Tracking problem with Meade LX90 8" GPS

[davidscanlan]

Hi All,

I recently purchased a Meade LX90 8" GPS and it seems to have a tracking issue

I align without issue, daylight saving times are off, date and time is accurate. I slew to my desired object and its there in the centre of the FOV but it drifts!!!

Ive used new batteries and also used my juice tank but the objects still seems to move out of view....ive trained the drives used a star (capella) and have ensured the tracking rate is on sidereal

Not sure what else what to do.....any suggestions please?

Regards

Dave

[Bukko]

Hello, Dave,

I used to have an LX90; it was pretty fair holding objects, say, 250x magnification, it would take quite a while to drift out. But it still drifted.

You didn't say how much drift you are experiencing; is it slight (trying to image and getting dashes) or does it drift out of an EP FOV in quick order?

Having also mounted it on the Meade wedge, I wonder if your drift is because it thinks it is so mounted?

Possibly expecting too much from the mount?

HTH

Gordon.

[davidscanlan]

Hi Gordon

Thanks for your reply

The objects drift out of view quite quickly.....Ive checked im on sidereal tracking, astronomical not terrestrial, and still getting the same issues

Its becoming quite annoying

Regards

Dave

[Joves]

Hi Dave,

When you say you slew to your desired object, do you mean that you're automatically slewing after hitting enter on a desired object in the handset or manually slewing with the keypad directional buttons?

Aaron

[davidscanlan]

Hi Aaron

Thanks for the reply

I mean the scope automatically slews to the desired object, I get it in the field of view but then it starts to drift quite quickly

Dave

[stephen_usher]

Does your scope have the red-dot finder/levellr/compass  module? If this is out of alignment when you set up your 'scope then the system will not be able to work out how level the base is.

My Dad hs one of these on his 'scope and it causes more problems than it solves. It's better to use a spirit level to level the base and then the optical tube and a compass to point the tube nrth before powering up and aligning.

By far the most important thing to do when setting up to stop drift is to make sure that the tripod and base of the telescope are as horizontal as possible. I usually set the whole thing up and put a spirit level on the top of the base unit with the clutch undone so that I can rotate it freely and see that I have everything level in all orientations, adjusting the tripod legs as necessary.

[Davey-T]

As above, whilst GEM mounts aren't bothered by being a bit out of level I think fork mounts need to be level at least East to West, the mount is supposed to sense level etc but the better it is to start with the better.

Does it have a "calibrate sensors option" ?

Also the manual leaves a lot to be desired unless they've improved it.

Dave

[allen g]

go to the Astronomy Forum (sign in - no cost) there is a section pertaining to Meade and lots of fellow astronomers who have meads can give you good advice. I have that model - no problem - holds object quite well. I am certain there is something in the manual that addresses this issue. good luck.

[davidscanlan]

Hi

Yes it does have the red dot but to be honest I've haven't attached it. I've just using the standard finder

Would this be an issue ?

It does have the calibrate censors and I've done that

Out of interest. When I observe from local farmland it's harder to get aligned correctly and the signals on my phone are very poor. Would this mean that the gps signal is hard to get from here and is therefore not getting a good alignment?

[stephen_usher]

Hi

Yes it does have the red dot but to be honest I've haven't attached it. I've just using the standard finder

Would this be an issue ?

It does have the calibrate censors and I've done that

Out of interest. When I observe from local farmland it's harder to get aligned correctly and the signals on my phone are very poor. Would this mean that the gps signal is hard to get from here and is therefore not getting a good alignment?

The red dot finder is not only a finder but also an electronic level and compass. If connected then the alignment process will do extra operations as it will try to determine how level the base is.

Seeing as GPS uses satellites and not the phone system, your mobile signal has no bearing  on the issue. It could be that in the farmland the ground is less firm and the tripod legs could slowly sink into the ground, throwing your alignment out.

[davidscanlan]

Thanks

I'll install the lnc and let you know how I get on

Dave

[opticalpath]

Dave, try the scope on hard ground, or if on soft terrain, put a piece of paving slab or wood offcut under each leg to spread the load and prevent the feet from sinking in.

It's a long while since I used my Meade scope, but don't you get some confirmation message or beep to confirm that it has acquired the GPS signal?

Did you say if your scope is mounted alt-az, or on a wedge? 

