Hello everyone! I wanted to have some information from users who use this 'Newton GSO Truss 254mm F / 4' optical tube, your opinions and conclusions for which I don't find many reviews on the net!
...thank you
...thank you
GSO 10" f/4 Carbon Truss Newtonian
Hello everyone! I wanted to have some information from users who use this 'Newton GSO Truss 254mm F / 4' optical tube, your opinions and conclusions for which I don't find many reviews on the net!
...thank you
I own one. It's a good telescope, better than the skywatcher newt I had. I rarely have to refocus even after 10-15 degree temp change. There is some sag at the front because the rods are rather thin but you can collimate and compensate for that.
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There is some sag at the front because the rods are rather thin but you can collimate and compensate for that.
*This is a timely request since I will likely be getting a Newtonian in the near future (assuming one can be found in this market). So thanks Orooro for asking. The truss tube of one brand or another is under consideration if I go with a 10 inch. Matt's point that I quoted was not something I had thought of and now gives me pause. Matt, in your experience can you say how much weight you have on the focuser? I now worry that if I put a motorized focuser upgrade, filter wheel, etc. that might overweight the OTA via the sag you mention. Does your rig have all that stuff on it? Could a solution be that a matched counterweight placed on the side of the OTA opposite the focuser negate the sag effect? My concern is that, yes, collimation might be able to correct for issues in one position on the mount, but what happens as the telescope slews during the night?
Thanks,
Alan
Respectful Engaging
Alan Brunelle:There is some sag at the front because the rods are rather thin but you can collimate and compensate for that.
*This is a timely request since I will likely be getting a Newtonian in the near future (assuming one can be found in this market). So thanks Orooro for asking. The truss tube of one brand or another is under consideration if I go with a 10 inch. Matt's point that I quoted was not something I had thought of and now gives me pause. Matt, in your experience can you say how much weight you have on the focuser? I now worry that if I put a motorized focuser upgrade, filter wheel, etc. that might overweight the OTA via the sag you mention. Does your rig have all that stuff on it? Could a solution be that a matched counterweight placed on the side of the OTA opposite the focuser negate the sag effect? My concern is that, yes, collimation might be able to correct for issues in one position on the mount, but what happens as the telescope slews during the night?
Thanks,
Alan
No, a counter weight could be used to counteract this problem. I have moonlight, mono cam and 7 36mm filter wheel on mine with a coma corrector. The reason this happens is that the struts between the truss and the front of the scope in the small tubesection are too small of a diameter and dont provide any lateral support. I have seen people add beefier struts. With a laser on my scope I can lift the front of the scope under its own weight on a bench and it will move 1-2 mm off the center of the mirror.
That said here is a one of my best pics with it. It really is a good telescope that could be engineered a tad better. I probably dig into things more than most people though.
https://www.astrobin.com/yuqsua/
https://www.astrobin.com/yuqsua/
Thanks for the replies!
It can always be reinforced with carbon sticks as in the photo (found on the net)!
It can always be reinforced with carbon sticks as in the photo (found on the net)!
That clarified it for me. I hear that even solid tube Newtonians can suffer from some flexure near the focuser, with benefit of beefing up the tube with a large stiff plate around the focuser. So maybe this is no surprise. I do like what I see in the photo with the focuser mount that spans the area of the front assembly from the truss plate to the spider plate. With the added sticks, that should then be rock solid.
Thanks to both of you! Matt, you are getting great images from your setup.
Thanks to both of you! Matt, you are getting great images from your setup.
Well written Respectful Supportive
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