GPUSB vs LXUSB/LXCNV-SAC7

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BHFG
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GPUSB vs LXUSB/LXCNV-SAC7

Post by BHFG » Wed Sep 07, 2011 11:20 pm

Doug,
I am a newbie to astroimaging and trying to figure out what I need to get going. So I hope my question here aren't too ridiculous.

I am planning to use a SAC7 CCD as an autoguider on a LX200GPS 10" with PHD as the guide software. As best I can tell, that software will work with either the GPUSB or LXUSB. My guess is that PHD allows the user to re-define pins 3-6 of the LXUSB to control RA/DEC instead of their standard definition. The pinout it self seems pretty much identical, its just how the software uses it.

If that is true, then I think the difference between using a GPUSB and using a LXUSB/LXCNV-SAC7 would be that the LXUSB/LXCNV-SAC7 solution would not only give me the ability to do autoguiding, but also the ability to use something like AstroVideo or ImagesPlus to do long exposure control on the SAC7 for CCD imaging. Is that correct?

Would this be the proper configuration for each choice?
1) GPUSB (guideport control only)
PHD/Laptop---->GPUSB-----><standard 6-pin cable>----->LX200 Autoguider port

2) LXUSB/LXCNV-SAC7
A) Guideport Control
PHD/Laptop---->LXUSB-----><standard 6-pin cable>----->LX200 Autoguider port
B) SAC7 Long Exposure Control
AstroVideo/Laptop----->LXUSB--->LXCNV-SAC7--><standard 6-pin cable>----->LX200 RS-232 port

OR did I completely misunderstand how all this works?

Thanks,
Rick

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Re: GPUSB vs LXUSB/LXCNV-SAC7

Post by dpanderson » Thu Sep 08, 2011 6:04 am

Rick,

I am not aware that PHD will allow the LXUSB to be used in place of the GPUSB. It does allow the LXUSB to be used to extend the exposure time of your guide camera, but this is not the same as using the LXUSB to drive the guide port.

While the hardware for the LXUSB and the GPUSB are identical, the firmware running inside them is different, and the software drivers that are loaded on the PC are completely different.

Even if PHD could use the LXUSB instead of the GPUSB for autoguiding, you would never be able to use one LXUSB simultaneously for both autoguiding and long exposure control.
Doug Anderson
Shoestring Astronomy
http://www.ShoestringAstronomy.com

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