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  #1  
Old 03-07-2018, 09:04 PM
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ninja2 (Chris)
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"Training" the Meade ETX-90

I had some problems with my ETX-90 during alignment. With the help of my local vendor we concluded the handbox was misdirecting the scope during alignment. So he reloaded the handbox software and now it's behaving much better.

However the GoTo accuracy still seems not very good. So I was reading up on "training" the ETX-90 at Weasners site (impressive but *very detailed*):
http://www.weasner.com/etx/techtips/etx_tuneup3.html

It explains how to use Polaris if training for Alt_Az mode usage, or to train for Polar/Equatorial mode using a terrestrial target,

Curiously the Meade Intruction Manual only explains training using a terrestrial target, and makes no mention of training using Polaris (or the South Celestial Pole)

At this stage I'm happy to use either mode, but I have a couple of questions:

1) What target can I use for Alt_Az training when I need to point to the South Celestial Pole. I know how to find SCP ... but AFAIK there's no easily visible star close to SCP (I'm in suburban Adelaide)

2) if I train using a terrestrial target can I only expect it to work in Polar mode, or can I also to use Alt_Az mode successfully?

thanks in advance ...
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  #2  
Old 04-07-2018, 11:48 AM
AndrewJ
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Gday Chris


You should ALWAYS do drive training using AltAz mode and a terrestrial target. You should also try to use a target where the OTA is as close to perpendicular to the RA/Az axis as you can get.
All drive training does is measure the backlash in the geartrain so that when the direction reverses, it can account for it.
That said, what firmware version doyou have loaded?????



Andrew
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  #3  
Old 04-07-2018, 09:04 PM
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G'day Andrew

Setup > Statistics tells me version A3S5 ...

By concidence you're the second person today to explain the purpose behind training (i.e. backlash compensation) and that really helps understanding (thanks!).

Does it matter how tall the training target is. How about a mobile phone tower, and to get the elevation I set the telescope up say, 10 metres from the tower base, is that good choice? Should I move even closer, or maybe look for something much higher, a mountain side / cliff maybe ?
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  #4  
Old 05-07-2018, 07:57 AM
AndrewJ
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Gday Chris
I dont know A3S5 well but dont really recommend it for LX90s.
As to training targets, its not height you need, its distance.
If you set up AltAz, set the tripod flat and level, then pick a target as far away as you can on the horizon.
If you are on a wedge, again, pick a target on the horizon and keep the OTA reasonably close to DEC = 0.
Andrew
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  #5  
Old 05-07-2018, 03:29 PM
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Quote:
Originally Posted by AndrewJ View Post
I dont know A3S5 well but dont really recommend it for LX90s.
Huh? I assume A3S5 is latest. Why don't you recommend it? i.e. what do you recommend for an ETX-90?

Quote:
Originally Posted by AndrewJ View Post
As to training targets, its not height you need, its distance.
OK, I now realise I misinterpreted 'perpendicular' in your previous pointer:

Quote:
Originally Posted by AndrewJ View Post
You should also try to use a target where the OTA is as close to perpendicular to the RA/Az axis as you can get.
I understand now... tks again
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  #6  
Old 06-07-2018, 07:10 AM
AndrewJ
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Gday Chris
Quote:
Huh? I assume A3S5 is latest.
No its not
A4S1 is the latest, and its orrible as well ( I suspect you may have had that loaded, as its caught a few people now )

Quote:
Why don't you recommend it?
Its full of bugs, and also, in an attempt to get LX80s working, Meade have been reworking how motor speed calculations get done, PEC has been neutered to be almost useless and new bugs have been introduced.
As such, i gave up trying to patch the later firmwares as ( IMHO ) there was no benefit.
Quote:
what do you recommend for an ETX-90?
What type????
ie is it an older classic or one of the new units with the plugs in the fork arms???
The new ETX-90s use a different drive system to the older ones and as such need to be selected with correct ratios in order to work.
Recent firmwares cocked this up and select the new units using the old ratios, and as such, they wont point properly.
Need to know more about what you have, but i would probably suggest using patched A1F7 firmware, and selecting your mount as an ETX-80.


