GPUSB EQ3-2 mount Autoguider port install

Questions about hardware and software obtained directly from Shoestring Astronomy
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gtquan
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GPUSB EQ3-2 mount Autoguider port install

Post by gtquan » Tue Nov 09, 2021 8:36 pm

I just received the GPUSB module and Autoguider port conversion kit. Thought I'd share the experience. I have an old Skyscan 2001 EQ3 mount with the dual axis motors and controller that is the exact same as the one pictured in the picture from Shoestring. Just starting to get into imaging and was looking to get autoguiding for this mount. I've done 1 minute subs on this mount unguided with a William Optics z61 refractor. About 20% of the images have some star trailing - I guess that's periodic error in the mount? Skywatcher stills sells a version of this mount in various forms including one with an autoguider port and goto functionality.

The installation of the autoguider port took about 30 mins. Drilling the hole in the case is tricky as you could damage the circuit board if you're not careful - I ended up using my solder iron to actual melt through the plastic housing to expand the hole. I've threaded the cable horizontally though I think it may thread and bend better if the flat part is oriented vertically. It's a bit fiddly trying to thread the cable in and reseat the circuit board. The soldering was straight forward. Powered up the controller and everything still working. I attached the GPUSB module and windows 10 recognized it right away. Installed GPUSB check - and now can control the motors through the computer. There was an initial warning about the software which I just ignored though it said not recommend.

I haven't tested out guiding yet - I assume this is just attaching the guiding camera to computer via usb and running some guiding software now that I can control the motors with the computer. Anyway - happy so far and will see how autoguiding with this mount works. It's quite a cost effective solution for this mount if you have the motors/controller already. Probably not useful for full GOTO as I doubt the original motors are fast enough. Should make for a nice portable imaging setup for small scopes and I was able to use my decades old equipment. I did consider purchasing the EQSTAR 3 upgrade out of the Ukraine but that's almost 3x the cost with newer motors and controller. I'll update my post after playing with autoguiding.

gtquan
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Joined: Wed Oct 27, 2021 7:49 pm
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Re: GPUSB EQ3-2 mount Autoguider port install

Post by gtquan » Mon Feb 14, 2022 5:17 pm

Everything seems to work well. Set up autoguiding with PHD2. I need to work on getting more precise polar alignment. According to PHD2 I'm getting about around 2" accuracy if I'm reading understanding this correctly. It's fine given the short focal length refractor I'm using on thus lightweight mount. Curious if it can get much better or is the mount just not good enough

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