Tuesday, November 19, 2019

Baby Telescope

I thought that I would share baby pictures.

This is the mirror cell.  What it replaced was made of plywood.


From the side.


You may have noticed the black rings.  These came off a 5" refractor which suffered cross threading of the M6 thumbscrews, so I retapped the holes to 1/4"-20.  I used weather stripping to get the ID of the rings to fit this 4.5" OD PVC tube.

The rings are attached to this base.
I drilled 1/4" holes in each end.  These holes should be counterbored to make the hex head bolts flush, but my mill is at Sherline for some TLC.  Attempting to counterbore with a 3/4" end mill in my drill press, even at 500 rpm, just shook the drill press vise and produced no useful counterbore.  When the mill returns, I will do this.  The 1/4"-20 bolts screw into the bottom of each ring.  In the center of this plate is a 1/4"-20 hole for attachment to a camera tripod. 

Looking down the mouth:
Yes that screw and wingnut should be painted flat black now that the diagonal holder is properly positioned front to rear.  

I am going to paint a phosphorescent paint stripe down the tube for aiming.  A finder on a scope that has a magnification range of 10-50x makes no sense.

The 31mm diagonal is a bit too large for this 3" mirror.  In daylight, this gives a black dot in the middle of the field of view for the 35mm eyepiece.  The only solution would be a 25mm diagonal, but such a diagonal holder size would preclude collimation adjustment.

I could just barely make ut Saturn's rings at 39x, and I can understand why Galileo was confused.



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