Posts Made By: Bill Guinn

On the web site
http://www.astrosurf.com/demeautis/ep/pe.htm
is posted the perodic werror of various mounts. They shouw an "Arcane A40" does anyone know about this mount? Who makes it, where to get info?

I have a "new" byers 9" drive with a 1/2RPM Hurst MOdel A synchronous motor (P/N 3002-025). Though its truly new, for some reason the motor does not rotate, though it does vibrate so something internally is rotating. After taking apart the gear train it looks fine, free turning etc. So I think something is wrong with the "motor" portion only. The "motor" portion is not readily taken apart - or so it looks that way.

Given the very high cost of replacing this rare motor ($135) and 6 week order time, I wonder if there is not a couple of much cheaper options. First, I assume that someone might be able to fix it. Anyone know who could?

Second, I assume the "motor" portion of a 1/2 RPM motor is the same as a 2 RPM and 4 RPM etc. in the same Hurst series and that the only difference between these motors is the gear reduction. Given that 2 and 4 RPM motors are readily available and significantly cheaper (by > $100) could I buy one and just swap gear trains?

Third, is there a suitable replacement?

thanks in advance

Has any one bought and tested the lens manufactured (or shipped out of) Hong Kong frequently advertised on ebay? Below is the description on ebay:


Modern designed 8.5" F/12 professional telescope lens,doublet,air-spaced,included high quality aluminum cell. FULLY-MULTI-COATED for all four surfaces,over 97% light transmission. NEW,never used. star testing showed 1/6 PV,excellent airy-disc. quality is as excelent as D&G's which is the one of best achromat on the current market.

D=8.5" (222mm)

F=12 ( 2700mm)

Lens Type: BK7 + F3 (SCHOTT)

Glass grade: A

Coating range: visible light from 400nm to 700nm.

buyer pay $80 DHL shipping cost,three working days delivery to your door.

There are several large 8-12" achromats available on ebay from China. Very good pricing, but does anyone have experience with them? Anyone tested them?

Thanks for the feedback