Meade LX90 Goto not tracking!

[Draco]

Hi all

I have a 10" Meade LX90 ACF. Last night I took it out to view mars and wow what a sight it was. One of the poles was whiter than the other, though smudgy, I assumed it to be the ice caps.

Initially I used a 30mm eyepiece and though it was a less magnified image, things were still quite clear.

Then I changed to a 10mm eyepiece and to my dismay, mars shot through the viewing diameter in less than 10s.. Well it seemed around 5s. I had put mars on one edge and by 5s it had moved to the center and out of view.

I always thought that gotos would track an object, after I have put it into view. I do realise this is a planet so has more movement than the normal sidereal rotation of stars, but i had set my goto to target astronomical objects.

Is this expected behaviour or have I done somethig wrong in one of the settings?

Would appreciate all the help I can get. Btw I am unsure if this happwns in lower power since didnt check, however it could be more subtle in that power if it did and I will need to spend more time to see if it is happening

Thank you and happy mars viewing

[mental4astro]

You sure you followed the correct set-up proceedure for the mount? By what you are describing, there is NO tracking happening at all.

[Draco]

Hi Alex

Actually I don't remember doing any set-up procedure for the mount. I had basically started using it as soon as I got it :( So yea my bad.

Do you know how I can set it up?

Thank you

[Merlin66]

It should all be covered in the Instruction manual.....

[jenchris]

I'm sure you missed something in the setup (especially if you didn't actually do one)
Once you have explored all possible problems, read the instruction manual.....
D'oh!

[Draco]

Thanks JenChris. I guess its a simple case of http://en.wikipedia.org/wiki/RTFM ;)
(http://en.wikipedia.org/wiki/RTFM)

[Draco]

Hi Guys

Checked the manual online and I am doing everything as expected. Will give it a go tonight again and if all fails, will take it to Bintel since it is still under warranty.

Thank you all

[38degsouth]

Hi Niv -PM me if you'd like a basic setup run-through in simple point form. I run an older 8" LX90 for visual observing in alt/az configuration. Best of luck with getting your 'scope running and tracking. :) Regards, Dean

[AndrewJ]

Gday Niv

Are you Polar or AltAz?
Have you done a drive train?
What Fimware version is loaded?
After fitting the 10mm, did you have to use the slew keys to recentre Mars?, and if so, what speed was the Hbx set at when you slewed?
If it is drive train related, the system may "appear" to stop tracking whilst the gears are reversing after you slew against the tracking direction.
ie it may take 10secs for the OTA to actually start moving again, depending upon how much slop is in your drive train.

Andrew

[Draco]

Hi Andrew

Thank you for your response.
My scope is in Alt/Az (no wedge, just the standard mount)
havent done a drive train :(
I will boot the system up tonight and get the firmware version
yes, after putting the 10mm, i did have to use the slew keys. I think I used the digit 2 or was it 4. Dont know what speed that comes out as

Once I had changed eyepieces and used the audiostar to retarget mars, i used the slew keys to get mars in the center. however it just went through the field of view and out. I must have waited another 5 - 10 seconds to see if it came back into view but it didnt so I used the slew keys again to get it into view. All the time, while I wasnt doing anything, the motor in the mount was buzzing away, guess it was doing something but not the right thing?

If it makes any difference, I saw mars go from bottom left of the scope, diagonally to the top right. From memory, ACF/SCT have their left/right reversed so that would mean that mars was in actuality moving right bottom to left top, which would be what was actually happening. Does this mean that either my mount was not doing anything or wasnt fast enough to counter mar's movement or worse yet, it was going in the opposite direction to mars movement? (sorry too much caffeine.. cant think straight.. am uttering gibberish.. will end now)

thank you

[Merlin66]

Sounds like you need to set-up the "tracking" option....
Follow the procedure outlined on p17/18 of the Instruction manual to set up the Autostar controller.

[Draco]

Hi Ken

Thank you for your response. I already tried instructions on those pages, but didnt help :(

Regards and thank you

[Merlin66]

Hmm
When looking at a distant object...is the mount tracking? i.e. the telescope actually moves...
RA lock?
Batteries Ok?

