Truss Rod or Solid Tube?

[-George-]

Hi,

I am just wondering what sort of telescope design (at least on the physical) is the better option?

Truss Rod provides convenience, at a higher cost for the same level of telescope to a solid tube.

On the other hand,

Truss rod helps eliminate thermal issues inside a scope which hinder seeing, but at the same time, it promotes external interference.

A solid tube on other hand perhaps does not get rid of thermals as easy, but with 3 fans attached to the back etc, the environment can be a lot more controlled than a truss style with no external interference.

Is a Solid tube the better option then over-all or what?

And using a cover on a truss rod, does it become identical to that of a solid tube or not?

I can buy either sort, solid tube is $500 less than truss rod for the same scope/optics, which leaves me 500 for accessories (maps, telrads, collimation tools etc). Just wondering what the over-all better option is. I like the price of solid and if it does some how promote for a better setup (fans etc) then no point spending the extra $500 on truss since I do have the room for a solid tube.

[AG Hybrid (Adrian)]

If you observe regularly in an environment with high levels of dew, and extraneous amounts of stray light which you cant control - like street lights, advertisement signs and neighbors. Consider the solid tube. It will naturally reduce these 2 factors affecting effective observations easily.

If you like to travel to dark sky sites as well as observe from home. Consider the truss design for ease of transportation and invest in a shroud to reduce the stray light problem.

If you feel you are being deliberately persecuted with unneeded lighting like flood lights, street lights, near by sports fields and annoying neighbors. Consider investing in an airsoft rifle.

[graham.hobart (Graham stevens)]

A question I am pondering to.
Does the carbon fibre truss design have advantages over a solid tube CF?
My thoughts so far...
The CF truss (RC 10A) has two alloy dovetails on it so any CF advantages are ? really advantageous when these are taken into consideration, plus any kit on the top I suppose. (Re expansion/ contraction)
The baffling of the open design allows for stray light ingress so unless you are at a dark site then maybe a cover needed (? shade cloth or black felt - which leads me to?)
Dust covers? Any condensation or dust would be more of an issue with the truss, collecting dust on mirrors and dew would be painful so need a plan.
But/ the temperature equalisation would be quicker, and if you are not burdened by stray light and have a clear area to observe in (no sand or flying dust etc) then truss would be good, also looks damn sexy.
The rigidity is supposed to be the same, though online I have heard of anecdotes of other truss designs moving at certain positions (dependant on the load ?)
On here the info I gathered is that CF is stable vz focus compared to the ali tube, so I assume truss CF would be the same.
There is 0.2kgs difference I think between the RC10 and the RC10A truss, so not really significant.
I have been thinking about this for weeks and still haven't made up my mind!
Graham

[SkyWatch (Dean)]

I have made and used both. I currently use a truss, mainly for ease of transport: + the Police no longer question me about the cannon!
My 12" scope packs down to a small esky in size, and I can set it up in a couple of minutes without any tools or loose bits. Normally the collimation is fine. I use a shroud most of the time to minimise dust and extraneous light. Tube currents don't seem to be an issue, but I often leave the shroud up a couple of inches above the mirror for a while to assist in cool-down (I use 2 fans as well).
My only issues with the truss are that because it is lighter it is more susceptible to wind, and balance can be a bit trickier.
However, if you aren't worried about size, then the $500 saving sounds good.
With regard to CF tubing, my understanding is that there are no problems with thermal effects. I use aluminium tubing (straight from the rack at the hardware store!), and have had no problems at all.
All the best,
- Dean