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Counterweights, Stainless Steel:
Astro-Physics Counterweight

German equatorial mounts employ counterweights installed on a "counterweight shaft" to bring a telescopes with its installed accessories to balance. It is vital to the safe operation, proper maintenance, and tracking accuracy that the proper amount of counterweight be selected, and then properly positioned on the counterweight shaft. Once installed, these weights must move smoothly on the in order to rapidly accommodate any changes of loads, and be locked rigidly and with no "wobbling" on the shaft.

Astro-Physics counterweights are precision machined from 303 stainless steel. A precisely machined bronze sleeve is press fit into the center hole of the counterweight to prevent marring of the stainless steel counterweight shaft of the Astro-Physics mounts and to facilitate smooth and easy repositioning of the weight on the shaft regardless of mount position. The weights slip onto the shaft easily, and are then locked into the desired position with a twist of the large hand knob and brass pin assembly; no tools are required as the hand knob features a large plastic handle. The brass pin is permanently installed in the sleeve; its function is to reduce any possibility of marring the counterweight shaft.

The counterweights are ordered by specifying which mount they are for, and the weight in lbs. This is because counterweights made for a large mount such as the Model 900/1200 series mount will not fit onto the smaller diameter shaft of the Model 400/600/800 Series Mounts. The available weights are:

  • 6 lb. COUNTERWEIGHT (6SLCWT) for 400/600/800 Mounts
  • 9 lb. COUNTERWEIGHT (9SLCWT) for 400/600/800 Mounts

  • 10 lb. COUNTERWEIGHT (10SCWT) for 900/1200 Mounts
  • 18 lb. COUNTERWEIGHT (18SCWT) for 900/1200 Mounts

Keep in mind that you can adjust the position of the counterweight to counterbalance varying loads however, the addition of a guide scope or other heavy loads may necessitate additional counterweight(s). We suggest that you provide a counterweight total of 70 to 80% of the anticipated payload. Some starting points are:

For Astro-Physics Model 400/600/800 Series Mounts:
Astro-Physics Telescope Counterweight
105mm Traveler EDF Tube Assembly one 9 lb. weight
130mm EDF Tube Assembly one 6 lb. and one 9 lb. weights, or three 6 lb.
130mm EDT Tube Assembly two 9 lb. weights
155mm EDF Tube Assembly (2.7") two 9 lb. and one 6 lb. weights
155mm EDF Tube Assembly (4") three 9 lb. weights

For Astro-Physics Model 900/1200 Series Mounts:
Astro-Physics Telescope Counterweight
155mm EDF Tube Assembly (2.7") one 18 lb., or two 10 lb. weights
155mm EDF Tube Assembly (4") one 18 lb. and one 10 lb. weight
180mm EDF Tube Assembly (4") two 18 lb. weights
180mm EDT Tube Assembly (2.7 or 4") two 18 lb. weights
206mm EDF Tube Assembly (4") three 18 lb. weights


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