Quote:
Originally Posted by Sunfish
Thanks Marc. What a field. There is so much depth there. A lot of dedicated time to get to that level of detail .
Looks like the Losmandy is on track.
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Thanks Ray.
I've received the new bearings yesterday and I have the new couplers being machined this week out of stainless steel which is stiffer than brass so probably picking them up Friday. I also managed to source all the various greases and lubes I need.
The gearbox changes has made a massive improvement in tracking. I wasn't too sure about it TBH at first but the early measurements I did in pemPRO really surprised me. There is also no backlash in RA or DEC now. Because everything is tighter I'm able to lock the motors and gearboxes in line in relation to the worm axis in a repeatable way. There is no more slack.
One of the very obvious thing I noticed was the drop in noise levels. Outdoors I can't hear the mount slewing because when all the gears and couplings are square and in the right position you don't get that cyclical sound due to excentricity or stress.
The other night when I was shooting the chicken Oiii for a few seconds I got confused because I couldn't graph the RA and thought it was off the charts on the PHD windows until I got the first bump and realised it was flat lining under the DEC
Now I'm working on getting rid of the remaining PE which is in the couplers alignments and bearings. Change of lube on the worm assembly did a noticeable improvement as well in smoothness and I was able to tighten the meshing as a result without binding.
What works at a given temperature doesn't necessarily replicate at lower ones so I'm now looking into spring loading what I can. The first thing is trying to put a small belleville washer between the outer worm bearing and the worm. That would allow some play axially with temperature changes and minimise stress on the R4 bearings. I found one of the high precision RA bearing was damaged over the years. They don't like lateral stress. When the bearing is damaged you get a spike during one revolution of the worm. It was 0.8 second of arc on the worm frequency spectrum. Everything adds up.
I'm also looking into preloading the worm meshing to compensate for changes in temperature. Will start with DEC then if it works translate to RA.
When I have everything working I can start imaging with the CN-212 again. I'd like to get the mount under 1.5 or 1 arcsec peak to peak. The AO can pick up the rest if needed but I'd like to get everything as close as possible mechanically first.