Unable to stop goto on CG5

[Jinx]

Hi folks, on my third ever viewing session (last night) I mounted my explorer 250p onto my CG5 goto mount, and got ready for an evenings viewing. As yet I have not used the goto preferring instead to star hop initially so haven't bothered with polar alignment.

However when viewing Jupiter, I accidentally hit goto for a messier object when attempting to maintain Jupiter in my field of view. Before I knew it the scope was turning round and down, and I was unable to stop it while I watched the motor push one of the clutch release catches into the side of the motor housing and snap the lever off.

To add insult to injury, it happened a second time, with me accessing a goto whilst fumbling with the handset to track to Betegeuse, :BangHead:but I managed just in time to pull out the power cable.

Is this just me, :dontknow:has it happened to others, can you get replacement clutch levers, and how do I prevent it happening again.

Is there a starting orientation of the mount and tripod, that would prevent this ever happening again?

I suspect that I am being very thick and apologise in advance, but please can someone put me straight.

Alec Jenks

[Kai]

What make of mount do you have ?

Did you do a "Goto Alignment" before using the scope (not Polar Alignment) ?

If not then i suspect that the error is / was down to the fact that the scope doesnt know where its orientated so when you pressed the button it just slewed to where it thinks the object is, in which case then im afraid its user error .

I would of thought that you would be able to source the snapped levers from the relevant importer.

[Jinx]

Oh I totally admit it was user error, but I was wondering if I would have to align every time to prevent this happening even if I am just manually scanning the sky.

The mount is the Celestron CG5 with goto, and I am not sure how when the motor is in full swing to cancel a goto despite having read the manual.

Also am I alone in this problem?

[Capricorn]

The first paragraph says you have not yet used the goto so I presume that the scope had not been aligned at all.

Hitting goto in this case will means that the scope could slew anywhere, it will not know where it is pointing and whatever data present will be completely irrelevant to where you were pointing. Where the scope tried to slew to could be anything and your mount was in the way.

The system in effect had the command goto XXX and it did, your clutch was in the way.

Puzzled how you managed to get a Messier on the handset and press the gotp option. On mine it is more then a simple press of the wrong button, a selection of the object type has to be made then a selection from that, then the go button. It takes about 3, if not 4, seperate buttons to get the thing to goto anything. It is one of the things that annoys me a little.

If you do align it and use the goto option then you have to keep using the goto or not use it again for that session. If you goto say M42 then start manually moving and then decide to use the goto afterwards, the scope will still believe it is pointing at M42 and will slew to the requested new goto object as if it were at M42. So again the mount will be at risk, as will the scope.

[Cornelius Varley]

You do need to align the mount to prevent this happening. The handset assumes the starting position is counterweight down and the telescope pointing towards NCP, it also assumes that the date, time and coordinates are all correct. From this info the handset can map the location of the celestiql objects. If you accidentally press a button and the mount has not been aligned it will slew off in the direction it thinks is correct.

Peter

[Kai]

Im sure that you do not need to align IF you are just scanning the sky , but if you do press goto by mistake the mount will only do as commanded.

I would suggest that you make Goto aligning part of your setup routine to prevent accidents happening in the future . The issue is that you will still have to be aware for any clashes whilst slewing.

IIRC Celestron alignment just involves pointing the scope at 2/3 bright objects after pointing the scope at Polaris so isnt too involved.

[brucen]

If it happens again can you not just pull out the power lead and stop it moving that way?

[continuum]

Probably the best thing to do is thoroughly read the manual and follow the instructions there. If you don't have the manual, download it from the Celestron website. I know men are not supposed to read instructions but it really does help.

RonJ

[Kai]

If it happens again can you not just pull out the power lead and stop it moving that way?

On my AWR Handset all i have to do i press one of the arrow buttons to stop the scope slewing , not sure if its the same with Celestron.

[Psychobilly]

Yep any arrow key will do it onthe Celstron Nexstar controllers...

This is from the Celestron Website FAQ's

Question

How do you stop a GOTO slew in progress? Is there a better way than turning off power or pulling the power plug?

Answer

Interrupt the mount’s GOTO slew by pressing any arrow key. The mount will halt the GOTO in progress.

Since this is a regular hand control function, no alignment or other information will be lost as it would be if you stopped the mount by powering it down.

Peter...

[Stu]

Same on my star book. Basically hitting any button stops it slewing. As has been said, check out the manual, I'm sure there will be a simple way to stop slewing as there is a risk of damage as you have discovered

Hope you get sorted and damage is easy to repair

Stu

[G6RAR]

Hi Alec,

It may not be a GoTo that is happening.

Have a look here on the Nexstar Resource Site.

http://www.nexstarsite.com/OddsNEnds/ASGTRunaway.htm

Also this page covers the power side of things

http://www.nexstarsite.com/OddsNEnds/PowerSources.htm

Note the comments ref the size of the power connector.

Hope you get it sorted out.

Cheers

Dave

[Jinx]

Thanks all for the replies, I do feel a complete numpty over this, but having read the article on runaways, I checked the lead and connectors, finding them absolutely filthy in the process. Just for your information the arrow keys definitely did not stop the slew - I was hammering on them whilst making strangled sounds / pleading with it to stop. This could well have looked a sight in a deserted field in the middle of the night!

Anyway, time to source a new cclutch lever and hope that my shiny contacts have sorted it.

Once again, thanks all...

[G6RAR]

Alec,

Don't feel a numpty at all.

When it happened did the display on the handset say "Error 17"

If so this indicates a loss of communication to the main board in the mount, can be caused by intermittent power disconnection in the plug.

If so, then no amount of button pushing would stop the mount from slewing to possible destruction.

A friend of mine with a CG5-GT has the same problem and he tapes the power cable so it can't move. He also has a similar problem if he holds the handset.

So the handset stays in the holder all the time and it works well.

Hope you get it all sorted as the accuracy on the CG5-GT is superb.

Dave