Connecting an LX200 to a USB port on my laptop?

[Moontanner]

Hello,

I'm looking to connect a laptop to my LX200 and was wondering if there's anything special about the Meade cables? Is it possible to simply get an RJ11 to USB 2.0 adapter?

I have looked at the Meade offerings and can't say that I'm overly impressed with the mess of adapters or the ridiculous price tag.

Any advice will be greatly appreciated.

Regards.
Ross.

[AndrewJ]

Gday Ross
The Meade scopes use std rs232 so any USB2Ser adapter can be used.
That said, several chip brands ( Belkin is notorius ) dont play quite so well with Meades as they dont appear to fully comply with the rs232 specs at times, esp when the scope is in download mode.
FTDI based converters seem to work well.
After that, all you need is a correctly wired RJ11 6P/4C plug and a DB9 connector ( unless you want to hard wire to the USB2Ser yourself )
Only 3 wires are used, but you do need to use the correct 3 wires, as lots of different models use different pins in the RJ11.
Is it an LX200 Classic or an LX200GPS/R/ACF ????
There are lots of wiring diags on the LX200 forums to cover how to make the cable.

Andrew

[Moontanner]

Hi Andrew,

It's an LX200GPS.

I did manage to find a few wiring diagrams, but it's always a challenge trying to figure out which information is relevant to my situation.

Thanks.
Ross.

[AndrewJ]

Gday Ross

If its an LX200GPS, then its pretty simple
Here is an isometric view i made up for the cable
if you are comfortable making cables.
You will find this and several other versions in the files section
of the Yahoo group LX200GPS

Andrew

[Moontanner]

G'day Andrew,

I'm definitely up for making the cable myself and that diagram helps explain things well enough for a trip to Jaycar. If I'm lucky I might even have the parts in a storage tub somewhere.
I'll head on over to the LX200gps Yahoo pages for a squiz now.
Thanks for the helpful advice.

While I'm picking your brain, do you have any recommendations for software that will work well with a 10" LX200GPS? I've decked out my accessories cases with a webcam, a DSLR with various attachments and enough eyepieces for reasonable visual work. Some decent software to compliment various arrangements would be another welcome addition to my kit.

Regards.
Ross.

[AndrewJ]

Gday Ross


To do what????
For firmware loading and patch application, i only recommend StarPatch.
http://www.stargps.ca/downloads.htm
For digging into whats in your scope ( more diagnostic based ), i have written a PEC editor. ( The beta version is best at present )
http://members.optusnet.com.au/johansea/
It also does lots more things if you have patched firmware, as we can then peek lots of stuff as reqd.
For planetarium type stuff, Stellarium or CartesduCiel are good freeware.
For Guiding and drive analysing, PHD, PHD2 or Metaguide are all good freeware apps.
All work well with std webcams.
Metaguide also has a video mode in it and can work at much higher framerates when required.
For PEC training, PEMPro is the best, but it is a paid for app.
If you train using normal guiding, you will need to invert your data ( one of the reasons i first wrote my app ), as there is a sth hemi bug in the code.

Andrew

[Moontanner]

Hi Andrew,

I was thinking more of the planetarium type stuff that you mention. Personally, I don't mind paying for something that is good and has a reasonable amount of support once purchased.
As usual, your response has unearthed a whole new set of things to look into. I'm pretty sure I'd like to go further with the scope once I get my head around the equipment side of things. The way the scope works at the moment I'm already sure that the goto system needs some attention.

Thanks.
Ross.

[AndrewJ]

Gday Ross

How are you mounted???
If AltAz, the gotos shld be pretty much spot on, as long as you have trained the drives correctly first, and choose suitable align stars.
In Polar, there are known bugs in the 2 star align process. I have tried to fix them in the patches, but not sure it is fixed properly yet.
If Polar, you really need to get a good mechanical polar alignment, then just use a std polar one star align.
Goto accuracy will then be pretty much relative to yr polar align accuracy.

Andrew

[Moontanner]

Hi Andrew,
I'm just alt-az for now with a possible polar alignment setup in the near future. At this stage it seems to me that the drives are out of whack and in need of training.
I also own an ETX105 and it has no trouble tracking an object over an hour or so. The LX200gps has a noticeable error when tracking that I'd love to get on top of.

So much reading to do.
Cheers.
Ross.

PS. Stellarium is a b it of fun without a connection to the scope.

[AndrewJ]

Gday Ross
The LX200 should be far better in AltAz than the ETX if everything is OK.
Drive training is moderately critical for aligning, but also star selection can have a big effect, esp if you use stars too low down.
Orthogonality is also a possible part of the mix, but only for gotos, not tracking.
What stars are you using to do yr aligns???
Early evening, using Achernar and Rigel Kent should always result in a good align.

Andrew

[Moontanner]

Hi Andrew,

You might be onto something with my method of star selection as I've totally botched the alignment several times now. I've definitely found the scope easier to align at a darker site where "the brightest star" has been fairly obvious. The last two times I used the scope at a dark site I was able to track Jupiter well into the morning hours with only minor manual adjustments.
Alas, most of the time I'm trying to sneak in some viewing time in less than ideal locations and my knowledge of the stars is limited. I usually just let the scope do it's thing and try to keep up.

I have noticed that my ETX has a few features that help with the alignment process. Most notably the RDF and the controller telling me which star it's trying to align with.
I'm about to order a RDF and illuminated reticle eyepiece for the LX200 which should help somewhat. I guess I need to read the manual again and start familiarising myself with the common alignment stars.

Thanks for the advice.
Ross.

[AndrewJ]

Gday Ross
There is a handbox option to tell the scope to use the real star name vs simply use "brightest".
If you are auto aligning, you also need to do a Calibrate sensors ( after you have done drive training ). The cal sensors will recalibrate the North and level sensors for your local situations, and thus make finding the first align star easier ( as it will get much closer )
To Cal sensors, you need to find Sig Oct, which can be a pain.
Sneaky method is
a) Do a std manual 2 star align, and ensure Gotos are correct.
b) Select and "Goto" Sig Oct, and centre it
c) Mark/note the setting circles.
d) Do the Cal sensors routine
e) When asked to centre Sig Oct, slew manually to the premarked setting circle positions. Sig Oct shld be near the centre of the 8x50 finder
Centre it and you are done.
Auto aligns should now be much more accurate on the first star.

Andrew