Re: 1/10 scale 200"

Tony Cecce, Corning, NY (CECCE_AJ@corning.com)
Mon, 24 Apr 1995 09:39:18 -0500 (EST)

The Corning Museum of Glass acquired it direct from Cal Tech about ten years ago. It is my understanding that the scope was essentially in unusable condition at Cal Tech for a number of reasons. The museum gave Cal Tech a new 8 or 10 inch SC in exchange for the scope. It was brought to Corning with the intent of putting it in the museum to complement the 200" mirror blank. Corning has a fairly rich history in telescope optics so it made sense to get this piece of history. Somewhere along the line it was decided to fix the scope and put it into a dome for educational and research purposes and was donated to Corning Community College. The scope is set up in a classical cassegrain configuration, f10. The mount is not really set up for use as a visual instrument (unless you like banging your head on heavy steel components) so the main use of this scope will be for ccd imaging.

We have tried to use some of our local ATM abilities to get this scope up and running but the magnitude of the problems has forced us to get professional help. We have settled on DFM engineering to rebuild the mechanics and install their scope/dome control system. We are in the process of securing funding to complete this.

The mechanical issues we have are fairly interesting. The hydrostatic oil bearings on the front split ring are not functioning properly. Much of this problem is due to the fact that the mount was built for southern California, and we had to install a 14 degree wedge under the front to compensate for the latitude difference here in western New York. The hydraulic system needs to be redesigned to give constant pressure. We also need to investigate potential problems with the spherical bearing on the southern end of the RA axis from the increased load of raising the north end. We will also be checking and reworking if needed the drive gears.

It is obvious from the optical assembly that this mount was never intended to be used as a scope. The story I heard was that installing optics was an afterthought once the model verified the effectiveness of the hydrostatic bearings and Surrurier truss system. The main mirror cell is a flat bottom pan which is in desperate need of redesign. We installed a cork sheet to prevent metal to glass contact, but that is about all it does. The secondary holder is likewise insufficient. Star testing has shown severe optical distortions from the mirror mounts. The baffling also needs to be redesigned, as well as the focusing system.

I would love to hear from anyone who has seen/used this scope. What were the views like? How was the scope used at Cal Tech? Who used this scope? Apparently the optics were refigured during the early 60's and we have always wondered why this was done and by whom. Any info you can provide would be deeply appreciated.

Tony Cecce