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Old 24-08-2018, 09:28 AM
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Shano592 (Shane)
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LX200 to Laptop - What Do I Need?

Hi All,

To prevent the tearing out of what little hair remains on my head, and to preserve the information for the next time I forget...

I wish to finally set my computer, to be able to autoguide my LX200ACF scope, for a little astrophotography.

I think I have everything I need, and I freely admit that I am yet to try hooking everything up (my laptop is my utility, that is used daily for work). Once I know I have all of the hardware and software, then I can join the two.

Laptop is running Windows 10 Pro (64-bit). 3 hard drives (240GB SSD, 2x 1TB), 16GB RAM.




I have a USB to Serial connector, I think there is a 507 cable with DB9 adaptor in the parts crate.. Easy enough to make, if not there...

I have the GP-USB controller for the autoguider, plus the OAG and LXUSB camera.

ASCOM is installed, along with the LX200 ASCOM Drivers. Stellarium has been installed, as has APT and PHD2. PEMPro is sitting, waiting for everything else to be ok, before installation.

Am I missing anything? What have I overlooked?

Gracias.
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Old 18-09-2018, 08:04 AM
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Shano592 (Shane)
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Bump - Anyone have any insights?
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Old 18-09-2018, 11:13 AM
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redbeard (Damien)
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Quote:
Originally Posted by Shano592 View Post
Bump - Anyone have any insights?
Hi Shano592,

Happy to help but need to know exactly what you are asking.

You have listed a lot of things you have, but not commented on what you have done with them so far. So not sure what parts you need help with.

Have you tested any of the connections, set com ports and got familiar that all the hardware is communicating correctly?

Let us know.


In my setup I do this:
LX200 connected to laptop via serial cable USB to serial adapter. Using Ascom.

Canon DSLR connected to laptop USB. Using BYEOS
QHY5, (connected to guide scope), connected to laptop USB. Using Ascom.

I use Alignmaster software to get good polar alignment and that software uses Ascom to talk to the scope. (Use whatever method you are used to).

Once polar aligned I point the scope to a known star, centre the star, find the star reference, (name), in the handbox and hold down the Enter key for 3 seconds, then press again to sync the star. I do this on 3 stars in different locations in the sky. Once done, using the handbox, tell the scope to slew to one of the previous stars. It will then do a GPS fix and slew somewhere. It never seems to slew to where I have asked it, (probably because I did not have the scope in the HOME position first, but when I did have it in the home position, that has never made a difference for me anyway). But then I use the handbox to correct where the scope should be pointing, so a sync on that star and the goto works very well after that. Not sure if this is the best way, but it always works for me.

I use PHD for guiding.


Cheers,
Damien.
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Old 18-09-2018, 11:59 AM
AndrewJ
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Gday Damien
Quote:
Enter key for 3 seconds, then press again to sync the star. I do this on 3 stars in different locations in the sky. Once done, using the handbox, tell the scope to slew to one of the previous stars. It will then do a GPS fix and slew somewhere. It never seems to slew to where I have asked it, (probably because I did not have the scope in the HOME position first,
That procedure wont work :-)
You need to set your GPS to "At Start", as when it fixes, it overwrites all the internal clocks and resynchs them.
By slewing manually etc before doing a goto ( which triggers a fix if it hasnt been done ) it will get horribly screwed up.
Also, doing synchs doesnt create a model, it just resets the encoder datums, ie last synch over rules all the earlier ones.
If you want to cheat and not do an align
a) Always have the GPS set to "At Start"
b) Put the mount in home position before turning it ON
c) On getting a fix, you are technically aligned
so can then do a slew to a known star and synch.


Andrew
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Old 18-09-2018, 02:30 PM
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Shano592 (Shane)
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Hi Damien,

Thank you for listing your setup. This is what I was chasing.

I have all of the hardware that I believe I need, and needed to know what the software chains are. I think I have everything that you have (or substitutes). Many thanks.

Andrew, yes... as my scope is portable, it has been set for GPS-fix at start.

Thanks to you both for the helps.
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Old 22-09-2018, 01:09 PM
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redbeard (Damien)
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Quote:
Originally Posted by AndrewJ View Post
Gday Damien

That procedure wont work :-)
You need to set your GPS to "At Start", as when it fixes, it overwrites all the internal clocks and resynchs them.
By slewing manually etc before doing a goto ( which triggers a fix if it hasnt been done ) it will get horribly screwed up.
Also, doing synchs doesnt create a model, it just resets the encoder datums, ie last synch over rules all the earlier ones.
If you want to cheat and not do an align
a) Always have the GPS set to "At Start"
b) Put the mount in home position before turning it ON
c) On getting a fix, you are technically aligned
so can then do a slew to a known star and synch.


Andrew
Thanks Andrew, I always knew it was not the best way but it's the way I've been able to get it to work.

I'll take your advice as I've always wanted to know the correct procedure.

I use my LX200GPS on a Milburn wedge all the time so the scope is set to polar mode. I thought the home position in this mode was to point the scope to the SCP, ie fork arms at zero, (in the middle of the stops), and the scope pointing directly out in line with the fork arms, (not horizontal as in Alt/Az). The problem I've had with this is there is not enough room for my camera to clear the fork arms in this position (with finger on the power button just in case).

