Hutech Astronomical Products
Equipment for the Serious Amateur Astronomer


Borg Intro

Converting a 100 Ach/ED Objective to a Series 80 Tube

Owners of a Borg Series 115 scope with 100Ach or 100ED objective can easily "downsize" to a Series 80 tube for a highly compact configuration well-suited for air travel to remote locations. Borg parts kit #2005, shown at right, includes all components necessary to mount the 100mm objective on the Series 80 tube as indicated in the following procedure:


Step 1.  
Prepare the #2005 kit to receive the objective by removing the hood cap and retaining ring as shown.


Step 2.  
On the Series 115 scope, unscrew the objective hood as shown.


Step 3.  
Unscrew the objective cell from the Series 115 tube. If the tube coupling ring was unscrewed along with the objective cell, remove it from the objective and reattach it to the Series 115 tube section.

Cut pieces of the self-adhesive felt strip provided and attach them around the periphery of the lens cell as shown. Four 1-inch lengths are suggested.


Step 4.  
Push the end of the Series 80 tube past the end of the hood and attach the lens cell. Once this has been done, pull the lens cell assembly back past the end of the hood and reattach the retaining ring to the hood to complete the conversion process.


When assembly is complete, the hood (shown extended at left) should extend and retract smoothly and hold any position set. Adjust the felt strips around the lens cell if necessary to achieve the desired amount of friction.

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