Atmos
29-12-2015, 11:27 PM
It is a bit of an exaggeration I suppose but it isn't working properly now so therefore it is broken!
Over the last month or two I have been having more and more trouble keeping round stars, have not been sure whether it is due to differential flexure of my guide scope, the warmer months bringing greater temperature differentials or if the internals have just needed a bit of a spring clean.
Last week I was watching my guide graph in PHD and I was noticing some random 4-5" peak jumps. Unsure whether they've always been there or if they are new, for me this put a tick in the "spring clean" box.
I am for forth owner of this mount, don't know anything about the first, the second greased it not too long before selling it to the third who belt modded it and used it a couple of times over 12-24 months. Figured it may need a little TLC.
I pulled the shafts and bearing out, they looked like they were still well greased and potentially with better grease than I had on hand so I left everything the way it was. I tried and failing to get a look at the worm gears, failed meaning that I had failed to realise that the belts were stopping me from getting into the RA and DEC gear areas ;)
So I have since put it all back together, realigned gear housings with the tiny hex bolts so that everything meshes together without any nasty grinding. Did 360° slews inside to double check that there was no funny noises, took about 45 minutes to get it all slewing with good meshing. Mostly just wanted to get rid of the tiny bit of wobble in the RA axis that I had introduced.
Set the scope out tonight, got it all ready to go, pointed it at Canopus to get focus (it got as close as it usually would considering that I roughly eyeball parked position). Then... Star trails in 2 second exposures, didn't take long before Canopus was out of frame. I could hear that the motor was tracking but the mount wasn't tracking with the sky!
So, my plan after work tomorrow is to do a full mount deconstruction, remove the gears and belts and everything. I am thinking that I may have, in my absolute lack of know how with what I was doing, stretched the belts. It slews and moves perfectly fine when everything is moving quick but if the belts are not as taught then it may just be taking AGES to pick up the slack as it were.
Does anyone have any other thoughts?
Considering that it only appears to effect the sidereal tracking rate, I figure it has to be something small. Won't really have an idea of what it looks like inside the RA and DEC worm drives until tomorrow but any suggestions are most welcome :)
Over the last month or two I have been having more and more trouble keeping round stars, have not been sure whether it is due to differential flexure of my guide scope, the warmer months bringing greater temperature differentials or if the internals have just needed a bit of a spring clean.
Last week I was watching my guide graph in PHD and I was noticing some random 4-5" peak jumps. Unsure whether they've always been there or if they are new, for me this put a tick in the "spring clean" box.
I am for forth owner of this mount, don't know anything about the first, the second greased it not too long before selling it to the third who belt modded it and used it a couple of times over 12-24 months. Figured it may need a little TLC.
I pulled the shafts and bearing out, they looked like they were still well greased and potentially with better grease than I had on hand so I left everything the way it was. I tried and failing to get a look at the worm gears, failed meaning that I had failed to realise that the belts were stopping me from getting into the RA and DEC gear areas ;)
So I have since put it all back together, realigned gear housings with the tiny hex bolts so that everything meshes together without any nasty grinding. Did 360° slews inside to double check that there was no funny noises, took about 45 minutes to get it all slewing with good meshing. Mostly just wanted to get rid of the tiny bit of wobble in the RA axis that I had introduced.
Set the scope out tonight, got it all ready to go, pointed it at Canopus to get focus (it got as close as it usually would considering that I roughly eyeball parked position). Then... Star trails in 2 second exposures, didn't take long before Canopus was out of frame. I could hear that the motor was tracking but the mount wasn't tracking with the sky!
So, my plan after work tomorrow is to do a full mount deconstruction, remove the gears and belts and everything. I am thinking that I may have, in my absolute lack of know how with what I was doing, stretched the belts. It slews and moves perfectly fine when everything is moving quick but if the belts are not as taught then it may just be taking AGES to pick up the slack as it were.
Does anyone have any other thoughts?
Considering that it only appears to effect the sidereal tracking rate, I figure it has to be something small. Won't really have an idea of what it looks like inside the RA and DEC worm drives until tomorrow but any suggestions are most welcome :)