need it. Astrozap has good shrouds which are light tight, as well as front screw mounted light shields (which can be important if your scope sticks up above the observatory walls). Have a look at the Kendrick secondary heaters for the RCs, you will need one. Kendrick supplies thin copper tape that can be applied to the secondary vanes to avoid using wires, which can make one vane thicker than another.
Have fun.

Octane (Humayun) · #7 27-03-2017, 09:12 AM

Thank you for the sage advice, Glen. All points noted to take into consideration!

Thanks again, all.

H

gregbradley · #8 27-03-2017, 10:04 AM

Thermal tube currents make closed tubes for long focal length scopes very non optimum. I had a closed tube 12.5 inch RCOS and could not get super sharp images out of it.

Greg.

LewisM · #9 27-03-2017, 11:21 AM

Not here to help with your RC, but H, you know call me if the FSQ is up for sale

I feel a connection to that scope

Octane (Humayun) · #10 27-03-2017, 01:46 PM

hahaha, I'm keeping it.

I could lend it out, though?

H

lazjen (Chris) · #11 27-03-2017, 02:39 PM

If you got the tube version of the RC, you could probably put the FSQ on top of it as well.

(Ok, not sure of the weight limits, etc).

However, I've got the CF tube version and while I like it, if I could have got the truss version at the time I would have done so - for the reasons previously mentioned, but also because it would look cooler.

spiezzy · #12 27-03-2017, 05:10 PM

hi there H
I have a Carbon Fibre Truss F4 10" Newt and the great thing I find is that it holds collimation all night due to the non thermal expansion and contraction it is also mounted on a G11 and the weight difference is quite big between a solid tube version I would not hesitate in recommending the truss version as Bill mentioned you need a light shroud I go mine from Teleskope Express fitted like a glove
hope this helps
cheers Pete