View Full Version : Extend the USB cable lenght?

Phil RixAstro
November 1, 2009, 11:21:34
Hello, I am the owner of a "DMK 31 AU (usb 2) and I'm very satisfied with the results for astronomy, particulary for planetary imaging. However, the lenght of the USB connection is a real problem:I can drive my telescope from indoors, at a distance of about 8m. from the outdoor column but I cannot use the camera (i.e. for guiding) by usb from the same distance. Are any modifications available to add an external electrical power entry to the camera (like many astronomical cameras) or could you suggest another solution in order to add another five or six metres to the current three meters limit? Does the factory do this work? Would it be very expensive to go back to "fire wire"? I should be grateful for any help or advice. Phil.:-)

Stefan Geissler
November 2, 2009, 10:01:34

the electrical power is not the problem, but the maximula cable length for data transmission is limited. You may try an active USB hub to extend your cable.

November 2, 2009, 13:31:21
That can be done. I know a fellow in Arizona who wanted to run USB about 50 feet to his observatory. He used some sort of amplifiers and powered hubs.
You could probably fine info on the internet or maybe talk to some knowledgeable folks at a computer shop.
I run everything, cameras included, in my observatory from about 120 feet away with a simple Cat5 cable network and use the free program RealVNC to control the laptop from my desktop in the house.
There is a slight delay in data transfer over that much Cat5 cable (the max is 300 feet) but it's so minimal that it's hardly noticeable.

Stefan Geissler
November 2, 2009, 16:50:52
For bigger distances you may should switch to GigE cameras. Then you do not have problems with cables up to 60m.