I spent a couple of hours yesterday taking the imaging Sky 90s off the mini-WASP frame, collimating them with the Takahashi collimator, and then putting the whole thing back together again. Well – as far as the collimator goes, both Sky 90s are pretty much spot on with the collimation, now just need to see whether an imaging camera agrees with the collimator.
The two imaging Sky 90s are the 9-grub screw collimation adjustment version, and collimating these scopes is relatively straightforward (I wouldn’t say easy). I also have one of the original 3-grub screw versions of the Sky 90 and as far as I can see it is not possible to collimate these using the grub screws (the reason for this is obvious if you take the lens cell apart). So what I might do with this Sky 90 is get the lens cell modified so that I can adjust the lateral position of both the front (Fluoride) lens and the rear (glass) lens of the doublet and get myself a third viable imaging Sky 90. This is a LONG term project!