Andrew
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  #7  
Old 06-07-2018, 12:36 PM
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Well well well, the plot thickens!

Quote:
Originally Posted by AndrewJ View Post
A4S1 is the latest, and its orrible as well ( I suspect you may have had that loaded, as its caught a few people now )

Its full of bugs, and also, in an attempt to get LX80s working, Meade have been reworking how motor speed calculations get done, PEC has been neutered to be almost useless and new bugs have been introduced.
As such, i gave up trying to patch the later firmwares as ( IMHO ) there was no benefit.

The new ETX-90s use a different drive system to the older ones and as such need to be selected with correct ratios in order to work.
Recent firmwares cocked this up and select the new units using the old ratios, and as such, they wont point properly.
That's all more than a bit concerning! Is this sad state widely acknowedged by the Meade user community?

Quote:
Originally Posted by AndrewJ View Post
... is it an older classic or one of the new units with the plugs in the fork arms???
Mine's brand new, the handbox plugs into the fork arms

Quote:
Originally Posted by AndrewJ View Post
... i would probably suggest using patched A1F7 firmware, and selecting your mount as an ETX-80
Where do I find all these different firmware variants?

mucho thanks
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  #8  
Old 06-07-2018, 02:46 PM
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Gday Chris
Quote:
Is this sad state widely acknowedged by the Meade user community?
Yep. Its one of the reasons we resorted to writing patches.
Lots of threads out there on this now on the yahoo and Cloudy nights sites. Weasner closed down his site before a lot of this came out, so you wont find much re it on his archives.

Quote:
Mine's brand new, the handbox plugs into the fork arms
OK, then i am guessing that your original handbox had A4S1 on it, and in this case, it would not have worked with your mount if you selected ETX-90 for the model. If you had selected ETX-80, it would have worked.
A3S5 will correctl select the new ETX-90s but i stil dont like its bugginess.
ref https://www.cloudynights.com/topic/5...x-90-problems/


Quote:
Where do I find all these different firmware variants?
As per above, there are lots of threads on the CN and Yahoo sites dedicated to Meades re this, so i suggest you read a few before jumping. The patches, firmwares and 3rd party loader are all on the StarPatch site http://www.stargps.ca/downloads.htm
but as per above, i suggest reading some other sites first before doing anything.
Also, Meades ASU will not properly update user data or load satellites, asteroids, tours etc to your handbox either, as Meade broke the code when they switched to the new processor in the Audiostar Hbx.

You will need to use my PEC editor to do that ( if you want to ).
Andrew
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  #9  
Old 06-07-2018, 09:28 PM
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Thanks Andrew, I'll go do some reading !

Possibly related question: So when I compared particular RA/Dec numbers on the Audiostar screen with those for same object/same time on SkySafari app on my android, and Starry Night Pro on my PC, I noticed the Audiostar numbers were always a bit different to SkySafari & Starry Night, whilst the latter two were always in very close agreement.

When I say a bit different , from memory it was like/around 2 seconds (Dec) but I may I need to revisit and check if it's important.

Wondering if this is a scope error, or me?

Perhaps it's a known issue too, related to the firmware saga?

By the way - the vendor only reloaded handbox firmware, so it's still the same new handbox hardware, as purchased.


Lastly ... Is this an ETX-90 problem only, or does it apply to other Meade scope firmware?


cheers

Last edited by ninja2; 06-07-2018 at 10:27 PM.
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  #10  
Old 07-07-2018, 07:02 AM
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Gday Chris
Quote:
So when I compared particular RA/Dec numbers on the Audiostar screen
The Audiostar uses cut down equations of motion to calculate the positions of many things. It also doesnt do precession calculations, and as such what it reports will differ from a fully up to date phone/pc app that can use all the latest data and calculations.
Quote:
the vendor only reloaded handbox firmware, so it's still the same new handbox hardware, as purchased.
Understood, there is nothing you can do re the hardware.
That said, there are big differences between some of the firmwares.
Quote:
Lastly ... Is this an ETX-90 problem only,
For not being able to select an ETX-90 correctly, yes, it only applies to the new units with the plugs in the fork.
As per the other thread, ( and as suggested by Meade ),selecting an ETX-80 will get the correct ratios so it points correctly, but thats just a cop out by Meade. They should have fixed it by now.
Andrew
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  #11  
Old 07-07-2018, 08:05 PM
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Quote:
Originally Posted by AndrewJ View Post
The Audiostar uses cut down equations of motion to calculate the positions of many things.
Doesn't that mean I [often] won't find a target? Those errors are too big IMO, so this could be a side effect of the firmware issue.

