Posts Made By: Howard Lester

Must be challenging for Meade... 8) The full page ad of the LX-90 in the May S&T states it's on a "rugged duel-fork mount."

En garde!

All right gang, this is how it was done: The technique was to dab the aluminum surface with large (~ 12 inch diameter) cotton swabs. With no lateral scrubbing motion allowed, the very wet, suds-filled pure cotton swabs were dabbed onto the surface manually, resulting in minimum friction drag and no scrubbing action to scratch the aluminum oxide film. Some 1600 pats with pole-handled swab heads (like mops) were carefully administered. The operation took six hours. The mirror was oriented zenith pointing throughout, kept wet with high purity de-ionized water, and rinsed thoroughly. The clean surface was dried in segments using an air-knife discharging some 20 cubic feet per minute of filtered dry air to transport and evaporate water beads off the mirror.

The results were terrific, with a factor of six reduction in measured (visual light) scattering (~7.5% initial scattering to ~1.2%), and a ~3% increase in reflectance at 500 nm (~86.5% reflectance to 89.5%). There is dramatic improvement in the mirror's visual appearance, and accompanying gains are expected in telescope performance.

The former process of blasting the surface with CO2 "snow" could not remove the well-adhered dust that had accumulated over the past 27 months. This is the first time we tried this washing method with giant "Q-tips," and we found it works quite well.. and apparently garnered a lot of laughs from the staff working on it.

Howard Lester, MMT Observatory