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matt_baker

CGE Wrong Pier Placement

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1 hour ago, teoria_del_big_bang said:

image.png.9fab370ccc05aa50264b53283156cefd.png

Steve

Remove one of these screws to see if the thread is in the outer part, if it is they may only screw into a groove to lock the top piece so loosening all three would allow rotation.

If the holes are plain and the thread is internal then it's a non starter.

Whatever it's not a one person job.

Dave

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Is this issue the only reason why such a potentially great facility has been unused?    🤔

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7 minutes ago, Peter Drew said:

Is this issue the only reason why such a potentially great facility has been unused?    🤔

Only 1.5 degrees out of PA doesn't make it unusable, should still be able to observe / image with it.

Dave

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I'm going to go over tomorrow since the weather is awful at the moment and pictures from all angles.

This is clearly getting confusing, both for everyone here trying to help and myself included.

To answer some of your questions:

I will have a look tomorrow if there's another hole further round for the azimuth bolt to sit in

It is easily rotatable in azimuth however, it can't rotate any further since it has reached its limit and needs rotating more.

I think there are designated holes for the three nuts to be in place with for the mount, and I'm not sure if there are others further around

The pier is bolted down with 4 levelling screws onto a steel/concrete pier

Yes, it is possible to observe and image with it but I always have to keep adjusting because it constantly drifts.

Edited by matt_baker
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Also, there are various reasons why the observatory never gets used, although now I have a key, I intend to use it whenever I can.

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One way I may have found how to do it, is that in the center of the pier plate at the bottom, is there's a screw which must thread through to the mount itself, so by loosening that, you're able to turn the mount and tighten it back up again?

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Brilliant suggestion! :thumbsup:

I think I can see that central screw through the hole in the base. The much longer one! Good luck reaching that with a spanner!
Is there a nut inside the PA support fork? We don't have a picture of that area of the mounting.

I think the large, lower, galvanized screws are just levelling jacks.

Do  a search for CGE azimuth adjuster for further clues.

Edited by Rusted

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2 hours ago, matt_baker said:

One way I may have found how to do it, is that in the center of the pier plate at the bottom, is there's a screw which must thread through to the mount itself, so by loosening that, you're able to turn the mount and tighten it back up again?

I think this will be the solution to the problem. The plated screws do appear to be levelling jacks now that we have a better view of them.   😀

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I searched for ages about the CGE and found reference to a "socket head screw" in, or projecting from, the mounting top plate. Nothing visible on "yours?"
Later examples seem to have a worm, or threaded rod, fine adjustment in azimuth. A costly design solution unless you need it every night.

Owners complained [in another place] about the PA altitude adjustment being heavy but found the azimuth easy.
Presumably they could just rotate the tripod if they hit the end stops.

It really makes you wonder if the mounting was set up wrongly in the first place.
With no further azimuth adjustment possible because of the solid pier.
Even so I find it hard to believe they'd make a mounting which couldn't be rotated 360°.
Leaving the big locking knobs only to provide security for the final adjustment.

If you are a member of "The Other Place" you could start a topic on "CGE azimuth adjustment."
They seem to have have more Celestron CGE owners than over here. With several threads cropping up.
Unfortunately the countless examples of CGE user manuals online are all but identical!
None of them helped and the relevant drawing 2-10 [?] showed only the PA altitude adjustment.  :rolleyes:

As a final resort I'd be tempted to remove both, big black knobs and rotate the whole mounting to where it needs to be.
Then see how if it wobbles or moves around without the locking knobs.
You might even find additional screw holes hidden in the lower plate but I doubt it. Most users would never need them nor find them.
There might well be enough weight to hold it down securely on a fixed pier but you really don't want it "swinging around."
Don't lose the knobs! Such facilities are notorious for "helpful people" losing stuff over the years.
They could be an American thread form and irreplaceable locally except at highly inflated astro spares prices.