After reading up I'm now of two minds: Do I accept the firmware situation, do the fiddling and keep the scope, or do I return it? One reason I chose Meade is there long experience in the business and their reputation. I expected the ETX-90, havng been around quite a few years, would be a fully sorted and stable product. Wrong!

A troubling concern is I could load new firmware but come up against a bug further down the track that misleads or fools me. After all the main reason for this scope is to learn and enjoy. Fiddling with firmware on a brand new product is not enjoyment!

I assume you own an EXT90 Andrew? What firmware are you using? Do you have a list of those known "bugs" ?

cheers
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  #12  
Old 08-07-2018, 08:29 AM
AndrewJ
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Gday Chris
Quote:
Doesn't that mean I [often] won't find a target?
If you get a good align, pretty much all targets should be in the FOV of a 26mm EP. Planets can vary a bit, but would normally be in the EP.
The selection of align stars and accuracy of centring them can have a big effect on accuracy.
One trick if you dont have a Xhair EP is to defocus quite a lot before aligning. The stars will look like big donuts, and it is much easier to centre this than a perfectly focussed star.
Quote:
A troubling concern is I could load new firmware but come up against a bug further down the track that misleads or fools me.
I basically stopped at A1F7 and this works pretty well, and a lot of the bugs have been patched out. Its been tested in the field for several years now, but if you load it, you will still need to select an ETX80 in order to get the right ratios.
Quote:
I assume you own an EXT90 Andrew?
Nope. ETX-125, LS-6" and LX200GPS 10"

Quote:
What firmware are you using?
Depends :-)
I have 2 x 497, 2 x 497EP and 2 x Audiostars.
I never really know what firmware i have loaded as it depends on what i am doing, but for stable work, i load A1F7 with the patches onto the Audiostars.



Quote:
Do you have a list of those known "bugs" ?
I have dozens of lists, as each firmware fixes some and removes others.
If you read the A1F7 patch file via StarPatch, it is broken into "bugfix" and "enhancement" sections. Just read the bugfix bits to see the major ones.

Andrew


PS To be fair, pretty much all mounts in this price class have some sort of bugs etc.

For normal grab and go viewing, they work well for their price, as long as you get the alignment done accurately.
I know of the Meade bugs in detail because i have been working with them for years, but other mounts arent 100% problem free.

Last edited by AndrewJ; 08-07-2018 at 09:25 AM. Reason: added a ps
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  #13  
Old 09-07-2018, 09:22 AM
alval (Alan)
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Hi Chris,
Iíve got an etx observer similar to yours but the larger 125 with the same firmware. Iíve had it over a year now and had issues to start as well. Mostly it was set up which does affect go to.
Iíve found the base has to be level use a small level across the base behind the forks not the bubble level. ( as useful as a hole in the bottom of a bucket)..
The compass is affected by metal, the small thumbscrew in the eyetube holder may affect it, remove it to see if the needle moves.
Make sure you have your site as your location accurately by gps and that the timezone is +930. Half an hour out is about 7 degrees as i found.
Enter accurate time at start up, ive got atomic clock app on my phone (free)
Yes train drives as others have said on a distant light pole or stobie they have horizontal and vertical aspects on them to move back to when aligning.
You can also train motors if you change power source or put in new batteries.
Everything adds up and it doesnt have to be out by much to miss targets.
Once working the views are great. Now if only these clouds would nick off!
Hope this helps
Al
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  #14  
Old 09-07-2018, 05:21 PM
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I used to own an ETX 105.
I found that after re-calibrating the Compass to true north the Scope performed well.
To do that I had to remove the Battery and trained it to Sigma Oct.
Regards J.
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  #15  
Old 10-07-2018, 02:58 PM
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ninja2 (Chris)
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Thanks everyone for all the excellent info and suggestions. I'm distracted by one of my other hobby projects at the mo', but will soon be back onto the scope "project" to sort out my firmware following AndrewJ's inputs, then do training etc.

