Connect a PC to a Meade

[Regulus]

Is it necessary to connect to my LXD75 via the hand controller, or can I plug the Netbook straight into the port on the mount?

And does anyone have a comment to make about Meade's own PC>Mount controlling software?

Trev

[acropolite]

Trevor, If the LXD is anything like the LX, then your PC will plug in via the handbox, the aux port on the mount will be for auto guiding (but may need additional hardware for auto guiding).

You'll need either a coms port on the PC or a USB to com adapter (Aten is a good budget model) plus the Meade connecting cable.

[Barrykgerdes]

Hi

As far as I know the LXD 75 is driven with the 497 controller. However the ETX range is also driven by the 497 controller but the cheaper versions could use the 494 controller that does not have a PC port.

In these versions the PC running Meade programs could be connected to the Aux. port on the mount via a special cable.

Thus it may be possible to connect the computer directly to the mount but you will need that special cable and run the Meade Autostar Suite. However I have never tried to drive a telescope this way without the controller connected to first set up the mount and be available for the necessary calculations.

Barry

[AndrewJ]

Gday Baz

As you note, the 494 type Hbx uses a special "active" cable to communicate via the Aux port, but the Hbx has to also know to communicate that way.
If it is a 497/497EP/Audiostar type Hbx, you MUST use the serial port in the hbx to connect to the PC, as the Hbx doesnt look for the active cable on the Aux Bus.
It is hardwired internally to use the rs232 port in the Hbx for normal comms.

Andrew

[Barrykgerdes]

Hi Andrew
Thanks for the info. I nolonger have a 494 hand box or an ETX type mount to test this out although I do have the cable. I was pretty sure that the 494 handbox needed to be fitted and aligned first but I had not tried it out with the 497 handbox.

I did a fair bit of testing computer control of the ETX with 494 handbox a few years ago when we were patching the Stellarium telescope control program to work with an ETX 70. The main problem was the data transfer was too slow without adding some delays.

However I think the original poster was hoping to do away with the 497 controller altogether and of course this is not possible.

Barry

[Regulus]

Thank you guys.
I have the Audiostar controller.
Andrew, I noted the following in your comment:
"If it is a 497/497EP/Audiostar type Hbx, you MUST use the serial port in the hbx to connect to the PC, as the Hbx doesnt look for the active cable on the Aux Bus. "
Phil: I take it you are talking about an USB>RS adapter with a controlling chip to interpret and change the signals from the USB to make it look like an RS232 port? As opposed to a simple plug adapter.
Barry, your comment "...it may be possible to connect the computer directly to the mount but you will need that special cable and run the Meade Autostar Suite." is worth a follow up and I will email Meade about the possibility, so thanks.
Ideally I had hoped to run the mount with Stellarium direct from the Netbook, though it seems now the hand-controller is necessary and therefore Mead's own PC software is also necessary.

A further Question: Why does the Hand Controller want to know which MEADE telescope is mounted? It seems that, if it is important to it's correct tracking, that knowing the scope dimensions (Aperture/F No. and weight) would be enough instead of picking a scope from a scrolling list of Meade products.

Thx - Trev

[AndrewJ]

Gday Trevor

Correct. For rs232 comms, you will need a std USB to serial adapter.
( Avoid Belkins, try and get one with an FTDI chipset in it )
You plug that into the lappie, then make/buy a std adapter cable
that goes from the USB2Ser to the Hbx. You can make the latter yourself quite easily.

Wont help as they only do telephone support.
( and theres no one left there who knows anything any more )
Some of the specific yahoo groups or the archived Weasner site will give you much more specific info on what you are trying to do.
( and all the other options available )



90% of the brains of the scope is in the hbx, so you will always need the handbox, no matter what drives it.

However, you do not need Meades software on your PC to drive the scope. Many planetariums support native Meade protocols, and if not, you need to load the relevant ASCOM driver, and then just about anything will be able to connect and drive it.

So it knows which way, and at what rate to spin the motors.
Also for hardstops and tripod clash detection values.
The Audiostar supports about 30 different scope types, and it needs to know the mount type and configuration to get those functions right.

Andrew

[Regulus]

Thanks Andrew.
I have been talking to Cathy (Coldknights) about the possibility of using her Bluetooth system but since she doesn't have an LXD mount to trial it on she isn't sure.
However, since the hand controller on the LXD75 and the one on the LX200 are the same (497 Audiostar) I am wondering if it might not be possible to use that (the software in the controller of the two mounts may be different and I will need to establish this first).

