| DIY Counterweight Bar |
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Introduction
A counterweight for a telescope is used to balance it's weight so that more accurate tracking and guiding may be achieved for astrophotography. A well balanced telescope takes a lot of strain off the worm drives and gears, making the mechanical components last longer.
Materials: (Mainly scraps)
1 piece of 20 x 20mm aluminium square tube @ 500mm long
2 pieces of aluminium threshold plate @ 40mm long 1 piece of 25 x 25mm steel square tube @ 25mm long 1 piece of 60 x 60mm steel square tube @ 200mm long 2 pieces of 60 x 60 x 2mm steel flat plate 1 Bottle of Lead shot 2 x M5 socket head set screws 2 x M5 hex bolts and with nuts and washers 1 x Bucket of initiative
Step 1. Measure the distance between the mounting screws at either end of your OTA and cut 20 x 20 Aluminium bar to suit.
Step 2. Drill holes in the ends of the 20 x 20 square tube and in the centers and sides of the two threshold plates, to match holes in the OTA. Step 3. Weld steel plates over the ends of the 60 x 60 steel tube to seal it. This is your weight. File and sand to smooth off. Step 4. Drill a hole in one end of the weight and pour in lead shot equal to the weight needed for balance. Step 5. Seal the hole with a cap, tape or a screw if you want to tap the hole. Step 6. Drill and tap a hole in two opposite sides of the 25 x 25 steel tube. Screw in M5 socket head set screws. Step 7. Weld 25 x 25 steel tube to the centre of the 60 x 60 weight. Sand and paint if you wish. Step 8. Slide the completed weight over the 20 x 20 square tube. Step 9. Using the M5 hex bolts with nuts and washers, assemble the threshold plates onto the ends of the 20 x 20 tube. Step 10. Using the existing screws in the OTA (You may have to get slightly longer ones now) Attatch the counterweight bar to the OTA Now all you have to do is release your clutches and adjust the position of the weight so that the telescope balances. *Afternote* Once you are sure you have your scope and attached imaging equipment set in stone, You may want to heat the counterweight bar over a gas burner until the lead shot melts. This will stop the weight shifting mid-slew.
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