Using a spirit level sounds sensible too. I reckon that would be done along the horizontal direction between the forks (i.e. E-W when OTA facing N)

I'm sure I'll have more questions so not doubt soon i'll be back here with more queries .... knowledge is power!
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  #16  
Old 11-07-2018, 04:33 PM
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I just tried to connect my ETX-90 to my PC but Audiostar will not connect.

I don't have an RS232 port on my PC so I purchased the Meade 07507 USB-Serial cable, but later saw on this Meade web page that it is the earlier version (with the mid-cable lump) that will not work with Win10. So I put it aside and purchased a plain old USB-RS232 cable from local MSY Technology store.

When I connect the Audiostar handbox to the PC a new port appears in Device Manager > Ports as "Prolific USB-to-Serial Port (COM3)" although it has the dreaded yellow exclamation mark. I've installed the Prolific driver downloaded from Meade. I 've installed Autostar Suite and told it to use COM3.

But when I choose Telescope > Protocal > Autostar via Serial Port (F6) I an error box pops up with "Can't open COM3 : GetLastError returned 2".

As mentioned I'm using the Meade #505 cable set, but not the newer version of the Meade 07507 cable. I see one for sale on eBay but it's from USA and will take a few weeks.

Any suggestions appreciated! In particular do I need to fork out for the newer Meade cable, or should a common USB-RS232 cable do? If yes, is there an Australian supplier of these (my Google Search showed none)?

thanks
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  #17  
Old 11-07-2018, 05:32 PM
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Hi Chris,

Uninstall the driver you downloaded from Meade and use the driver that came with your USB to RS232 cable.

You don't need the Meade USB to RS232 adapter as I'm guessing that it's just an expensive version plus postage of the one you bought from MSY.

Cheers,
Damien.
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  #18  
Old 11-07-2018, 05:37 PM
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Gday Chris
Any USB2rs232 converter will work for connecting, as long as you have a correctly wired 505 cable set, and the converters drivers work.

Quote:
I've installed the Prolific driver downloaded from Meade.
Many people have reported problems with Prolific based converters and W10. Using old drivers fixes this in many cases.
Prolific actually have a chip checking utility on their website that will confirm if the chipset you have will work with W10.

FTDI based usb2ser converters seem to be more robust than most
but using older prolific drivers may make your current unit work.
Lots of threads on this problem exist on the Meade scope based websites.
Its just a result of USB2Ser converter manufacturers not obeying the rules, as there are many counterfeit chips out there.



Andrew
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  #19  
Old 12-07-2018, 01:57 PM
alval (Alan)
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Hi Chris and AndrewJ

This discussion about reverting to older versions of more stable software for the newer etx has me thinking. I have an etx 125 observer A3S5 firmware.
I have recently opened up the etx, (as you do when youíre bored and I took pictures). The drives seem substantionally bigger than the older models from what i can tell so the gear ratios probably have changed. Would you need to change the alt/ratios in the telescope model settings to the current ones in the newer firmware manually to track correctly? as the older firmware wouldnít have taken this change into account.

Alan

Sorry if i posted twice issues with fat fingers and ipads.
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  #20  
Old 12-07-2018, 04:23 PM
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Gday Alan
Quote:
The drives seem substantionally bigger than the older models from what i can tell
Not true without piccies :-)


Quote:
so the gear ratios probably have changed.
Not that i can tell from the firmware.
The lates ETX-90 ratios have changed back to the very earliest values, but the 125 has only had one value across all firmwares.
Quote:
Would you need to change the alt/ratios in the telescope model settings to the current ones in the newer firmware manually to track correctly?
Dunno.

I havent heard any problems re the 125s ( and i get sent lots of bug reports privately ).
If it aligns and tracks, then its OK.
The new ETX-90s running on the wrong ratios simply did not work.
If its wrong, it is very evident.
Andrew
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