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ATTENTION ALL LX600 OWNERS

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#1 moxxyman

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Posted 11 March 2014 - 09:54 AM

I was concerned about the 7 second delay when reversing declination in guide rate. After a lot of head scratching, I came to the conclusion the Anti-Backlash does not work when in guide rate. If you rest your finger on the slow motion control and apply a reverse in dec direction, you should feel the snatch as the backlash slack is taken up. There is no take up. It works fine in speed two. I consulted someone far more knowledgeable than I in the nature of firmware programming. He has taken a look at the code and has come to the same conclusion. Dec reversing does NOT apply any anti-backlash when in Guide rate. This affects every LX600 which has been released or is about to be released. If you are lucky enough to have no slack in your dec gear train, this wont affect you at all (for now). Unfortunately, I suspect almost all DEC gear trains will have a fairly significant amount of slack in the gear train. Anti-Backlash is supposed to deal with this problem (that's why it's there). Sadly, it does not apply any anti-backlash at all.  This means pretty much all of us. Dec guiding with Starlock is hopeless and will never work if it has to deal with such an enormous amount of slack in the gear train. Do your own tests. How many seconds does it take for DEC to reverse in guide rate?? Try putting your finger lightly on the DEC slow motion knob and reverse the DEC direction. You should feel a judder as the gear train rotates in fast speed to take up the gear slack. Try it in speed two and you will feel this in operation. We desperately need to make Meade aware of this so they can work on a firmware update.

Until a fix is made, I suggest you switch off Starlock and use a good polar alignment instead.



#2 MistrBadgr

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Posted 11 March 2014 - 04:08 PM

That is good information.  Did you call Meade Customer Support and tell them this?  Let me know if you did not and I will.

 

Bill Steen


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

#3 tlwarnke

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Posted 11 March 2014 - 04:51 PM

You can read the full dialog between Wayne and Andrew Jahansen in the LX600 yahoo groups.
Thanks for doing this. I will check my LX600 out if it ever warms up.

Terry

#4 moxxyman

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Posted 12 March 2014 - 12:04 AM

Notifying Meade for you involves a number in the USA. As a UK dweller, Meade point me towards my telescope supplier in the UK if I have any problems. So far, my supplier  "Telescope House" has not responded to my email on this problem. They are usually very helpful, so I expect they will soon. They will need time to make their own tests to confirm what I am saying is true. Meanwhile, by all means test the backlash yourselves, on your own scopes. Andrew is finding out more and more on the nature of the problem as time passes.  So, for now, I would use starlock only to put you in the ballpark for your goto's. Dec guiding will not work. Switch Starlock off and rely on your alignment.



#5 moxxyman

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Posted 12 March 2014 - 01:14 AM

OK....Andrew has been busy. If you set RA Guiderate (not backlash) to anything other than 66%, DEC Anti-Backlash compensation in guide speed will suddenly work. This is all down to Andrews work, so send any gratuitous beers to him. Andrew will most likely provide the technical details as to why changing the RA Guiderate suddenly allows anti-backlash in DEC to work (in guide speed), but I suspect it is just dodgy code. Meade should hire Andrew to write there firmware.

SOOOOOooooo if you want to see the difference, Set RA GUIDERATE to say 67 and set guide Speed (speed 1 on your handbox) and try a DEC reversal. You will then see how it is supposed to work. You can even here the backlash being taken up in speed 1. Put your finger on the DEC slow motion knob and try it. Did you feel it make an initial snatch?? this is the backlash compensation taking up the slack in your DEC gear train. This is how it is supposed to work.



#6 moxxyman

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Posted 12 March 2014 - 01:47 AM

SOOOOOooooo, Now Andrew has done all the fault finding work, and made life easier for Meade programmers, Now they know which bit to look at, they may as well alter the slew rate for train drives while they are at it which is way too fast.



#7 moxxyman

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Posted 13 March 2014 - 10:51 AM

My telescope supplier has forwarded the information to Meade USA. Hopefully they will acknowledge the problem and release a firmware update soon.



#8 MistrBadgr

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Posted 14 March 2014 - 07:36 AM

I also sent in some information to someone I know who forwarded it on.  They will get it from two different directions.

 

Bill


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

#9 moxxyman

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Posted 14 March 2014 - 10:03 AM

Thanks Bill.

The more of us that confirm the problem with their own scopes (which will be all of us) the better.



#10 moxxyman

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Posted 17 March 2014 - 02:53 PM

If others can confirm this problem with their own LX600's and post on this thread, it might hasten Meade to work on a firmware fix to sort this problem out. I have no doubt all LX600 owners are affected, so it is up to us as customers to confirm this issue. It does not mean your telescope is unusable. Outside of this problem it really is a great piece of kit. So, if you could set RA guide rate to 66 and prove to yourselves the failure of DEC backlash compensation in guide speed to operate, it helps not just ourselves, but every prospective owner of the LX600 model. Please add your own weight to this cause.

 

Moxxy



#11 cgordo5

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Posted 18 March 2014 - 11:14 AM

Hi,

 

I wasn't able to duplicate the issue on my LX600.   I tried it with RA guide rates of 66%, 67%, and 10%.   Maybe my telescope has a lot less DEC backlash than yours.  My anti-backlash settings are 025% for DEC and 005% for RA.

 

Charles







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