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Guiding

Compare an image taken with guiding on versus an image taken without guiding (Fig. 1). Both were 1200s exposures with the telescope near the zenith.

Figure 1

Steps to get guiding working

At the moment, it is a bit involved.

  1. Acquire a target for the principle instrument.
  2. At the telescope, remove the SBIG-4 camera from the GAM.
    • Loosen the screw above the camera, not to the right.
    • Turn it less than 1/4 turn, to loosen. It doesn’t need much.
    • Pull out the camera.
    • Hang it on one of the wires around you.
  3. Insert the CCD-Acquire-Eyepiece
    • This is located in the supply cabinet in the warm room.
    • It has an illuminated reticle.
    • Tighten the set screw gently but firmly. (go figure that one out)
  4. Move the AutoGuider field of vision to a blank region of the sky using the GAM controllers (+X, -X, +Y, -Y). Don’t move the pointing of the telescope itself.
  5. Take a dark frame.
    • Re-insert the CCD camera head, swapping out the eyepiece, of course.
    • Press the Take Dark Frame button on the SBIG-4 controller.
    • Swap out the CCD camera head with the eyepiece once again.
  6. Aquire a guide star
    • The CCD-Acquire-Eyepiece should be in the GAM, where the CCD camera head usually is
    • Centre on a bright star (experience required) again using the GAM controllers (+X, -X, +Y, -Y). Don’t move the pointing of the telescope itself.
    • Use the illuminated reticle (turn the know to turn on) and dead-centre the star.
    • Exchange the eyepiece for the CCD head. We are done with the eyepiece.
  7. Focus the guide star
  8. Set the exposure to get around 50 counts
  9. Calibrate. Takes a minute or so.
  10. Commence tracking

That’s it! Much of this procedure is subject to change, if and when the SBIG-4 controller is connected straight to a computer, making the eyepiece swapping and focusing moot.