Meade LX90 Goto not tracking!

[Draco (Draco)]

Originally Posted by AndrewJ

Gday Niv

What firmware version is loaded??
What are you backlash settings set to?

In altaz, you can slew using the hand control after a goto to any object and it should keep tracking. The only time it ( normally) drifts after aligning is if the backlash isnt applied correctly/quickly enough on reversing.

Andrew

Hi Andrew
Where do I get these information from? I think I have seen it somewhere under setup on the hand controller? Will need to go through the options and have a look and report back

[Draco (Draco)]

Originally Posted by julianh72

As Andrew says:
How long did you wait before concluding that the tracking wasn't working after manually driving to a new target?

If I recall correctly, when we first set up my father's LX90, it would sit still (apparently) for about 15 seconds or so after manually driving it to a new target (depending on which directions you approach the new target from), and then the tracking would pick up again. At high power, the target would often drift out of view before the scope started tracking again.

I think we needed to re-set the backlash settings (Alt Percent and Az Percent - see page 28 of the user manual), and now it tracks pretty well instantaneously at all times, whether manually driven to a target, or using the GoTo functions.

Hi Julian

Thank you for your reply. I think I waited for around 10s before concluding it wasnt tracking. I will again tonight and wait for at least 15sec. Yes at high power the object just zooms by

BTW do you remember what value you set for the alt and az percent?

Thank you

[AndrewJ]

Gday Niv

The firmware version will appear on the Hbx during booting, and otherwise its under the statistics menu.
To read the lash percentages via the hbx, go to the setup > telescope > backlash section.
Basically, if you have a drive train value of 100 arcsecs, it means that when the scope changes direction, there is 100arcsec of slop in the geartrain that must be taken up before it starts moving again.
The percentage values tells the scope how much of this to apply at high speed, so what people normally do is start at say 90 and just try the buttons.
If it "jumps" in the EP due to a bit of overrrun when you press the buttons, just drop it to 80 and try again.

Andrew

[Draco (Draco)]

Hi Andrew

The firmware from statistics is A1F7 (though when the controller boots up it shows 497EP A1F1, is this the same?)

AZ/RA Ratio = -2.75074482
ALT/DEC Ratio = +2.75074482
AZ/RA Percentage = 10%
ALT/DEC Percentage = 10%

I couldn't find any settings under drive train except that it started asking me if i wanted to train the drives

Are these settings acceptable? Also is that the current firmware? I was told by Bintel that they dont install the firmware from Meade but from another site, which contains fixes for the meade firmware done by some guy. Forgot the name sorry

Originally Posted by AndrewJ

Gday Niv

The firmware version will appear on the Hbx during booting, and otherwise its under the statistics menu.
To read the lash percentages via the hbx, go to the setup > telescope > backlash section.
Basically, if you have a drive train value of 100 arcsecs, it means that when the scope changes direction, there is 100arcsec of slop in the geartrain that must be taken up before it starts moving again.
The percentage values tells the scope how much of this to apply at high speed, so what people normally do is start at say 90 and just try the buttons.
If it "jumps" in the EP due to a bit of overrrun when you press the buttons, just drop it to 80 and try again.

Andrew

[AndrewJ]

Gday Niv

The firmware from statistics is A1F7 (though when the controller boots up it shows 497EP A1F1, is this the same?)

Yep, thats good and its the best firmware for what you are doing

I couldn't find any settings under drive train except that it started asking me if i wanted to train the drives

If BINTEL loaded the patched firmware, you should now have 4 entries under drive train. The last 2 will be something like RA= and DEC=
Hitting enter on these will allow you to read/edit the drive train values direct from the Hbx.
Other that that, you can use my PEC editor to read a lot more of the data out via a PC connection.
http://members.optusnet.com.au/johansea/ ( grab the beta copy at the bottom )

Are these settings acceptable?

The 10% lash may be too low, but we need to know what the drive train numbers are as well, as the two work in conjunction.
The drive train is done first to define the magnitude of the lash.
The percentages are then tweaked to improve the "responsiveness" of reversals.

I was told by Bintel that they dont install the firmware from Meade but from another site, which contains fixes for the meade firmware done by some guy. Forgot the name sorry

A1F7 is actually Meades firmware, but third party patches are then applied to fix a lot of the known bugs. I am the "name" who did the patches for the Audiostars )

Andrew

[Draco (Draco)]

Hi Andrew

I will check the settings tonight when I am home and post the values.

