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LX90 Tracking & Drift

lx200 sc lx90

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#1 Enceladus

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Posted 20 August 2013 - 06:17 AM

Hello,

I have recently purchased a new LX90 SC..Jan 2013. I have used the scope a number of times but I feel that the drift when using 'go to' is more than it should be. maybe somone could give there opinion.?

If I align the scope..either by setting north using polaris or the compass, when the scope is successfully aligned and I select 'go to' for e.g. a planet like saturn or the moon etc. the object drifts out of view quite quickly and also the movement is not smooth. eg. the object moves a bit then dwells then moves ..and so on. objects do not stay centred, even over short periods of say a few minutes. they quickly drift out of view.

I have used the telescope with both internal batteries and also a larger 12amp hr golf buggy battery and it makes no difference.

Is this kind of drift normal? as a novice am I missing something? can the tracking rate be adjusted manually to help keep objects centred?


Thanks

Nigel

#2 MistrBadgr

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Posted 20 August 2013 - 07:14 AM

Hello Nigel and welcome to the 4M Forum.

Since I do not have an LX 90, I probably should not actually speak up much, but I do not think what you are experiencing is normal.

One thing you can do that can often have some effect is to "train the drives." What this does is to let the scope learn, how much backlash there is in each of the gear trains, both altitude (vertical) and azimuth (horizontal). If there is more backlash (or slop) in the gears than the mount thinks, the scope can sit in one spot too long before the optical field starts moving with the sky. If the scope thinks there is more back lash than their really is, then the scope can seem to fight you when you try to move in a particular direction. Backlash is necessary to allow metal gears to move at all, and will change a bit over time as gears wear in. If the backlash is set too tight during manufacture, then there can be a jerkiness to the movement of the scope.

There is a routine in the scope for doing this. I believe it is discussed in your manual. The routine will guide you through the process. Generally this is done outside during the daytime, using some object as a reference that you center with the arrow keys as the scope moves away from the object in some specific direction. With little DS mounts, I normally like to go through the routine two or three times. I am not sure why, but things seem to work out better that way.

If the problems persist beyond training the drives, I would contact the store or company where you purchased the scope. In the US, people can contact Meade Customer Support, but there are contracts in place of various types in different countries. I cannot speak to those, other than to tell you to contact the people whom you bought the scope from when there are issues.

With that said, I am hopeful that training the drives will stop, or at least diminsh the trouble you are seeing.

As far as the moon goes, there may be a seperate lunar tracking rate. There is the normal sidreal rate for other things, but the Moon is a bit different. Since the Moon has a slightly eliptical orbit, its traveling rate through the sky varies a little bit. If there is a lunar tracking setup in your scope, it will be an average lunar rate. You may have to nudge the scope with your arrow keys occasionally to make the Moon stay put in your eyepiece.

Well, that is probably enough from someone who does not actually have an LX 90.

Hope this helps,

Bill Steen
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#3 Enceladus

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Posted 20 August 2013 - 07:51 AM

Hi Bill,

Thankyou for your response. I have not yet trained the drive but I will try that and see if things improve.

Kind Regards

Nigel

#4 Enceladus

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Posted 23 August 2013 - 01:05 AM

After training the scope twice. The image stays centered perfectly, even on the moon it stays central ..hardley any drift now. :)
  • Mark Sibole likes this

#5 MistrBadgr

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Posted 23 August 2013 - 05:03 PM

That is great! :) Just what we like to hear!
Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#6 Stevensteelman

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Posted 01 May 2014 - 10:28 PM

Hi Nigel, im a user of that scope and quite fond of it. Make sure that your target is set " astronomical" and tracking rate sidereal for stars or Lunar for moon. The scope will not tract if the target is set to terrestial.. Regards!
Stevensteelman





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