I am building a bi-newt out of a pair of Meade 114NT's.
The concept it straightforward. Using the stock focuser, I have positioned the primary closer to allow a star diagonal to be used.
At the high mag position, the focuser is almost at the perimeter of the tube and it can come out for lower magification. Since the tubes are side by side, the IPD will be too close when the focuser comes out. I must bring the tubes closer to the IPD to make up the difference.
One tube is fixed, the other must be able to move parallel about 3".
Imagine the tubes as bazookas and at a 45 degree viewing angle. I need to be able to screw adjust the moveable one closer or further from the fixed one.
My first thought is to use 2 parallel 4x6 rectangles made out of 3/4" formica covered plywood. Four 1/2" diameter bolts with smooth shafts to slide one board to the other. At the center, a hex head bolt with a bearing on one board and a "T' nut on the other. Turn the bolt and the boards will come together or spread apart.
Focusing will be a 3 step process. Focus left eye, focus right eye, adjust IPD.
Before I cut; comments, advice, ideas please.
Thanks,
Stu
The concept it straightforward. Using the stock focuser, I have positioned the primary closer to allow a star diagonal to be used.
At the high mag position, the focuser is almost at the perimeter of the tube and it can come out for lower magification. Since the tubes are side by side, the IPD will be too close when the focuser comes out. I must bring the tubes closer to the IPD to make up the difference.
One tube is fixed, the other must be able to move parallel about 3".
Imagine the tubes as bazookas and at a 45 degree viewing angle. I need to be able to screw adjust the moveable one closer or further from the fixed one.
My first thought is to use 2 parallel 4x6 rectangles made out of 3/4" formica covered plywood. Four 1/2" diameter bolts with smooth shafts to slide one board to the other. At the center, a hex head bolt with a bearing on one board and a "T' nut on the other. Turn the bolt and the boards will come together or spread apart.
Focusing will be a 3 step process. Focus left eye, focus right eye, adjust IPD.
Before I cut; comments, advice, ideas please.
Thanks,
Stu
