LX200 tracking

[BigJ]

I'm having some problems with the tracking on my LX200. It just seems to drift away quite quickly from whichever oject I am viewing.

I haven't been using it long, so this is almost certainly due to the way I've set it up, which is causing it to track in the wrong direction. In particular, I think it must either be the site location or time setting, causing it to think it is viewing the stars from another part of the globe, or another part of the day.

Could this simply be caused bu a one-hour's difference if I haven't changed the time setting after daylight savings?

Regarding my current settings:

Site Location:

If I'm in Bondi (lat -33.888408, long 151.270334), then do I need to enter longitude as 208 degrees 44min?

Time setting:
Should this be set at -10 hours?

All suggestions appreciated.

[marki]

Hi

What sort of LX200 is it? Classic, GPS, R or ACF? I own the R version which comes with GPS and automatically downloads time and location from several satillites. I always set the daylight savings to off and the scope sets itself using UT. If you set the location manually you should have a choice of locations of the nearest cities to you in the software under select location, just pick the right one or type in your coordinates as given by google earth or a good map. Make sure the time you set is local time e.g. am/pm option and you should be right. Align on stars either side of the meridian using a high power eyepiece (9mm illuminated retcle is best) and Bob's your uncle, it should be good to go. Also it pays to update software on the controller from the meade site if you have the chance.

[renormalised (Carl)]

Time zone setting = +10 hours

Lat and Long for Bondi, as is (except convert to º ' ")

Location = Bondi, NSW, Australia (make sure that's entered into Autostar)

daylight savings time entry = turn it off.

Then run a full align with a two star alignment.

Also it pays to update software on the controller from the meade site if you have the chance.

VIP!!!!!!

[[1ponders] (Paul)]

A couple of clarifying questions.

How quickly is "drifts away quite quickly"?
What FL eyepiece and FL of the scope?
How long does it take a star to go from one side of the eyepiece to the other?
Do you have your scope on a wedge and in polar mode or not on a wedge and in basic Alt/Az mode?
Have you checked to see that you are in sidereal tracking rate and not terrestrial or luna?

[rogerg (Roger)]

Also, do you know what direction it's drifting ? Ie, which button (N, S, E or W) do you have to press to compensate for the drift?

[renormalised (Carl)]

Good questions which should be asked, because if that drift is happening quickly in a low power eyepiece, then there's definitely a problem.

[thunderchildobs]

On Classsics, there is a N/S switch on the control panel, near the power switch.

It is easy to change the N/S switch when you are trying to turn the scope on /off.

Brendan

[space oddity]

Sounds like the drives need training. This should be done every 3 to 6 months. It is a daylight task .You will need an object at a decent distance away to train the drives in RA and Dec and a reticle eyepiece to make sure that you get exactly back to the reference point. Also very important to centre the 2 stars at alignment as accurately as possible. Another possibility for problems is selecting polar mode instead of alt/az mode. Hopefully it is not an actual motor problem.

[BigJ]

Thanks everyone for being so willing to help out.

OK, to answer all our questions in order:

- marki: It's a classic, so no GPS and no fancy daylight savings options!
- renormalised: I'm not sure whether "Lat and Long for Bondi, as is" means that longitude should be set as 151 degrees or 208 degrees...
- Paul: (1) I didn't time it (I wish I had!) but I would say a star would drift from the centre of a 12.5mm eyepiece to the edge in _about_ 15 minutes (very approximate). The FL of the scope from memory is 1280mm (2) It's not on a wedge and in alt/Az mode. (3) I believe the tracking is (or was) sidereal but I'll check.
- Roger: I remember seeing in the finder scope, the stars that had previously been aligned on the cross hairs had drifted to the right hand side, slightly lower down. Since the finder scope image is both upside down and back to front (I think), I guess this means the scope moved too far to the left (and up a tiny fraction).
- Brendan: I may be a bit of a novice, but the N/S was the first thing I thought to check. Unfortunately it was set on "S" :-)
- Space Oddity, This seems like a more fundamental problem than training the drive.

I'm pretty sure it was set on the sidereal tracking but I'll check, and I'll try to measur ethe exact direction and extent of the drift.

Unfortunatel yI don't have an I.R. eyepiece but I'll do my best.

Meantime can anyone confirm the question about longitude?

Thanks everyone. What a great bunch...!

[BigJ]

Renormalised: The manual says if you are east of Greenwhich then you should be MINUS...

Maybe that's where the problem is...?

[BigJ]

OK, the setup APPEARS to be correct, in that the sidereal time (which is worked out from the geographical coordinates and the hours from GMT) showed the same value as that on the website http://www.jgiesen.de/astro/astroJS/siderealClock/ when set for Sydney.

What is strange is that I was unable to align the scope using Antares (almost at azimuth) and Spica, using 2 star alignment. I got an alignment mismatch error even though both were spot in on my 6mm EP. Then I went to Jupiter, confirmed the coordinates, and it was then unable to find Antares accurately...

[renormalised (Carl)]

Bondi is around 151º East....208º would put it over the dateline and actually 152º West, which would be wrong. Not only that, all time zones east of Greenwich are ahead of there and therefore "+", so that manual is wrong.

[BigJ]

Maybe that's the problem then. But doesn't 151 degrees East correspond to 208 degrees west?

