Home made 4.5 inch Dobsonian
Home made 4.5 inch Dobsonian
This is my most recent project, made out of plywood and pvc pipe, as I hate cutting circular edge, I chose this design with minimum curve. This mount is made to a comfortable height for viewing. What is left to be done is painting. This project took me 6 weekends.
You do not have the required permissions to view the files attached to this post.
You really good at wood work!
"The universe is composed mainly of hydrogen and ignorance." HI to All,
Thanks for your comment. I had the first light last Friday with other members at USM. Although the light gathering power is much less than my 10 inch nevertheless Jupiter belts shown out quite clear with a three time barlow. Tested with star it turns round and symmetrical.
There is some backlash with balancing probably not enough of friction at the bearing, need to add a spring to solve the problem.
I am planning to sell this telescope at under Rm 1000.00. Anyone interested out there ?
Thanks for your comment. I had the first light last Friday with other members at USM. Although the light gathering power is much less than my 10 inch nevertheless Jupiter belts shown out quite clear with a three time barlow. Tested with star it turns round and symmetrical.
There is some backlash with balancing probably not enough of friction at the bearing, need to add a spring to solve the problem.
I am planning to sell this telescope at under Rm 1000.00. Anyone interested out there ?
Hi botok,
The primary mirror of this 4.5 inch is f6
Secondary mirror minor axis is 1 inch.
Spider is a single curve vane made from steel ruler.
Pvc Pipe is 6 inches diameter cut to suitable length to suit the focal length of the mirror. Allow extra length on top end to cut off stray light.
Mirror cell made of half inch thick plywood holding the mirror with three botchs of silicone.
The tail gate is of a triangular half inch thick plywood cut to suit the diameter of th pvc pipe. Hold to the tube with three wood screws
Three mirror cell holding screws with 3 eigth of an inch diameter spring. Three jammed screws of 9mm dia. screw with tee nuts embeded to tail gate.
The Mould is of plywood half inch thick cut into whatever shape you want.
Ground board is made up of two hexagon shape half inch thick plywood with bottom of the top piece lined with formica.
Three plastic furniture leg slide, white in color, as teflon pad.
Three rubber furniture leg plug for legs under the ground board.
The bearing is made of 2 pieces of 4 inches diameter plywood glued together with white latex glue to made it thicker for each side. The edge of the bearing piece is mounted with pvc pipe 1 inches wide glued with white glue as well. Two pieces of 1 inch long by half inch wide teflon mounted on the mount for the bearing to sit on.
The rocker cradle is made of two hexagonal piece plywood with cut out hole in the centre to hold the pvc tube, and 4 pieces of 8 inchesby 3and a quarter inch plywood to hold the hexagonal pieces together. A spring and turn buckle is added to the bearing to allow for friction adjustment.
That is all for the specification.
Hope that the specification is clear to you, I am not so good at describing it in words. If you have any further question do write to me.
Thanks
Mickath
The primary mirror of this 4.5 inch is f6
Secondary mirror minor axis is 1 inch.
Spider is a single curve vane made from steel ruler.
Pvc Pipe is 6 inches diameter cut to suitable length to suit the focal length of the mirror. Allow extra length on top end to cut off stray light.
Mirror cell made of half inch thick plywood holding the mirror with three botchs of silicone.
The tail gate is of a triangular half inch thick plywood cut to suit the diameter of th pvc pipe. Hold to the tube with three wood screws
Three mirror cell holding screws with 3 eigth of an inch diameter spring. Three jammed screws of 9mm dia. screw with tee nuts embeded to tail gate.
The Mould is of plywood half inch thick cut into whatever shape you want.
Ground board is made up of two hexagon shape half inch thick plywood with bottom of the top piece lined with formica.
Three plastic furniture leg slide, white in color, as teflon pad.
Three rubber furniture leg plug for legs under the ground board.
The bearing is made of 2 pieces of 4 inches diameter plywood glued together with white latex glue to made it thicker for each side. The edge of the bearing piece is mounted with pvc pipe 1 inches wide glued with white glue as well. Two pieces of 1 inch long by half inch wide teflon mounted on the mount for the bearing to sit on.
The rocker cradle is made of two hexagonal piece plywood with cut out hole in the centre to hold the pvc tube, and 4 pieces of 8 inchesby 3and a quarter inch plywood to hold the hexagonal pieces together. A spring and turn buckle is added to the bearing to allow for friction adjustment.
That is all for the specification.
Hope that the specification is clear to you, I am not so good at describing it in words. If you have any further question do write to me.
Thanks
Mickath