Thank you for the link to the PEC editor. Will definitely give it a go. BTW how do I connect the Hbx to my computer to use the editor? Sorry noob question . Also am I able to use this software to control the slewing of the LX90? If so then how would I connect the laptop to the LX90?

Hey Andrew, didn't realise that you were the "name" who did the patches. Everyone at Bintel talks very highly of you. I am privileged to be communicating with you. Thank you for all the awesome work you do mate.

[julianh72 (Julian)]

Originally Posted by Draco

AZ/RA Ratio = -2.75074482
ALT/DEC Ratio = +2.75074482
AZ/RA Percentage = 10%
ALT/DEC Percentage = 10%

If I recall correctly, I think we changed the AZ and ALT percentages to 50%, and that pretty much sorted out the backlash lag for my father's LX90, so we didn't tinker any further.

It's easy enough to edit the values and test it out, and if you somehow get it totally scrambled, you can always revert to factory defaults and start again. (We took a note of all settings for just such an eventuality, or if the handset ever needs to be re-flashed, etc, but we got it sorted to our satisfaction in a couple of minutes.) His telescope is used solely for visual use, so we weren't looking for ultra-precise tracking, but we wanted to get rid of the initial drift / lag after driving to a new target.

[AndrewJ]

Gday Niv

BTW how do I connect the Hbx to my computer to use the editor?

You need a serial port or a USB2Serial adapter first.
Then you need a cable wired up to suit the Meade format.
You can buy these ready made or make one up yourself.
Very simple and wiring diags are available if reqd.
Once you have that cable, you can connect anything to the Hbx, like planetariums, updaters, my editor, autoguide programs etc.

Also am I able to use this software to control the slewing of the LX90

My editor has a full remote control handbox so anything that can be done from the hbx can be done from the app. It also has two special dialog boxes that allow you to do drive train testing etc using a separate webcam feed. Much quicker and more accurate than the Hbx method.

Hey Andrew, didn't realise that you were the "name" who did the patches.

I am the second in the list. A chap called Dick Seymour did the original patches for the 497s and deserves the bulk of the credit. I learnt off him and then extended his work as well as did the patches to the newer 497EP/Audiostar Hbxs, ( as they use different processors to the std 497s ). ie its a joint effort.

Andrew

[Shano592 (Shane)]

Hi Niv,

Just a quick question ...

When you used the arrow keys to centre your target, did you then use the handbox to re-confirm the object?

I'm speaking from my experience on the LX200, but what I do is this (after your regular 2-star alignment of course) ...

Once you are happy with the position of the desired object in the eyepiece, you press and hold GOTO for about 2 seconds. It will ask you to confirm, so you press it again, and it tells you that it is ok.

That's how I align on an object on my scope anyway. I do it as a force of habit now. Every adjustment with the arrows keys gets a manual update from me.

Good luck - I hope you get this sorted.

[Draco (Draco)]

Thanks Andrew.

I will try getting a usb2serial adapter and then will go forward from there.

Is that software just for Windows or is there a version for Mac as well?

Thank you.

[Draco (Draco)]

Hey Shane

I didn't know about that feature. I know that if the GOTO takes you to the object and it is not in the center, I can use the arrow keys to get it in center and then press the ENTER key for at least 3 seconds and it then asks me to press ENTER again to synchronize. This basically corrects the GOTO algorithms if they dont accurately take me to the object. Is this what you were referring to? I will definetely try pressing GOTO when I have the scope out next.

My issue is not of the GOTO (which works really well and gets me to the object). it is more about me trying to manually going to an object but the telescope does not track it. So as soon as I get to the object, instead of it being steady in the field of view, it starts drifting and I constantly have to press the arrow keys to keep it in view. last night I tried waiting for at least 20s for the tracking to kick in but it didnt

Originally Posted by Shano592

Hi Niv,

Just a quick question ...

When you used the arrow keys to centre your target, did you then use the handbox to re-confirm the object?

I'm speaking from my experience on the LX200, but what I do is this (after your regular 2-star alignment of course) ...

Once you are happy with the position of the desired object in the eyepiece, you press and hold GOTO for about 2 seconds. It will ask you to confirm, so you press it again, and it tells you that it is ok.

That's how I align on an object on my scope anyway. I do it as a force of habit now. Every adjustment with the arrows keys gets a manual update from me.

Good luck - I hope you get this sorted.