[julianh72]

Draco,

I'm confused - did you, or did you not, start the evening's viewing with a "Two-Star Easy Align" as set out on pages 18-20 of the user manual http://www.meade.com/software-manuals/telescope-manuals/lx-series?download=6:lx90-manual ? (Page numbers are for Meade manual ref. 14-6700-21 rev001 07/12 - see the last page of the manual to see if we're using the same document.)

In this post you say you are doing it all "as expected", but in an earlier post, you said you "don't remember doing any set-up procedure for the mount". (You would remember aligning the telescope if you had done it. If you never saw the "Alignment Successful" message on the handset, you have NOT aligned your mount.) Once you have gone through the initial alignment procedure a couple of times, it only takes 2 - 3 minutes to get your scope aligned each time you set it up.

If you skip the two-star alignment procedure, you can drive the mount as a dumb powered Alt-Az, but it won't track stars, or GoTo targets. (I guess the telescope controller "assumes" that it started the night in the "Home North" orientation, or some other default orientation, so will drive the motors accordingly, but the tracking speeds will be all out of whack if that was not the case.)

Once you have done the initial alignment, you can GoTo any target in its database (or manually enter the coordinates), or just manually drive the scope around using the handset controller buttons (DON'T release the clutches to manually slew the scope!), and it will track whatever you stop on once you release the drive control buttons.

[AndrewJ]

Gday Julian


Not quite true. If you start the scope as AltAz when it is pointing North and level, and enter the correct time, it will still "assume" that it was aligned ( but maybe not too well ) and start tracking as soon as you set its Targets to "Astronomical". It is better to do a one or two star align ( even if dummy ), as that will automatically start it tracking.
I suspect its more a drive train / rubber banding error.
Using a 10mm EP is like looking through a straw with a 10" scope, and any slight drift/rubberbanding will allow Mars to drift from the FOV.
An easier test is to use the 32mm EP and "goto" a starfield near Mars, then watch and see if it has a delay before tracking resumes when you use the slew keys. Speeds 2 and above on the Hbx can cause the motors to reverse and hence invoke backlash application, which can be woofy if the drive train nos dont match the real gear slop.

Andrew

[Draco]

Hi Julian

When I saw Alexandar's reply, I presumed he was talking about something I needed to do once-off when I had bought the scope. However when I went through the manual online (which I always try to read when I get something new ;) ) to double check, the "setup" was basically what I was doing before each observation anyways. That is why I said I was doing "everything as expected"

The scope was correctly aligned since when I did a GoTo to Mars, it put mars dead center in the field of view of the main scope :D

Sorry for the confusion and thank you for your reply

[Draco]

Hi Merlin66

I can hear the gears running when it is pointing to an object. Cant remember if it was tracking when I had the 30mm eyepiece in but definitely not tracking when the 10mm eyepiece was used.

RA locks was done. Batteries are ok - I use a jumpstarter and it was fully charged.

[Draco]

Hi Guys

The telescope came back from Bintel. I was told that the firmware was updated and the drive trained.

However I am having the same issue. I did some more tests over the last few nights and came up with some more specific instances when the drift happens

After ensuring the tripod, telescope are level and telescope is pointing North, I Easy Aligned the telescope (using 2 stars, I am using Canopus and Spica).
Using the GOTO I was able to get to Mars (Mars seemed a bit off center so I used the arrows to get it to center and then pressed Enter 3 times to synchronize the new position). I then found that the LX90 tracked Mars for at least 1 hour! The same was for any object that I used the GOTO function to get to.

Now once I had done a GOTO to an object, if I used the arrow keys to even move the smallest of distance, the object started drifting! This was the same even if after alignment, I used the arrow keys to get to an object!

Is this normal? I want to learn star-hopping so that I have a deeper grasp of the night sky. I know a Newtonian is more made for this but having a GOTO as a backup when I cant find what I am looking for is nice.

Am I able to use the arrow keys to get to an object and have it tracked by the LX90 or is tracking only available when the GOTO function is used? BTW with a 10mm eyepiece, Mars went from one end of the field of view to the other and disappeared out in close to 15s.

Thank you

[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

[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.

[Draco]

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]

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]

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 :(

[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 :D )

Andrew

[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.:thumbsup::thanx:

[julianh72]

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


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.


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.


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]

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]

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]

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 :(

[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

[AndrewJ]

Gday Niv


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]

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]

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]

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.