So is this the best procedure without cheating?:

1. Set 'At Start' for the GPS, (didn't even know that existed but found it in the menu). Or is that for cheating mode only?

2. Next time using scope, put into home position and switch on, (did I get that bit right or is the home position something different to my explanation?

3. Do an auto align, (I'm guessing that because the GPS does a fix here, the scope will point to stars in the sky when slewing to an object rather than slewing to the ground. This always confused me as the biggest issues I've had when using the auto align have been the scope never gets close to the star it mentions and quite often I've had to kill the power to save the camera from hitting the fork arms. Perhaps because I did not have 'At Start' set?

Cheers,
Damien.
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Old 22-09-2018, 02:42 PM
AndrewJ
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Gday Damien
"At Start" is recommended no matter how you align, as it ensures the clocks get synchronised before you do anything.
Letting it wait till IT thinks it needs a fix can cause grief.


As to cheating with a long imaging train,

you can use alignmaster / drifting etc to get it close as you like.
Then turn off and do a clean polar one star align.
When it asks you to put it in home position, simply put it such that the OTA points to HA=0 DEC = 0,

( ie polar home in RA but not in DEC )
When it slews to Sig Oct, let it go.
It will only move about 1deg in DEC and go to whatever RA Sig Oct is at.
When there, just hit enter ( as you are already "mechanically" polar aligned )
It will now slew to the second star, so at this point, undo the DEC clutch and use yr imaging train as a handle to manually guide the OTA so it clears stuff along the way.

Once on target, manually ( not via the slo mo knob ) centre the star in DEC as best you can, then lock the clutch and use the Hbx keys to fine centre it.
Done :-)
The most important thing is to start with the RA in the correct home position, as this affects the hardstop detection.

Andrew







and just manually ensur
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Old 25-09-2018, 12:53 AM
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redbeard (Damien)
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Many thanks Andrew, I understand what your saying.



Quote:
The most important thing is to start with the RA in the correct home position, as this affects the hardstop detection.
With RA, do I have to centre first, (turn RA 2 times left, then back etc and find centre), or does the hardstop detection work it out?

Cheers,
Damien
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Old 25-09-2018, 07:36 AM
AndrewJ
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Gday Damien
There is no "Hardstop detection", as in Meade land, this is done by crashing. The mount "firmware" simply uses dead reckoning from the home position the mount was in when booting ( and reset when starting an align ) to know where it is relative to the stops.

You dont need to spin the base huge amounts.
Based on the hardstop design, there is only one place in the full 680deg RA swing range where you can place the EP over the control panel
( or in this case point the OTA at the meridien )
As such, just carefully move towards that position and if you hit the stop, spin the other way.
If you can position the EP over the control panel, you are at RA home.



Andrew
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Old 02-10-2018, 06:57 PM
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redbeard (Damien)
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Thanks again Andrew,

That makes sense.

On my scope, the mechanism for the RA lock knob seems a bit flaky, as in a grub screw pushing into a threaded rod. I can never keep this tight and are forever having to find a position the grub screw is happy. Do you know if this is normal, or is it just old and worn?

Cheers,
Damien
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Old 02-10-2018, 06:59 PM
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redbeard (Damien)
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Hi Shano592,

Good luck with it all and sing out if you need any other help.

Cheers,
Damien.
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Old 02-10-2018, 09:57 PM
Cimitar (Evan)
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Originally Posted by redbeard View Post
Thanks again Andrew,

That makes sense.

On my scope, the mechanism for the RA lock knob seems a bit flaky, as in a grub screw pushing into a threaded rod. I can never keep this tight and are forever having to find a position the grub screw is happy. Do you know if this is normal, or is it just old and worn?

Cheers,
Damien
My LX200 ACF does the same thing. It's an 8inch and the RA locking knob eventually works its way loose and I have to rotate it slightly, find a clean spot, and then lock it back down again.
I'm also keen to hear whether this is normal or not?
On a related note, I've also been doing the sync thing on 3 different stars. I'll be changing my setup procedure from now on

Cheers, Evan
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Old 03-10-2018, 06:59 AM
AndrewJ
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Gday Evan
Meade has no such thing as a 3 star align with the LX200s.
A 2 star align will create a very simple pointing model
( inAltAz, it is equivalent to faking the lat and long to get a ground to sky conversion )
Doing synchs merely resets an internal encoder offset, ie it affects the entire sky model, so if necessary, on slewing to a new area, goto a bright star and centre then synch. You are good to go for that whole region.
As to the RA knob, its not threaded at the top, its a simple axle with grubscrew at the top.
Have attached piccy of it diassembled.
Maybe find a bolt you can cut down and use that to get a better grip,
or mark the position, then just unscrew the bolt fully and file a small flat onto it in the reqd spot

Andrew
Attached Thumbnails
Click for full-size image (RA Clutch.jpg)
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Old 03-10-2018, 12:36 PM
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redbeard (Damien)
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