[Draco (Draco)]

Hi Andrew

Under Drive Train I dont have RA= and DEC= but instead I have AZ= and ALT=
When I go into these,the values are
AZ/RA Train = 61
ALT/DEC Train=10

Thank you

Originally Posted by AndrewJ

Gday Niv


Yep, thats good and its the best firmware for what you are doing


If BINTEL loaded the patched firmware, you should now have 4 entries under drive train. The last 2 will be something like RA= and DEC=
Hitting enter on these will allow you to read/edit the drive train values direct from the Hbx.
Other that that, you can use my PEC editor to read a lot more of the data out via a PC connection.
http://members.optusnet.com.au/johansea/ ( grab the beta copy at the bottom )


The 10% lash may be too low, but we need to know what the drive train numbers are as well, as the two work in conjunction.
The drive train is done first to define the magnitude of the lash.
The percentages are then tweaked to improve the "responsiveness" of reversals.


A1F7 is actually Meades firmware, but third party patches are then applied to fix a lot of the known bugs. I am the "name" who did the patches for the Audiostars )

Andrew

[AndrewJ]

Gday Niv

When I go into these,the values are
AZ/RA Train = 61
ALT/DEC Train=10

OK, i have not seen numbers that small for an LX90 before, and may indicate you are undertrained, which would explain your drift as well.
How did you do your drive training ????
ie where was the target and how accurately did you centre it??


Andrew

[Draco (Draco)]

Hi Andrew

I have never done a drive train myself
Bintel had done it for me when I had taken it in for the drifting issue. I dont know if it was done outside, under the majestic night sky or inside

Is it easy to do a drive train? I can attempt it in the weekend if the weather is good

Thank you

[AndrewJ]

Gday Niv

Drive training is simple and is a skill to learn, as its a general maintenance type operation, like collimating etc.
It is easily done during daylight hours as all you need is a high powered eyepiece ( preferably with a crosshair ), or a webcam feed if you use my app to do it, and a stationary target a few miles away if possible. The further the better.
I actually set up inside my house at times and view out through an open window if the weather isnt to good.

That said, if BINTEL did it, i would expect it to be correct, but the numbers just seem extraordinarily low compared to what i have seen before ( esp the 10 ).
If you write down the current numbers, you can then try a few drive trains yourself, and see what sort of numbers you get back.
At the end, you can always use the Hbx to manually reset them if required.

Andrew

[Draco (Draco)]

Thank you Andrew.

Just for my own reference, what numbers are normal for RA and DEC?

Thank you for all your help.
Regards

[AndrewJ]

Gday Niv

LX200s with good gearboxes normally return about 60-75
most LX90s i have seen data on were 80-150
ETXs can get up into the multi hundreds if the geartrain is really sloppy

Andrew

[Draco (Draco)]

Hi Andrew

Seems like almost a month since I updated you on what I did last with the scope in trying to resolve the non-tracking issue. I re-trained the drive at least 5 times but I still haven't been able to resolve the issue of it not tracking the object when I use the arrows to move to an object, after the telescope has GOTO'd to something.

I have a question which you might be able to help me answer. I know that since the stars/constellations/galaxies are so far away, that their actual movement, relative to us, can be taken as negligible. In this case, the perceived movement of these celestial bodies is due to the rotation of the earth. However with the solar system objects, they are closer so their movement is noticeable, hence their movement across the night sky is actually a combination of the earths rotation and their actual movement relative to earth?

Now if I GOTO to an object and then use the arrow keys to move to another, I assume if this other object is not a solar system object then its movement across the night sky will just be due to the rotation of the earth, in which case if the telescope tracks on sidereal mode, it will keep the object in the field of view. However, if the object is a solar system object, then its movement will be not just sidereal but its orbit as well, in which case if the telescope is tracking just sidereal, it won't be able to keep the object in the FOV unless it knows what object it is? Please correct me if I am wrong since I am just blabbering out.

However since the LX90 has got a lot of objects in its database, one could expect that as soon as the arrows have been used to get to an object, the LX90 will search its internal database to find out what object is currently in the FOV (using the RA and DEC) and then use the appropriate tracking speed to keep it in FOV?

Can you please do me a favour. Assuming you have a LX90, can you please GOTO Saturn. Once there, use the arrow key to move just one step any way or maybe just bring one of the moons into the centre of FOV. After doing this, do you see Saturn and its moons start drifting out of FOV? Assuming that it takes x seconds for your LX90 to correct itself, after x seconds, do you see Saturn and its moon return into FOV and the FOV show what it showed when you had used your arrow keys to go to something else?

Thanks mate and hope your weekend has been great.