Observatory USB Cables vs. WiFi - Forums

Topic starter

Feb 26, 2023

Hi Folks,

Having not found any contractors willing or able to make a roll-off roof observatory, I'm building my own in my backyard. It is going to be a 10' x 16' with two piers.

My plan is to have each scope with its own computer for imaging. All wires will be run under the floor in electrical conduit to computers in the corners. Now I'm wondering if such a long USB cable from each camera to the corner computers is going to introduce a problem. Would I be better off building two mini-PCs (i.e. NUCs) that I can mount to each pier, and then stream the NUC's image feeds to tablets or laptops using a wireless router when I need to see things in realtime? Then I would download the data from the NUCs for processing to my desktop wirelessly.

Below is the electrical wiring diagram my buddy and I drew up to understand the layout (it doesn't refer to the USB cables, but I provide this for you to see the spacing of the computers and piers).

Thanks,
Ben

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Joe Linington

Feb 26, 2023

What software do you use for imaging. If you use Kstars/INDI, I would place PI INDI servers on the scopes and then run cat 5/6 to the control computers. If Windows with Nina or something else I would by a mini computer for each scope and either wifi or cat 5/6 to a router. The max cable length for USB2 is 5m (16’). Less if you need USB3

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drblevy13

Topic starter

Feb 26, 2023

I'm using N.I.N.A on Windows, so I'm thinking mini computers based on your response.

Markus R.

Mar 13, 2023 · Edited: Mar 13, 2023

I used to use a 5m USB3 cable from my laptop to an active USB3 Hub on the scope and I often had the problem that the camera (qhy183c) couldnt transfer the image, especially while guiding. When i removed the long cable, everything was fine. Now Im running a NUC on the scope thats automatically connects to a set wifi network on boot and I remote into it from a tablet/laptop with VNC.
BUT Windows loves doing updates and sometimes resets the Wifisettings or blocks VNC on boot for the stupid after update configuration. So have a monitor and keyboard readyfor the case the NUCs dont connect.

Edit: on a fixed setup like this you could connect the NUCs with a ethernet cable to your network, this is probably the most reliable.

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Rod Hughes

Mar 13, 2023

USB cables can be tricky when extended. A 32' USB3.0 cable has 2 hubs. Windows only supports 5 USB hubs in series. Practical limit for USB cable with hubs is 32'. I have gone 100' with USB over fiber without any problems. When possible, use high quality USB cables and keep them short.

Rod

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Cosmetatos

Mar 13, 2023

NUCs on the pier. (or just next to them)
wireless keyboard/mouse
HDMI cable under the floor to the monitors

Tim Ray

Mar 13, 2023

I like @Cosmetatos response, or just remote desktop into each NUC vs a dedicated BT keyboard/mouse and monitor...

CS - Tim

drblevy13

Topic starter

Mar 13, 2023

Cosmetatos, I was thinking the same exact thing! Appreciate the input form everyone.

Fabian Butkovich

Mar 14, 2023

I use an active 32ft USB 2.0 cable plugged into another regular 25ft long cable, then I have an Anker 7-port USB 3.0 powered hub strapped to my iOpton tripod that I plug everything into, the long USB cable runs through my living room window to my laptop and I can control everything from there. I haven't had any issues using this setup and it's nice I can get a long distance with this setup. The powered USB hub is crucial as trying to power any guide cameras or other 5V accessories is not possible over such a long distance. Signal integrity-wise the active cable works great and I'm able to communicate with my ZWO 183MC, iOptron CEM26 and Astromania guide camera all just fine.

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John Hayes

Frequent contributor

Mar 14, 2023

An active USB3 cable works pretty well. I've used them out to 25' without any serious problems. If I were doing this kind of project I'd use either CAT-5 connections or fiber. Both are relatively easy to set up and in that case, distance won't be a problem. I'm personally not a fan of NUC but that's just me.

John