Upgrade Vintage Telescopes with New Focusers
If you have a very early scope with an Astro-Physics cast aluminum focuser (painted black), Jaeger's 2" focuser with red knobs or a 2" Japanese style focuser, the upgrade is more complex.


 

2" Jaeger's Focuser with Red Knobs

This focuser was provided with our very earliest refractors in the early and mid-eighties. The red knobs were a very distinguishing feature.

  • Shorten tube an unknown amount from the focuser end. We do not have one of these focusers available to measure. You can determine the amount of the telescope tube to cut off by comparing the length of the Jaeger's and current focuser. You may wish to shorten the tube further, if you plan to use a binocular viewer or other accessory that requires alot of backfocus. It would be wise to check the backfocus of your current setup before cutting the tube so that you can allow for all desired accessories.
  • Square the end of the tube.
  • Machine new adapter plate for the new focuser that will install on the end of the tube. Alternatively, if you have a 6" OD (5.88" ID) or 7" OD (6.88" ID0 tube, you can order the backplate (adapter plate) and Astro-Physics focusers from D&G Optical or have a custom adapter machined by Precise Parts.
  • Install new adapter plate squarely onto telescope tube.
  • Thread new focuser in place.

2.7" Focuser with Aluminum Casting

  • Shorten tube approximately 1" inch from the focuser end. You may wish to shorten the tube further, if you plan to use a binocular viewer or other accessory that requires alot of backfocus. It would be wise to check the backfocus of your current setup before cutting the tube so that you can allow for all desired accessories.
  • Square the end of the tube.
  • Machine new adapter plate for the new focuser. Alternatively, if you have a 6" OD (5.88" ID) or 7" OD (6.88" ID0 tube, you can order the backplate (adapter plate) and Astro-Physics focusers from D&G Optical or have a custom adapter machined by Precise Parts.
  • Install new adapter plate squarely onto telescope tube.
  • Thread new focuser in place.


2" Japanese Focuser

  • Shorten tube approximately 1 inch from the focuser end. You may wish to shorten the tube further, if you plan to use a binocular viewer or other accessory that requires alot of backfocus. It would be wise to check the backfocus of your current setup before cutting the tube so that you can allow for all desired accessories.
  • Square the end of the tube.
  • You can probably use the original focuser adapter, however you may have to machine a new one. Alternatively, if you have a 6" OD (5.88" ID) or 7" OD (6.88" ID) tube, you can order the backplate (adapter plate) and Astro-Physics focusers from D&G Optical or have a custom adapter machined by Precise Parts.
  • Install adapter plate squarely onto telescope tube.
  • Thread new focuser in place.

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This page was last modified: January 4, 2012

Astro-Physics, Inc.
11250 Forest Hills Road, Rockford, IL  61115, U.S.A.
Phone: 815-282-1513   Fax: 815-282-9847