Hi Everyone,
I was fortunate to get a used Quattro for Galaxy season. A little faster than my Esprit 100 and more magnification. I have seen some nice images with this scope.
I have not collimated a reflector before.
I have often read about collimating a reflector and the challenges therein for an F4 tube. Some find the process easy, others despair. So I though I would share my experiences with my first attempt at collimating a Quattro 200 with Sharpstar 1x MPCC and a ZWO ASI 183MC pro camera attached.
I first started the process with a laser placed into the focussing draw tube. The focuser fortunately has very little slop however I was surprised how when slightly loosening the lock screw and rotating the laser the point of light on the secondary mirror rotated describing a circle with 2cm diameter. I didn’t realise the laser it self needed collimation! After locating the three collimating hex screws (under the label and latex seals) I was able to align the laser.
I made a sight cap and aligned the secondary mirror. Then installed the laser and adjusted the secondary to direct the beam to the centre of the primary mirror. Next step was to align the primary to centrally focus the laser beam on the bullseye of the laser collimator.
I thought that would be the end of things until I focussed on an artificial star placed 17m in front of the scope and observed a squashed oval shaped artificial star and not the nice round artificial star I had hoped for.
I defocused the star and could clearly see the asymmetry in the rings with the darker centre a bit to one side of a deformed circle. Adjusting the primary collimations knobs I could now get a round shape but could not get the darker middle area to move to the centre the circle. I figured that the secondary might be out of alignment so I made some very minor adjustments to the secondary and was able to achieve a much nicer looking result (attached).
I would have hated to do this time consuming exercise at night with a real star - wasting imaging time. With practice and getting to know the equipment I would assume the process could be shortened. I hope that the collimation holds when the scope gets placed into position ready for action.
I certainly felt like giving my refractor a hug after this exercise!
Feel free to comment and let me know if I need some friendly guidance!
