STX-16803 backfocus question

Discussion in 'STX and STXL' started by Gerald Sifferman, Apr 17, 2019.

  1. Gerald Sifferman

    Gerald Sifferman Cyanogen Customer

    Joined:
    Apr 15, 2019
    Messages:
    5
    I recently purchased the STX-16803 Ultimate package which includes the camera and FW7 filter wheel, followed by the STX-guider and the AO-X. The Optical Backfocus chart for the STX-series cameras doesn't list the STX-guider backfocus component, but the product literature for the guider says that it takes up 1.1-inches (27.9mm). I would like to confirm that my backfocus is the sum of 67.1mm (camera/FW7/3mm filters) plus 27.9mm (STX-guider) plus 26.6mm (AO-X) plus 17.1mm (3-inch accessory ring). This totals 138.7mm of backfocus. Do I have this correct? Thank you in advance!
     
  2. Doug

    Doug Staff Member

    Joined:
    Sep 25, 2014
    Messages:
    6,170
    That is correct.

    I should mention that the accessory ring only adds the 17.1 mm if you screw into the threads on the end of it. If you use the dovetail instead it only adds 5.08 mm (refer to the diagram in the back of the STX manual).
     
  3. Gerald Sifferman

    Gerald Sifferman Cyanogen Customer

    Joined:
    Apr 15, 2019
    Messages:
    5
    Thank you!
     

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