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7 hours ago, Rusted said:

I searched for ages about the CGE and found reference to a "socket head screw" in, or projecting from, the mounting top plate. Nothing visible on "yours?"
Later examples seem to have a worm, or threaded rod, fine adjustment in azimuth. A costly design solution unless you need it every night.

Owners complained [in another place] about the PA altitude adjustment being heavy but found the azimuth easy.
Presumably they could just rotate the tripod if they hit the end stops.

It really makes you wonder if the mounting was set up wrongly in the first place.
With no further azimuth adjustment possible because of the solid pier.
Even so I find it hard to believe they'd make a mounting which couldn't be rotated 360°.
Leaving the big locking knobs only to provide security for the final adjustment.

If you are a member of "The Other Place" you could start a topic on "CGE azimuth adjustment."
They seem to have have more Celestron CGE owners than over here. With several threads cropping up.
Unfortunately the countless examples of CGE user manuals online are all but identical!
None of them helped and the relevant drawing 2-10 [?] showed only the PA altitude adjustment.  :rolleyes:

As a final resort I'd be tempted to remove both, big black knobs and rotate the whole mounting to where it needs to be.
Then see how if it wobbles or moves around without the locking knobs.
You might even find additional screw holes hidden in the lower plate but I doubt it. Most users would never need them nor find them.
There might well be enough weight to hold it down securely on a fixed pier but you really don't want it "swinging around."
Don't lose the knobs! Such facilities are notorious for "helpful people" losing stuff over the years.
They could be an American thread form and irreplaceable locally except at highly inflated astro spares prices.

I'm honestly fairly certain the mount was set in the wrong place to begin with when they placed it.

I have removed both adjustment knobs and it still hits the limit, so it's something inside too that limits it.

The socket head screw is for fine adjustment for the azimuth turned by an allen key. It's located next to the locking screw on one side

I'm really not sure how to do this without taking the whole lot apart but hey, I'll figure something out

 

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On 14/10/2019 at 13:26, Davey-T said:

Remove one of these screws to see if the thread is in the outer part, if it is they may only screw into a groove to lock the top piece so loosening all three would allow rotation.

If the holes are plain and the thread is internal then it's a non starter.

Whatever it's not a one person job.

Dave

Did you check if these screws are thread into the outer surface or inner ?

Dave

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23 minutes ago, Davey-T said:

Did you check if these screws are thread into the outer surface or inner ?

Dave

The threads are on the inner orange plate

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Just now, matt_baker said:

The threads are on the inner orange plate

That's no help then, think you're going to have to remove the mount then the best bet would be to re-drill the pier base so it's aimed the right way with the azimuth pin aimed north/south rather than alter anything on the mount, that will future proof it for any other mount,

There are a few SGL members around your area so you may get a volunteer to help lift it off and back on.

Dave

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Looks like a dismantle job to me. All you need to do then is enlarge each of the three bolt holes on their left side so the whole lot can rotate enough to centre the azimuth adjuster.

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42 minutes ago, matt_baker said:

I'm honestly fairly certain the mount was set in the wrong place to begin with when they placed it.

I have removed both adjustment knobs and it still hits the limit, so it's something inside too that limits it.

The socket head screw is for fine adjustment for the azimuth turned by an allen key. It's located next to the locking screw on one side

I'm really not sure how to do this without taking the whole lot apart but hey, I'll figure something out

Let's keep trying before it finally comes to dismantling the whole lot with all the attendant risks to life, limb and expensive toys.

What exactly happens when you turn that socket head screw? Does the mounting move any further on in the desired direction?

It sounds as if it geared to the base somehow if it provides slow motion in azimuth. You only need a smidgen more movement in the right direction. 

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1 hour ago, Rusted said:

Let's keep trying before it finally comes to dismantling the whole lot with all the attendant risks to life, limb and expensive toys.

What exactly happens when you turn that socket head screw? Does the mounting move any further on in the desired direction?

