Managing the cable tangle.

[Geoff45]

I have been looking at Mike's pics of his equipment (http://www.iceinspace.com.au/forum/showthread.php?t=25530)and couldn't help but notice the cables everywhere. A while ago I had the same problem and something always seemed to go wrong during the session. I gave it some thought, and when I tried the new setup, I had my first night of imaging when absolutely nothing went wrong and everything worked as it should.

The basic trick is to run all the wires to where the Dec portion of the mount joins the RA portion. Make a loop here, and fix the two ends, one to the Dec and one to the RA axis. The loop should be long enough so that it will not stretch to the limit in any direction. Test this by moving the mount around to see if there is enough slack. I then run all the cables for the computer through some washing machine hose. The others run straight down to the battery box.

Another useful trick is to stick velcro strips on the tripod legs at strategic places and also on the back of things like hand paddles, remote camera controller etc, so you just plonk it on the mount wherever convenient
The pics should make things clear.

Taking the shoulder strap off your DSLR also gives you one less thing to worry about.
Geoff

[[1ponders]]

Gotta love that reusable Velcro wrap :thumbsup:

[iceman]

Looks great Geoff, I really should be tidier :)

You've inspired me :)

[gbeal]

Yep, I am, similar, tidy is good. One thing though. I like the DSLR strap on. Partly cos I actually use it during the day, and mostly as I slip it over the finder stalk or similar, that way when the set screw loosens it doesn't get to the concrete.
In keeping the wires tidy, I do wonder if I am introducing noise with running my USB cable next to the power cable. No real reason for wondering this, just curious. Some say it can.
Gary

[Lee]

I just bought a 5m roll of that velcro wrap!

Does anyone know if 12V DC cabling introduces noise/interference in adjacent wiring??

[Dennis]

Hi Lee

Just in case, I keep all the signal cables bundled together and all the power cables bundled together, on opposite sides of the mount. Examples are:

SIGNAL CABLES:

ST7 Parallel cable.
DMK Firewire cable (although it also provides power).
PC to Mount RS232 GoTo cable.
CCD to mount auto guider cable.
CCD to PC auto guider cable (GPUSB)
DSLR USB cable.

POWER CABLES:

Mount.
CCD Camera(s).
Dew heaters.
Motorised focuser.
DSLR power cable.
Illuminated finder scope LED power cable.

Cheers

Dennis

[montewilson]

Hi Lee - this approach would help but only if there really is interference coming from your 12v cables. If they are running from a good power supply or even better, a battery they wont be the source of your interference. I have all mine bundled together and no probs.

That is power for STL, STV, 24v for mount and 12v general power, USB for STL, Serial for Robofocus,STV and Temma mount and STV camera cable, all in one bundle.

You could consider putting a choke on the some of the lines to try to eliminate which cables are causing probs. Jaycar have them and they clip around cables and will remove HF from DC lines.

[Dennis]

Hi Monte

Thanks for the info re chokes etc. that’s useful information to have.

So far, (touch wood!), I haven’t had any EMI/EMC problems (apart from a wireless mouse and Notebook mains adapter interaction) but I did once read about an early model Kendrick dew controller (MK III?) that may have been the source of interference for ccd imaging, so I just keep my signal and power separate as a general practice.

As I have to set up and tear down each night, I’ve just got into the habit of running Power on the RHS of mount and Signal on the LHS of mount.

Oh, just remembered, I did get a circulating current in my auto guider cable once (Skysensor 2000), from a (3rd party) PSU, the result of a slipped heat sink on an internally mounted metal cased transistor power device shorting to the metal chassis of the PSU!

Cheers

Dennis

[Lee]

Thanks Monte - I haven't had any probs so far.... I can't effectively separate signal/supply easily, as everything runs from computer area to pier through some 54mm PVC pipe.
I have been trying to keep any 240V AC lines clear of signal cables though.