[renormalised (Carl)]

Originally Posted by BigJ

Maybe that's the problem then. But doesn't 151 degrees East correspond to 208 degrees west?

No!!!....there's no 208º of longitude anywhere on the planet. You can go either 180ºE or W, nor more and no less.

[BigJ]

That was my understanding too, originally. But in the manual it says:

It is important to note that the longitude standard used in the
LX200 starts at 0 degrees in Greenwich U.K. and increases
Westerly only to 359 degrees 59 minutes. Many maps will show
Easterly longitudes which cannot be entered into the keypad
display. As an example, if your map indicates that you are at an
Easterly longitude of 18 degrees 27 minutes, then you would

enter 341 degrees 33 minutes.

[renormalised (Carl)]

That's screwball!!!!

I suppose whoever wrote that manual also says there's 400º in a circle!!!!

Don't know what universe they come from, but it ain't this one!!!!

I'd say the meaning of lat/long and the values were lost in the translation somewhere!!!. If it can run the new software and controller, get the new Autostar and ditch the old one. Then update the software. You may have to goto the Meade forum to find out if you can, but I think you should be able to.

[renormalised (Carl)]

It'll probably mean you'll have to run a firmware update on the controllers in the base of the Meade, but that won't be too demanding.

[thunderchildobs]

1)Have you tried wringling the cable where the cable joins the handset and the control panel. Do this with the power off. There might be a bad connection on the pins.

2) Try swapping the cable between the handset and the control panel around.

3) try using a different cable if you have one.

4) try using a different handset, there might be a NSEW key which is stuck down.

5) Is the clock working? I have found that due to flat internal battery, the clock wasn't working on start up. There was a drift of about 1 sec per sec in RA. Restting the clock, the problem disappeared.


Brendan

[rogerg (Roger)]

Originally Posted by renormalised

If it can run the new software and controller, get the new Autostar and ditch the old one.

You can't put an autostar controller into a classic LX. Only the classic LX HC (hand controller) will work. Absolutely no doubt about that.

Not relevant here I don't think, but it is possible to buy new ones, through BINTEL, not Meade.

Originally Posted by renormalised

It'll probably mean you'll have to run a firmware update on the controllers in the base of the Meade, but that won't be too demanding.

The only firmware update you can do with the LX200 classic is by taking out the two EPROM chips, using a chip-programmer to re-write their memory, then putting them back in. To get the latest firmware version which was made (4.31) you need to know someone who has it and is willing to give you a copy, meade will not give you a copy and will not admit there is anything newer than 4.30 available. It would be interesting to see what version you have (it says upon start-up) but I doubt it's your problem unless you recently bought the scope from someone in the northern hemisphere, then it's a chance.

Originally Posted by BigJ

- Roger: I remember seeing in the finder scope, the stars that had previously been aligned on the cross hairs had drifted to the right hand side, slightly lower down. Since the finder scope image is both upside down and back to front (I think), I guess this means the scope moved too far to the left (and up a tiny fraction).

At a guess it'd be RA error you're seeing then? With the hand controller, press mode until you get to the screen with RA and DEC. When you are not pressing anything, and it's not (in theory) slewing, are RA and Dec steady? They'll flick around a tiny bit, but are they basically sit steady, unless there's a problem. If one is moving, particularly RA, you have a hardware fault of some kind. If they're steady, I think your problem is more likely to be fixed by polar alignment, PEC, and perhaps changing the tracking frequency, which is configurable via the hand controller (will help more with that if we get to it).

I'd be interested to hear if your RA and Dec readings on the HC are staying steady or not (as per above).

Roger.

[renormalised (Carl)]

Originally Posted by rogerg

You can't put an autostar controller into a classic LX. Only the classic LX HC (hand controller) will work. Absolutely no doubt about that.

Not relevant here I don't think, but it is possible to buy new ones, through BINTEL, not Meade.



The only firmware update you can do with the LX200 classic is by taking out the two EPROM chips, using a chip-programmer to re-write their memory, then putting them back in. To get the latest firmware version which was made (4.31) you need to know someone who has it and is willing to give you a copy, meade will not give you a copy and will not admit there is anything newer than 4.30 available. It would be interesting to see what version you have (it says upon start-up) but I doubt it's your problem unless you recently bought the scope from someone in the northern hemisphere, then it's a chance.




At a guess it'd be RA error you're seeing then? With the hand controller, press mode until you get to the screen with RA and DEC. When you are not pressing anything, and it's not (in theory) slewing, are RA and Dec steady? They'll flick around a tiny bit, but are they basically sit steady, unless there's a problem. If one is moving, particularly RA, you have a hardware fault of some kind. If they're steady, I think your problem is more likely to be fixed by polar alignment, PEC, and perhaps changing the tracking frequency, which is configurable via the hand controller (will help more with that if we get to it).

I'd be interested to hear if your RA and Dec readings on the HC are staying steady or not (as per above).

Roger.

I thought not...that's why I said "If". Now that is inconvenient...do they still sell EEPROM programmers at Jaycar or "Shmicky Dickies" (Dick Smith's)?? I would imagine the latter still holds them in stock. But like you said, Meade isn't going to cough up the new firmware.

I was thinking he may have slack gears and might need to tighten them up a bit. Hopefully not worn gears....didn't Meade withdraw their maintenance kit from sale?? Pity.