But again, thank you it has been useful.
Trev

[coldknights]

Hi Trevor,
The Meade LX200 has the RS232 on the mount.

The LX-75 have there RS232 port in the hand controller
Hope this helps !

[Barrykgerdes]

Hi Trevor

The LX200 and LXD 75 have different controllers. The LX90 and LXD 75 use the "universal" 497 controller that can connect as already explained to a PC that has any PC planetarium program that uses the Meade protocol for communication.

The LX200 (GPS) has the AutostarII hand box controlling the drive computer in the mount. However the external control via the RS232 connector uses the same Meade protocol although there are some extra functions available. As said before the computer control is only available after the telescope has been aligned from its mating controller and this must be still connected.

Barry

[coldknights]

Hi Trevor and Barry ,
Once the alignment is done and you connect to a pc or Tablet using a Serial cable ,Bluetooth or wifi it will show you the position of the scope at the last move or goto or alignment star you did.
Hope this further helps you along !

Oh as Barry said the hand controller must be left connected to the mount as the serial cable ,Bluetooth or WIFI connects to the RS232 at the bottom of the hand controller for your model.

[AndrewJ]

Gday Cathy



Just a note here.
If you have a 497/Audiostar controller and are polar aligned, the Alt and Az reported via serial commands lies :D. The reported RA/DEC is correct, but the reported Alt and Az is utter crud. The Alt/Az shown on the hbx is correct, but the rs232 returns are just wrong.



For the 497/Audiostars, yes, but the LX200 GPS/LX600/RCX/LX850 can all be run without a handbox if required.
Also, the 497s can actually be run quite happily via a remote handbox if the scope has not been aligned. ie you can actually do a full remote unpark or align if required, but you do need the hbx connected to the scope.

Andrew

[coldknights]

Hi Andrew thanks for the clarity on the Meade mounts !
I think Trevor may have the information needed now to decide which way he has to connect his mount to a pc and remote control it with software .

[Barrykgerdes]

Hi Andrew
I have never noticed the readings in the Alt/az being in error but I could imagine this being the case if you send the alt/azm request from an external controller when the mount is actually polar aligned. I expect it is just returning the actual encoder readings not converted for the mount attitude. The controller programs I wrote don't send these commands as I get the Alt/azm by the standard conversion calculations from the RA/Dec that is being done in the controller.

I have a 497 controller and I think I have a working DC mount somewhere. I will try to make a test rig to check on all the controls

I don't have any way to test the Autostar II any more but I still have a working LX200 classic test rig and this needs to go through an alignment procedure before you can get remote access. This defies something I was able to do with my LX200 18 years ago when I trashed the hand box serial connection buffers so that the hand box would not work. I was still able to do an alignment from a remote PC with a program I wrote. I have since tried to duplicate the conditions without success.

Barry

[AndrewJ]

Gday Baz



Correct ( almost )
The raw encoders are converted to normalised "base relative" values.
To report the Alt/Az when polar, these need to be transformed.
When viewing via the hbx, this conversion is done properly
but via rs232, the raw base relative coords are sent instead.
Ie down here, in polar, a 497 will report Alt as -ve (DEC) :shrug:

Andrew

[Regulus]

Thanks Cathy, Barry and Andrew, I think I have enough to be going on with.
My controller is the Audiostar but no indication of it being a II model.
So I see that:
The hand controller stays connected to the mount and the PC connects to the hand controller via a RS232 cable (USB>RS232 converter as necessary), WiFi,
Or via Cathy's Bluetooth system.
At which point the use of a range of software becomes possible.
Really appreciate the Answers.
Trevor

[AndrewJ]

Gday Trevor



The II model referenced is for the AutostarII hbx which is used with the LX200/RCX/LX600/LX850s. It is a dumb terminal and very different to the 497/Audiostars.
( There are actually 2 versions of Audiostar as well, but for end users, the difference is invisible )

Now one last thing, what firmware have you got loaded???
The basic Audiostars had lots of bugs included for your convenience, and the latest versions of the firmware ( that were written to include the LX80s ) stuffed up a whole lot of other stuff.
If you are going to be using a lot of serial control and guiding etc with an LXD75, i recommend loading patched A1F7 firmware only.
Thats the most stable version there is for the older models.

Andrew

[Regulus]

Thanks for that Andrew