One of the critical parts of production a homemade Newtonian reflector telescope is lining up the enormous mirror at the lower location of the tube. Attract a moment circle with your compass that is an inch smaller than the thickness of the strictly business mirror. Provided the mirror is six inches, the radius of the mirror is three inches. Subtract an inch and establish the legs of the compass at two inches. That Testament trail a four-inch circle (two inches less than six inches).
1. Decrease a square outside of plywood to fit your telescope tube. The tube must be two inches larger than the mirror. A six-inch mirror needs an eight-inch-diameter tube; a 10-inch mirror needs a 12-inch tube. The tailgate square should be the alike span as the width of the tube. An eight-inch tube, accordingly, gets an eight-by-eight-inch tailgate blank.
2. Trail two crossed diagonals across the square tailgate blank from corner to contrary corner. The "X" at the centre marks the centre of the square.
3. Establish a delineation compass for the breadth of the radius of the inside of your tube--about four inches for an eight-inch tube and so forth. Fix the mark of the compass on the centre of the tailgate blank and frame a circle. Adoption a saber adage to trim the corners along the Hand-bill compass marks. Trial to glare that the tailgate fits inside the telescope tube. Sand the edges provided you obligation to.
4. There are many methods for mounting the mirror, nevertheless, whichever you employment, the mirror Testament hold to be adjustable. Astronomers phone this method collimation. Yet a intelligible homemade mirror mount allows you to collimate your telescope's mirror.
Instructions
Mounting the Mirror
This circle marks where the tailgate bolts Testament life.5. Cut the moment circle into six segments, marking six spots on the border of the circle. Choose every other spot so that two of the three chosen face the cutoff corners of the tailgate. Drill 5/16-inch holes in the marks. Screw the 3/8-inch tailgate bolts all the fashion into the wood till the ends stick gone a half-inch.
6. Intersect a thin plenty of cardboard into a triangle that covers the ends of all three bolts. Exercise glue at the centre peerless underneath the cardboard triangle. Position the triangle so that the corners of the triangle cover the ends of the bolts. Next, glue three one-inch squares of masonite on top of the cardboard directly over the bolts. Tack down the center of the cardboard triangle onto the glue underneath till it dries. The triangle protects the bottom of the mirror from the bolt ends. The bolts can then be used to adjust the angle of the mirror once you've mounted the mirror.
7. Cut four rectangular wooden blocks one-inch square at the ends and three inches long. Attach a disk-shaped rubber furniture stop to one end. These are available in the furniture hardware section of the hardware store. They look like a firm round rubber disk with a central hole for a screw. Screw the rubber stop into one of the long sides near one end. Measure the thickness of the mirror and leave enough room between the lower edge of the stopper and the lower edge of the wooden block. This is where the edge of the mirror will sit.
8. Attach the four blocks with small screws or epoxy glue. Space them evenly around the inside of the telescope tube at the bottom. The stopper should be on the high side of the block and facing inward to the inside of the tube at the base. Leave enough space below the blocks for the tailpiece to push the mirror firm up against the rubber stoppers and far enough inside the tube for the tailpiece to be screwed in place.
9. Slip the mirror inside the three wooden blocks and push the edges up firmly against the rubber stoppers. Slide the tailpiece into the lower end of the tube so that the cardboard triangle presses firmly up against the base of the mirror. The mirror should compress the rubber stoppers on the mounting blocks slightly. Screw the tailpiece into place with small screws through the tube into the edges of the tailpiece.
10. Adjust the aim of the mirror by gently loosening and tightening the three adjustment bolts to change the angle of the mirror in its seat. Make only quarter turns at a time. Be sure not to over-tighten the bolts and break the mirror. Over-tightening the adjustment bolts can warp the shape of the mirror. You want the bolt heads to press firmly but not be stiff.
