Equipment – Cables

Linking everything up to a computer is a bit of a chore – cables seem to breed in the dark and there are often more than I know what to do with. I’ve tried to organise them somewhat, but – in the darkness – things seem to go awry.

Controller with RS-232 and Autoguider cables

Initially the controller and handset are neatly arranged, and two wires descend from the controller along the pier, one carrying the main RS232 control and command signals, the other carrying the detailed ST-4 compatible auto-guider signals. Meanwhile the handset itself is connected to the controller via a cable mounted to the side of the controller, and when not in active use is stored in the space between the main pier and the mount assembly.

Scope imaging cables

At the scopes the imagers are supposed to be securely mounted with the cables snug and out of the way. The DSI Pro mounted on the Orion Express (black scope on top) needs no additional power and is basically capable of capturing images at any time. A single USB cord travels along the scope and then down the mount. Enough slack must be given so that the mount doesn’t pull it off the scope as the mount moves, and yet not so much that it is likely to jam up in the mount itself. The cables from the Canon 40D are similarly constrained, but only one of the cables is shown here. There are three cables:

  1. a USB cable for the camera command and control,
  2. a power cable for the camera,
  3. and finally a shutter control cable for long exposures on the camera (exposures under 30 second can be controlled via the USB cable).

The focuser shown here is entirely manual, and has now been replaced by a Moonlite Focuser with a focus motor (more cables, photo to come).

Controller with RS-232 and Autoguider cables

Once the cables snake down the pier, they pass through interface boxes and join up at a USB 2.0 hub,

Controller with RS-232 and Autoguider cables

from which a single cable will ultimately connect to the laptop computer.

Or so goes the theory. In practice, the hub did not do as good a job as was hoped in connecting the electronics together, and I had to pull one cable and connect it directly to the laptop, while the other cables seemed to be erratic in whether they did or did not connect. More investigation is required to determine if there is any interaction between the software and hardware which prevents some hardware from working while other software controllers are in use. It did seem that way, but at 3 am there’s not always a deal of analytic thought going on.

The hub shown is quite spectacular, with blinking coloured LED lights in the centre of the device and a different coloured LED at each connection point:

No doubt very pretty and entertaining, but very distracting in the depths of a nighttime session. It’s been replaced by a 7-port D-Link USB Hub (C$30 at TigerDirect with a $10 rebate) which has proven to be more effective — or at least, less distracting.

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