Autoguiding a Losmandy G11

[Which Star is that]

Hi everyone,

I have a Losmandy G11 (not Gemini) and would like to set it up with an autoguiding system. I have never done any autoguiding before, but read many of the posts about it and read many adverts for kit that seem to range enormously in price!

The instructions for the Losmandy state that the CCD port will work with "all SBIG Auto Guiders", and I see many references to ST-4 autoguiders. Is that the same thing? If so what do I plug in and where?

I have a Celestron Neximage which works on my Windows 7 laptop and which I think can be used to autoguide. While I understand it's limitations re not picking up even moderately bright stars, I hope to get round that by using a resonably large guidescope.

I guess I would use something like PHD software, but how do I connect PHD software to the losmandy? Do I need some kind of adaptor to connect the telephone type cable from the Losmandy to a USB port on the PC?

Perhaps someone knows of a (simple!) explanation to the mysteries of ASCOM, GPUSB, GPINT, Pierro Astro, GCUSB, ST-4, and how they connect and what is compatible as I have trolled round the 'net and cannot find a good explanation of how it all goes together

[wouterdhoye]

Hi,

The Losmandy G11 uses the ST4 pin layout for the guider port. Though when connecting a guider you have to make sure the guiding camera uses potential free contacts. or in other words there can be no voltage on the output of the autoguider. Essentially the autoguider input of the losmandy is a direct replacement of the buttons of the hand control. So you actually need to be sure that the output of the autoguider uses simple contacts and puts no "foreign" voltages on the G11 electronics as this may damage them. Normally true ST4 output should be compatible. Some camera's may require a relay box (like for instance the SBIG ST7 and up or SBIG STL cameras ) .

I hope this somewhat explains what you have to watch out for. maybe if you can tell what guider you are looking in to you can get more direct assistance.

Kind regards,

Wouter.

[Which Star is that]

Thanks Wouter. That's great info! Sorry I haven't replied earlier, but I did't get an email telling me there was a reply and I'm a bit of a newbie here! Sounds like you know a bit about the Losmandy and auto guiding.

Am I right in thinking that to use my Celestron Neximage (which apparently is basically a Philips SPC900 webcam) I would have to connect it to a PC and guide using the PHD software? If that is right how do I connect the PC to the G11? I have an adaptor which I got to supposedly control an ETX via a PC which appears to convert the telephone type plug to a serial port, but I have never used it as my PC's do not have serial ports! If I got a USB to serial converter would that work or does anyone make a USB lead direct to the guide port on the G11.

If I knew how I'd add a photo of my adaptor with this post, but I don't know how to do that yet! But basically it has a serial port on one end and a phone type socket on the other. The phone end seems to only have 3 pins with connectors out of the four I would expect on a 'normal' telephone cable. Is that right for ST-4 do you know?

[Freddie]

One option is neximage into the laptop, run PHD and then one of these (other manufacturers are available) to link the output of PHD from the laptop to ST4 port on the mount.

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Imagers-Shoestring.asp?p=0_10_5_0_5_10

[Gina]

They call it "low cost" - I don't think so! There's plenty of cheaper options, including an EQDIR box on FLO.

[Which Star is that]

This seems to be my problem! There seems to be many ways to skin this cat! The EQDIR is certainly cheap, but I don't know if it (or is it an EQMOD I need!) can be made to work with my G11! I have joined the Yahoo group to see if anyone knows if it will. The trouble is I don't really understand half the terms they refer to!

The Shoestring Astro GPUSB from OpticStar does at least seem to have the correct combination of connectors - a USB end for the PC and an RJ-12 which would go in the Losmandy G11 conrtol box, so even if it is a bit pricy it looks like it should work... In fact having just scrolled down through the long explanation it actually lists the G11 as compatible :grin:

Any cheaper (and known to be compatible!) suggestions much appreciated...

[wouterdhoye]

Hi,

the GP-USB relay bos is exactly what you need. And truth be told I don't think it's really expensive. (ruining your G11 electronics with something that didn't work as it should is a lot more expensive)

Kind regards,

Wouter.

[Which Star is that]

Yes, looks like GPUSB relay is the simplest way for me. £80 is not cheap, but not the end of the world to get something that is known to work and keeps it simple. I will keep an eye on the EQMOD project, but at the moment it doesn't seem to be compatible with the Losmandy and the part is not in stock anyway, and no indication of when it will be available.

Thanks for all the advice.

[Which Star is that]

Just seen it is available direct from the maker in the US for $75 and since I travel a lot to the US I can get it delivered over there, so looks like I can get it at a bargain price! :grin:

Why is it £80 in the UK - usual rip off!