Adrian

[davidscanlan]

Hi

Well ive installed the LNC and although the alignment has improved its still not 100%....objects are in the finder scope field of view, or very nearly, but the tracking of the objects do seem not to be tracking and the objects move out of the FOV as if there is no drives at all :-(

Ive got the scope on pavings slabs so I don't think sinking is a problem

The scope is mounted in ALT AZ

Ive calibrated the sensors, trained the drives (on Polaris), checked its on sidereal time, astronomical viewing and not terrestrial

I really am not sure what else I can do here....Im sure the issues are probably all my errors but I cant see what I am doing :-(

Regards

Dave

[opticalpath]

Dave, sorry to ask the obvious:

1. Have you checked that the RA and Dec locks are snug so the scope is not slipping.

2. Have you confirmed that the scope is actually moving at all?   Check this by setting it running then point it at a distant terrestrial object to find out if it's moving.  Or just note the scope's position and leave it running for an hour or two then look again to see if it moved.  If you confirm it's moving but just not tracking correctly, bring up the display on the handset that shows the scope's RA and Dec position (i.e. where the scope thinks it's pointing).   If it was tracking correctly, RA and Dec should hardly change.  Since your scope is not tracking correctly, they will change.  HOW they change (rate/ direction of drift) in each axis may tell you something about what is going on.

Adrian

[pavo]

Hi David

Are you still having this issue?

I had been having the exact issue some months back and it was driving me crazy.

When I did a GOTO to a target, the scope would go to it and then track it really well. However once it had landed on the object, if I manually slewed it, the object will then start drifting, to the point that it went off the FOV.

One day by mistake I pressed the MODE button after I had slewed manually, and hey ho, I heard the motors engage.

It seems that when you manually slew to an object (or move around), tracking mode gets turned off. To turn it back on, once you have the object in FOV (centered hopefully), just press MODE and tracking will start.

Let me know how it goes

Hope this helps

[NGC 1502]

Hi David

Are you still having this issue?

I had been having the exact issue some months back and it was driving me crazy.

When I did a GOTO to a target, the scope would go to it and then track it really well. However once it had landed on the object, if I manually slewed it, the object will then start drifting, to the point that it went off the FOV.

One day by mistake I pressed the MODE button after I had slewed manually, and hey ho, I heard the motors engage.

It seems that when you manually slew to an object (or move around), tracking mode gets turned off. To turn it back on, once you have the object in FOV (centered hopefully), just press MODE and tracking will start.

Let me know how it goes

Hope this helps

That's very helpful for your first post, welcome to SGL  sounds like you will be an asset here.

Regards, Ed.

[Davey-T]

Hi David

Are you still having this issue?

I had been having the exact issue some months back and it was driving me crazy.

When I did a GOTO to a target, the scope would go to it and then track it really well. However once it had landed on the object, if I manually slewed it, the object will then start drifting, to the point that it went off the FOV.

One day by mistake I pressed the MODE button after I had slewed manually, and hey ho, I heard the motors engage.

It seems that when you manually slew to an object (or move around), tracking mode gets turned off. To turn it back on, once you have the object in FOV (centered hopefully), just press MODE and tracking will start.

Let me know how it goes

Hope this helps

Just a refinement of the above, once you've manually centred you're target if you hold down the enter button for about three seconds you get a message "press enter to sync on target" then press enter and it tracks on that position (doesn't mention this in the useless manual)

Dave

[imk]

I have a meade lx90 8" EMC and have a very similar problem.

I have a NEW AudioStar and and have done several setup calibrations.

I level twice, first the tripod, then mount the scope and level the RA swinging it around and tweaking the legs, it is on hard patio. 

Couple of days ago i did extensive testing, with Easy alignment and then my own two star alignment.

Goto to was good moving from stars on the horizon to stars overhead and about a quarter of the guide scope width accurate.

When pointing at stars overhead there is no apparent RA drift, when point at stars on the horizon RA drifts quite rapidly! (about half width of a 15mm eyepiece in about a minute, stars drifts from middle to left side)

We are in north west UK, about  53 north 2 west 

Edited March 22, 2019 by imk

[PolarAligned]

Helping a friend to get started with a Meade LX90 GPS with the same problem.  Perform an 'easy' 2 star align and then able to use GOTO with reasonable accuracy to find another target. Problem is the target drifts at a speed suggesting its not tracking. Can still do another GOTO no problem but scope continues to drift. In short GOTO works but tracking doesn't.  Auto align doesn't work either in as much it asks to centre on the bright star but there is no bright star close (whatever star that is). Checked all the other settings and they are OK.  Can anybody with  experience of a LX90 GPS help please?

[michael8554]

I'd suggest that after a 2 year gap you should start a new topic.

Is the Setup / Telescope / Mount / Alt/Az or Polar mode set correctly ?

Is the Setup / Telescope / Tracking Rate set to Sidereal ?

Is Setup / Targets set to Astronomical ?

Although it doesn't sound like you have this problem, an unrelated problem with GPS scopes - is the year the GPS is offering correct 2021 ?

Michael