Did the design of the 900GTO or SPA change at some point, so the RPA is not essential?

Chris White

At the beginning of the year I purchased a 2009 900GTO.  It came with the standard pier adapter, which I mounted everything on a Losmandy HD tripod with the AP FSA bolted right to the top.  I had multiple people tell me that adjusting azimuth was a bit of a pain with the SPA so I kept my eyes open for the rotating pier adapter.  I bought one when it popped up on the classifieds, but to be honest I havent felt any need to install it.  Adjusting azimuth with the SPA is buttery smooth and precise.  Am I missing out by not using the RPA?  Did something change at some point with the SPA or the 900 that improved adjustment?

I do have incentive to not use the RPA as it adds almost an inch to the height of my setup.  I have my mount in a very small back yard observatory that I built and while the extra height wont be a problem in position 5 for the refractor it cuts it close for the Edge scope I have when I close the roof.

And as any of you who have an observatory will attest... they make us even more LAZY as astronomers so breaking apart the setup to run a test sounds like work especially when everything is just sitting there ready to go on a moments notice! 


Robert Berta

For remote imaging I use a Meade Giant Field tripod. Originally with my 900 GTO I just drilled and taped holes to attach the mount directly on the flat top of the Meade. Used it that way for years. I than added a 1100 GTO for home observatory use but got the AP flat adaptor for both the Pier and another one for the Meade tripod. In both cases they look nice work well but frankly both worked fine just bolting to the top of the Meade tripod. I think many buy the rotating adaptor thinking that it will give more range of adjustment...it doesn't. Later I machined a cap for use on the Meade tripod that allows additional adjustment of about 15 more degrees in addition to the stock range of adjustment of the mounts.....I have my one metal lathe and milling machine. While it was a fun experiment.....it wasn't necessary frankly.