It sounds as if it geared to the base somehow if it provides slow motion in azimuth. You only need a smidgen more movement in the right direction. 

I have a feeling its a gear or a cam

When I turn the socket it turns the mount in azimuth in slow motion. It won't budge at all when the limit's reached

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I think I've gathered at this point that the only solution to this is to take down the telescope and CW. Then loosen the centre bolt located underneath the pier plate at the bottom and see if we can move it a fraction.

 

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If it moves you might as well use a compass ( might be one on your phone ) and get it pointing north with the adjuster bolts central in their slots.

Dave

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I had an observatory mounted CGE for over 10 years so know a little about them.

Seems strange that an observatory mounted mount should be way out like this, has the mount, column, pier been messed about with recently?

If it has then running out of adjustment is possibly down to the pier not being put back right.

If not then check there isnt a nut or bolt or stuff dropped in the az slots. Easily done and will restrict the adjustment.

I,m trying to remember the orientation of the electronics column to the mount, I think its been put on in the wrong position. I need to check my old photos. The connectors on the column for the RA and Dec leads should be on the north, ish side otherwise the leads wont reach. I will post a pic of the correct orientation later

Edited by philj
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Hi Matt

Yep it looks like your electronics column is 120 degrees out, someone has had this apart and not put it back properly. The mount head may be pointing north(ish) but you will run out of adjustment. See pic of my mount in observatory. Your mount has non standard patch leads for RA and Dec motor cables which are longer than normal so this can happen. It wouldnt happen if you had the standard leads cos it would only go one way.

 

Oh, one would think that wouldnt make much difference as the holes are 120 apart but it will. Also there is quite a lot of play in each of the 6 column holes so when you have rotated the column to correct orientation you may get more adjustment on azimuth there.

 

Also please note using ordinary patch leads for the motor box RA and Dec leads is opening a whole can of worms, possible spurious slews, hitting the stops or motor errors, why? Because the celestron leads are earthed shells and ordinaru patch leads arent, many have tried and many have had problems. If these are earthed shell leads please ignore my comment but looking at your photos I suspect they arent. Note the leads shown on my mount are specials as I used the Canadian mod on the mount which came with special long earthed shell leads.

These mounts when working are superb but you have to iron out a few bugs before they are reliable. I loved mine but impending house sale meant it and the obs had to go.

PM me if you need any more tips, memory cells permitting I shall do my best to help.

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This is the cable mod I and many other owners did, you dont need it but if you have operational issues then theres some useful info in here. Gary is a mine of info on these mounts, I was close to getting rid of the mount with frustration at one tine, till I did this mod.

http://bendun.net/CGE-UPGRADE-KITS.html

So you may find that after sorting the PA you may have operational issues/ errors when you come to calibrate, if the leads are wrong.

Note, even if the leads are correct and an earthed shell, it doesnt mean all will be well. Sorry bout that. The rj45 sockets in the column are poor quality and give many problems, I remember unplugging and replugging many times trying to get the mount to calibrate. All sorted when I changed the rj45 for screw Din.

 

So you can probably see why these mounts get neglected in institutions, because it needs someone with dedication and time to sort them, something which schools and clubs cant seem to provide. They are excellent mounts and are superb on goto (5 calibration stars fir goto was very accurate pointing) plus for imaging they are good performers BUT

they arent simple to operate if your not used to them, download the manual before powering up for the first time and do some test calibrations in the daylight.

 

Oh and one final bit of advice, run from the handbox till you get used to it. Pc interface with nexremote can result in loss of hair, shouting and general depression 🙂

Edited by philj

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Update: 

Finally fixed it, just need to check next time it's clear and I'll polar align

Basically it was just a case of taking off the telescope and CW, then slackening off the centre screw that holds the mount down.

I turned it clockwise about an inch and kept the az bolts centred so there's a little bit of leeway to account for any error.

Thanks everyone for their help :)

Matt

 

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