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Losmandy Gemini guiding question

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#1 Freddy WILLEMS

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Posted 20 April 2009 - 01:15 AM

I do not have a CCD or so, but I want to use the Losmandy/Gemini guided.
So I have a Laptop /USB port and a regular webcam and PHD guiding, which works great.
Now I use the regular RS 232 port of the Gemini box to connect to the computer and the webcam is USB connected with another port to the computer.
I still have some drift when I point North.
I'm using an Orion 80ED and a DFK camera on a Meade 10" and 5 minutes shows some trailing, is the Orion 80ED f/7.5 not good for guiding ?
Or do I need to use the specific guiding port on the Gemini ? I thought this was only for specific CCD use ?

Freddy

#2 lowdog

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Posted 20 April 2009 - 03:16 AM

I use a Orion SSAG with PHD and go directly into the autoguide port on the Gemini box and a USB cable going directly to the USB port of the laptop. Also check to see what mode you are in. The autoguider port is only active when you are in photographic or all speeds mode.

Jeff

#3 Freddy WILLEMS

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Posted 20 April 2009 - 04:29 AM

wow, I never used or knew that Jeff, Thanks.
What cable do you use for that, I mean the connector that goes into the guiderport of the Gemini box ? Is it the same as the RS232 ? I guess not.
Freddy

#4 Charlie Hein

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Posted 20 April 2009 - 08:17 AM

Freddy, how "new" is the Gemini? Specifically, do the cables that go to the RA and DEC motors have round "DIN" type connectors, or are they RJ45 "modular telephone" type connectors?

Here is why I ask... you'll need an adapter from USB to the "ST-4 compatible" guiding interface on the Gemini controller. I'd recommend having a look at the Shoestring Astronomy web page for the pieces you need. If you are using the NEW style Gemini box (the NEW style has a circular DIN connector to connect to the motors), then you will need the part "GPUSB". If you are using the OLD style Gemini box (the OLD style has a modular RJ-45 connector to connect to the motors), then you will need the part "GPUSB-AH". He also sells the flat guide port cables in 7 to 25 foot lengths. There are also coiled guide port cables that he sells but do yourself a favor and avoid them - IMO they always put strain on the connections and always seem too short because they are continually trying to coil up.

#5 David Pavlich

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Posted 20 April 2009 - 09:39 AM

I use the SSAG in an 8X50 finder. I connect the SSAG directly to the Guide Port. I then have the USB cord into a powered hub, then from the hub to a USB port on my laptop. If my laptop had more USB ports, I would eliminate the hub.

As already asked, which version of Gemini do you have? Your Orion 80 should be fine. I've also used a TMB 80/480 successfully.

David

#6 Freddy WILLEMS

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Posted 20 April 2009 - 02:18 PM

This is de Gemini I have, I thought it was the leatest model because it's only around 2 years old.
So what is your suggestion to guide thru a laptop ?
With a camera attached also thru the laptop ? and PHD guiding.
Freddy

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#7 David Pavlich

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Posted 20 April 2009 - 02:37 PM

I just went outside to make sure that what I outlined above was correct.

SSAG to the Autoguide port.
SSAG USB cable from the laptop to the SSAG.
That's it! The SSAG gets it power from the USB cable so that's the extent of the connections.

In case you don't know the drill to connect, first, goto the menu tab at the top and select "On Mount"

Then click on the camera icon in the lower left and select Starshoot. You're supposted to then click the telescope icon to ensure that the mount and guider are connected, but with my Gemini, it automatically connects the two.

I then select a 2 second exposure loop, find a star, stop the exposure loop, click on the PHD icon and watch it do its thing. I hope this helps!

David

#8 Freddy WILLEMS

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Posted 20 April 2009 - 02:56 PM

Thanks David, Jeff amd Charlie.
Maybe my Gemini was not programmes in Photographic mode.
I re-set it in All speeds and try again tonight, if the weather cooperates.
PHD guiding connects fine over the RS232 port, but I was concerned that the mount did not follow the software because of some star trailing after 3 minutes.
The mount is really good aligned in the E and S, I actually never checked it out in the North, I used to use my Meade 14" forksetup for that part.
Thanks guys for the help.
Freddy

#9 hersey0308

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Posted 20 April 2009 - 05:06 PM

hi freddy - i can tell by the on/off switch that you have a newer model. the older ones went left to right. you should be able to access photo mode - have a look in the manual.
also you might consider taping over the ports and vdc out that you are not using to keep moisture out of the unit.
david

#10 Freddy WILLEMS

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Posted 20 April 2009 - 06:05 PM

Thanks David,
I did tape it all, but took it off for the picture.
Freddy

#11 Freddy WILLEMS

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Posted 20 April 2009 - 07:24 PM

I was reading the Gemini manuel a bit, and I just want to make sure that you can use the autoguider port directly to your laptop/computer to use it with guiding software ?
If so then I will buythat cable.
Thanks
Freddy






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