Hi everyone and thanks a lot for the responses. Thanks Bob
@bobharmony jaytee
@JayTee and Henk
@SkyHiker
This endeavour ended up being a big fail.
Sorry for this long ramble, but I just wanted to share this experience. Well, since it turned out poorly, I really didn’t want to share, but need to.
I have been having issues with the mount for some time (really always). The issues were not as critical early on because I had bigger fish to fry learning
AP.
DEC was always an issue, but
RA was much more problematic.
DEC never did recover well after a dither or a reversal, but it was usually only slightly amount out and even though it took many, many corrections, the
DEC error in PHD2 was always lower than the
RA error.
In other words, I could live with it even though is did have some impact on my stars (due mainly to the
RA error).
Recently,
DEC error and recovery were unacceptable. Guiding total rms error was running 1.5-2.0 arcmin/sec where it had been running 0.7-0.8 a year ago. Most of the increase was related to
DEC now. Still had the same non-periodic spikes in
RA.
My last night out imaging, I had reduced the dither px to the minimum (2 px at the imaging sensor) and I still had the big
DEC errors because the mount would not recover from the dithers. The data was useless since it was full of pattern noise.
I have always been pretty handy, so I had to do something and started by removing the worm gear assembly, it looked pretty simple.
I have always had a really hard time balancing the small scope (Sharpstar 61) in
DEC because the scope is light and there was so much friction in the
DEC axis. I had always read that there was way too much grease inside which contributed to the axis stiction, so I removed the
DEC cylinder.
It came apart quite easily. Two machined journals on the cylinder that mated up to the opposite counterparts in the barrel. No bearings. Tons of grease.
I cleaned it up with mineral spirits, dried, greased liberally, wiped it off, and greased very lightly. Big mistake.
I slipped the cylinder into the barrel and snugged up the nut on the bottom. I re-mounted the saddle.
The assembly spun better than before, except there was a bit more friction in one part of the revolution. I kept spinning the cylinder thinking that the grease needed to be distributed better. I probably spun the cylinder 20-30 times and it started to bind up. The more that I tried to free the cylinder, the worse the binding got until it was completely immovable. It was so bound up that I had to use extraordinary measures to free the cylinder from the barrel. The binding/freeing up of the two components caused extensive galling to the cylinder and barrel journals.
So, the mount is pretty much junk at this point. Huge bummer.
It took extensive sanding/polishing of the journals to get the assembly back together. Of course, hand sanding machined journals is never a good idea, but I had little to lose at this point.
Upon re-assembly, there was much more friction than before and kind of gritty feeling. Not smooth. Not surprised, but together so far.
I am hoping that I can at least get it usable enough for visual, but I would be very surprised if that worked out. The whole
DEC rotating assembly is not smooth at all.
I am now where I was originally planning to start.
DEC worm gear adjustment.
Just messing with the screws is really a touchy and tedious procedure. Kind of sloppy! It seems really kind of hit-and-miss whether I can get it any better than it was before, especially now with the damage to the
DEC assembly.
For anyone interested in the AVX
DEC worm gear adjustment, this is the link that I will be using.
https://www.cloudynights.com/topic/7019 ... stment-20/
I do plan to actually mount a scope to this poor beat up AVX and see if it will at least slew and perform visual operations.
I will update with finding/results. And, will be looking for a new mount.
Jim
Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), ZWO OAG, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, ASI 220mm mini , IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut,
N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin:
https://www.astrobin.com/users/Juno16/