2010/08/20

The 24″ scope is back in operation

Thursday evening, Gil and I went out to re-install the RA drive assembly with its new, larger angle steel bracket. Precision slots had been machined in the physics lab with my milling machine.

Installation went well and the telescope now slews well in RA in both directions.

FYI, due to some asymmetry in how the worm interacts with the worm wheel (that we discussed before), we needed to slide the RA trimmer out to the end, therefore putting the telescope slightly off balance.

Whatever works, works.

We also looked at a few stars. Maurice, as you found, the 60 mm eyepiece needs to be pulled out a bit from the focusser tube (and locked) so that the best focus lies within the travel of the focusser. The shorter-focus eyepieces seem to be OK. If this continues to be a problem, maybe I could make an extension tube, as the eyepieces are not all parfocal. Star images were reasonable given that the mirror had likely not cooled down, and who knows what the seeing was in all that muck.

We reset the finder scopes.

The pointing accuracy of the system leaves something to be desired. When Glen returns, perhaps I could get his permission to install TPoint on the observing floor computer. I will then do a mapping run which should ‘nail’ the slewing — that is, put the object in the field of view every time.

I shall be away in Calgary next week, so the mapping will have to wait until I return.

Bob