There may be a tiny amount of skin oil from your hands on the parts and/or the straps. Clean them with an alcohol wipe and try again. -Christopher Erickson Observatory engineer Waikoloa, HI 96738 www.

Be careful using freezing methods with cells that hold optics. They could contract too far and crack the optics. AP machines the cells for large optics a tiny-bit bigger if they know that they are goi

I have made shims up to 10mm thick to square-up some compound telescopes. And make triple-sure that the scope is tightly collimated first since you are squaring to the OPTICAL axis, not the OTA struct

I have worked on a 20" RCOS scope where everything was seemingly rigid, however there was a "parallelogram" sag going on that would progressively push the pointing off as the OTA pointed to low altitu

One of the things that RCOS did that I suspect contributed to the sag/flexure in the 20" scope is that they offset the truss mounting points on the secondary assembly from the primary assembly. There

Panasonic Toughbooks have serial ports and other cool features, like hard drive heaters and daylight-viewable screens. ftp://ftp.panasonic.com/pub/panasonic/toughbook/specsheets/31_spec_sheet.pdf Not

Not all Toughbook models have a serial port so read the specs carefully before buying. eBay has a lot of Toughbooks for sale. The Toughbook CF-30 looks like a good model suited for astro purposes. Chr

Wish list item for new hand controller firmware It would be great if the hand controller had an orthogonality evaluation utility that could be used during the day on a distant terrestrial target. Fidd

Tough call. I have both and love both and couldn't give up either one. If the extra weight doesn't bother you, go with the 900. Christopher Erickson Consulting Engineer Summit Kinetics Waikoloa, Hi 96

If the right button on the hand controller got bumped by accident... Christopher Erickson Consulting Engineer Summit Kinetics Waikoloa, HI 96738 www.summitkinetics.com

Smart Compass is a nice tool! Thanks! Christopher Erickson Consulting Engineer Summit Kinetics Waikoloa, HI 96738 www.summitkinetics.com

I would think that an air pressure switch would be greatly effected by temperature and barometric pressure. You could get a accelerometer/gyroscope/magnetometer break-out module from Sparkfun and alwa

A microswitch or magnetic reed switch mounted stationary on the bottom of the RA axis with tabs or small magnets mounted on the rotating side of the RA axis would allow you to sense if the RA axis has

I'll be there too! Christopher Erickson Consulting Engineer Summit Kinetics Waikoloa, HI 96738 www.summitkinetics.com

If there is a DEC error when flipping the meridian, I would suspect mechanical flexure someplace in the optical axis. Christopher Erickson Consulting Engineer Summit Kinetics Waikoloa, HI 96738 www.su

Like I said afore, RCOS scopes have more optical axis shift from OTA flexure than you would expect. DEC error after meridian flip doesn't surprise me in the least. If it is indeed OTA flexure, it will

The offset between the RCOS inner-truss mounting points and the outer-truss mounting points is one flex point but I suspect that there is another nasty one in the RCOS primary mirror mounting system.

The mount parts will be packed very, very well. Christopher Erickson Consulting Engineer Summit Kinetics Waikoloa, Hi 96738

Sorry for the delay in answering your message. I have been really-busy. The VYSOS-20 RCOS telescope flexure is very predictable. Solution has been to have a good T-Point model and use variable trackin

Your truss tubes may not be glued but the ones on VYSOS-20 certainly are. The gray epoxy is clearly-exposed on the ends. All of the truss connectors have the small set screw that you mentioned as well