Quote:Solid tube: Hot water heater looking, heavy, bulky, ugly, unprofessional, heat wave trapping, inefficient, ancient cumbersome tube.
8 f7.62 eq.
12 f5 Dob
Barly my 10 yr old faithful Bichon pup.
Quote: Once you start looking at telescopes 15" and bigger, tubes get massive.
Quote:Solid tube: Hot water heater looking, heavy, bulky, ugly, unprofessional, heat wave trapping, inefficient, ancient cumbersome tube. Truss: Sleek, professional, efficient, cool air flowing, practical, compact, versatile, modern, aesthetically attractive design.
"I have been paddling in the shallows of a great ocean of knowledge." - Sir Isaac Newton * * 15" F4.55 Starsplitter Dob & a Denk II binoviewer * * http://peaceofsky.wordpress.com/ Pacheco State Park Fremont Peak
Quote:It's a size issue as much as anything. Once you start looking at telescopes 15" and bigger, tubes get massive. Big truss dobs break down for easier storage and transport. Discovery makes split-tube dobs in the 15"-17.5" sizes, and I think maybe a 12" too. A friend of mine has both 15" and 17.5" Discovery dobs, and in my opinion, they are way more of a hassle to deal with than my 20" Obsession. I just ramp it up into the bed of my pickup truck and go--no heavy or cumbersome lifting at all. But, that's just me--to each his own.
Happy owner of-- A Mag 1, 12.5 inch Porta Ball A Dual Axis Equatorial Platform A PST Double Stack
Jeff -----TEC 140, Stellarvue SVR90T, SV115T20 and AT65EDQ refractors,Webster D14, C11 EdgeHD Lunt LS60THa solar scope double stacked with LS60FHaTelevue Pan 41; Ethos 21, 17; Nagler 31T5, 9T6, 7T6, 5T6, 3.5T6; Delos 10, 12, ES25, 14, 9Astro-Physics 900GTO with Rob Miller Tri36M TripodDM-4 Mount-Extension-Tripod w/ Sky CommanderDM-6 Mount-Losmandy Adapter/Extension-Berlebach Planet w/ Argo Navis
Quote:I've been trying to find a comparison between a truss and solid tube dob. Other than weight considerations are there any advantages between the 2 designs?
Quote:Thank you for the responses! You've certainly clarified this for me. I was worried about stray light but it seems an easy fix with a shroud if needed. Fortunately for me I don't have much to worry much about this in my yard. I live fairly rurally and have no really close neighbors.Again thanks for all the responses!Paul
12" Dob, 4" Mak, 3" APO, PST, bunch of green eyepieces & an understanding wife.
20" homebuilt truss dob 6" watson refractor
Quote: however, when it comes to visual accuracy, a solid tube is far superior than a truss for several reasons.
Quote:The biggest advantage I've found with solid tube dobs (homemade at least) is the relative ease in making the tube rotatable to bring the eyepiece to a comfortable position. For that reason I went with solid tubes up to and including 16" F/5. 10" and larger scopes I make also have the tube break in half for easier transport. The tube not rotating is about the only thing I don't like with my 20" truss dob.Dave
-DannyMy warehouseMy Channel
Orion xx14g Dob CPC 1100 w/Skywatcher 80ED piggybacked Coronado PST TMB 92L refractor AT Voyager mount Nexstar 6/8 mount Denk Big Easy binoviewers Oodles of eyepieces and other optical gadgets Past scopes Meade 8" reflector and 8" SCT
Quote:What is the tube made of?
Quote:Agree with Rex. I've never seen any appreciable difference in the views through truss or solid tube scopes. The optical alignment/collimation principles are the same either way.
Quote:Dave-I'm curious how you made your large tube dob (16") rotatable. I'm also thinking to build one like this.JimC
Quote:Quote:Agree with Rex. I've never seen any appreciable difference in the views through truss or solid tube scopes. The optical alignment/collimation principles are the same either way. I think it has to do with the effect of body heat drifting across the optical path. Shrouds do not block breezes with the same effectiveness as a solid tube.I have noticed that since I converted my 12.5 inch F/4.06 to a truss, it doesn't handle the high magnifications viewing double stars the way it used to. It's not a collimation issue, the collimation doesn't shift. One of these days to test this, I am going to replace the cloth shroud with a sheet of 0.060" ABS wrapped around to make a tube, it would be captured by the truss poles.Jon
Quote: That would be an interesting experiment Jon. As for myself, I just don't see any real effect of body heat with my scope. I'm not much of a double star observer though, so it's hard to say.
Quote:There are advantages to a truss--many actually:1) lower center of gravity--more stable2) much shorter rocker box--less shimmy and vibration3) lower weight--OTA easier to pick up and move in a pinch.4) easier to transport in a car--smaller and lighter segments5) easier to remove primary mirror for cleaning6) easier to create baffles above the primary to enhance contrast7) larger altitude trunnions for less sensitivity to balance and superior altitude movement.8) Better looking--more like a professional telescope. Often made of finely-finished wood.9) easier to collimate accurately because you can get closer to the primary and secondary mirror surfaces or focuser to see a laser dot or shadow of the centermarker.
Quote: I think Daniel is a serious planetary/double star guy and observes with a group of LA "whackos" (as opposed to San Diego or Oklahoma whackos) who are really into it. They often have the good seeing and it's a constant shootout between some pretty awesome planetary scopes.Jon
Quote:Quote: I think Daniel is a serious planetary/double star guy and observes with a group of LA "whackos" (as opposed to San Diego or Oklahoma whackos) who are really into it. They often have the good seeing and it's a constant shootout between some pretty awesome planetary scopes.Jon What's "good seeing"?
Quote:Quote:What's "good seeing"? Half arcsecond or better? Don knows more about Daniel than I do. I agree that in the larger sizes, trusses are far more practical than Tube Dobs... No doubt about that... Jon
Quote:What's "good seeing"?
10" F/4.7 Modified Skywatcher Reflector, 38mm Orion Q70, 17mm Modified Ultima LX, 10mm TeleVue Delos, 7mm Pentax XL.
Quote: My comment was more of a jab at the generally mediocre seeing I have to deal with in eastern Oklahoma.
Quote: One of these days to test this, I am going to replace the cloth shroud with a sheet of 0.060" ABS wrapped around to make a tube, it would be captured by the truss poles.