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Old 10-10-2012, 01:49 PM
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multiweb (Marc)
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Question Thin or Flat cables

I'm trying to work out a system of spider vanes for my hyperstar so what I'm after is any USB or power cable that can be stripped down to the bare minimum and make them appear flat to avoid excessive diffractions spikes. I believe RCs and other high-end telescope have that kind of cabling running along the secondary vanes for heaters or focusing mechanisms.

So what do you reckon is the best way to achieve this? I also read somewhere here that flocking a spider vane with thicker anti-reflective material (like velvet) would reduce light diffraction, although the thicker layer would somehow impact contrast in the final picture. If it is true I could wrap standard cables into flocking? Would that work?

Or maybe have one big curve support. But that would be harder to center the hyperstar. I want to be able to center the camera to take the weight off the corrector plate.

I don't know which way to go at this stage. I'm interested in opinions and possibly experiences. TIA.
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Old 10-10-2012, 05:57 PM
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MrB (Simon)
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The cable I have seen used on the high end scopes is known as ribbon cable. This can be bought from electronic retailers like Altronics and Jaycar, bought online or salvaged from old computers (IDE and SCSI drive cables)
Most ribbon cable is grey, tho there is also Rainbow cable which is very pretty tho not what you want, I have never seen black so flocking would be wise.
It comes in different gauges, but most is pretty light gauge, meaning for high power items you will need to use many lines in parallel to carry any serious current.

I'm not sure you would be able to use it for running USB though, maybe it can be done for short lengths like spider vanes.
Using ribbon cable means all the lines are obviously in parallel, which is bad for high speed data. Usual practice with ribbon cable(like IDE cables for harddrives) is every second line is grounded in an attempt to reduce crosstalk between neighbouring data lines.

Last edited by MrB; 10-10-2012 at 06:15 PM.
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Old 10-10-2012, 06:45 PM
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multiweb (Marc)
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Cool. I got plenty of ribbon cables from old IDE drives and floppy disks. I saw some USB ribbons but they're all to mini USB and mostly for Samsung devices and other mobiles.
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Old 10-10-2012, 07:00 PM
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Bassnut (Fred)
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Flexible PCB is the thinnest , less than 0.5mm, but unnecessary, my RCOS has stand up ribbon cable which is thinner than the spider. A bit of work to wire but doable and not hard.
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Old 14-10-2012, 02:04 PM
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MrB (Simon)
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Quote:
Originally Posted by multiweb View Post
I saw some USB ribbons but they're all to mini USB and mostly for Samsung devices and other mobiles.
Sorry Marc, I did see your reply when I was at work but didn't have time to post.

I reckon you should have a go at routing the USB thru the ribbon, I don't think such a short run will be a problem. If it were me, I would simply cut a good quality shielded USB cable and solder the ends to either side of the ribbon.

USB cables have only 4 wires, Red(+5v), White(Data-), Green(Data+) and Black(GND)
If you space the Data+ and Data- lines with a ground (or two if you have enough spare lines), you should have no drama's. Maybe some ali foil shielding over the ribbon too, connected to GND at one end only.

If it doesn't work well(I'll be surprised), you're only out the $ for the cut USB cable.

http://en.wikipedia.org/wiki/Univers...cal_appearance
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