Leads and cables. How long can I go?

[Jimtom]

Apologies if this has been asked before [i can't believe it hasn't] but how long is it feasible to make leads and cables between a 'scope/ mount and a lap-top?

As a newbie I've been happy on the few occasions I've had clear skies , since getting the new gear, staying out down the garden for hours on end but I'm starting to think that come the cold nights I'd rather be indoors.

My gear needs to be about 30 - 40 feet away from the nearest door/window so my question is, "Is it do-able?" or is that length of cable going to attenuate the signals too much?

Thanks in advance.

Jim

[Pompey Monkey]

I run 10 m active USB leads from my laptop to the camera and guide scope. I have not tried longer or daisy chaining these.

The lead to the mount is standard CAT5 from the handset: I have used a 20 m length (all I had to hand!) with no issues and I'm sure it will go longer.

The real bonus, though, is the directional WiFi antenna that I put inside a window of my house pointing towards the telescope/laptop, which is easily over 30 m from the house. Once I've go a proper focus going on, I can whip the Bahtinov mask out, retreat to the comfort of my study* and run proceedings from there using windows remote desktop. This works absolutely fine with a link speed of only about 12-15 Mb/s.

* The spare bedroom.

[Marky1973]

I've happily used 5m USB cables without any perceived problems - presumably you will need to use higher quality cable the longer you go - might be worth exploring the options of running a permanent cable to the area you use, so you can be assured it is of high quality and only have short runs from the exterior socket to the outside kit....I presume this is possible, although I am no expert!

I also have thermal clothing.....

:-)

[wuthton]

Like Mr Monkey I too use Windows Remote Desktop or Chrome RD. For controlling your equipment from a distance it is the most reliable solution.

I did have a 30m network cable that I ran from the scope computer to my router but I now have an outdoor wifi access point. The wifi from your house router is unlikely to have the guts unless you have line of sight through a window.

[ChrisLX200]

I use a 15m USB cable (repeater cable) plus Ethernet cables which can be 100m if you wanted. I also use a USB>Serial converter to connect to a Losmandy Gemini control box 15m away. It's the plain USB cable which is tricky when it comes to the longer lengths and some active cables work yet others won't. If you use a USB>serial converter don't try putting it on the remote end, have the converter part close to the computer and use a longer serial cable (ask me how I know this).

ChrisH

[cjdawson]

The maximum length of the cable can be a very variable thing.   Firstly there are different kinds of cable, and quality.  I'll leave the quality part aside.

I'm going to assume 40 feet, or 12.2 meters for my back of envelope information.

Power cable - ideally keep this short as DC power will be lost over a longer cable run - that's why mains power is AC rather than DC.

Serial cable is only 5 volts, it's not a current based sitution, and the information I've had since college was that a serial cable can run for about 150 meters before it needs a repeater.  You'll be fine with that. ;-)

USB is a different story, it runs at much hight frequency than serial cables, so the run is much shorter.  The spec says that 5 meters is the limit, but as people about have said 15m can be done with an active repeater.

Ethernet cable can run for 100m in a single piece, so again, no problems there.

Overall, I think you'll be ok with it.

[ChrisLX200]

Ah yes, power cables. Use a decent gauge cable to minimise voltage drop (lower resistance). I use 2.5mm core and over 15metres it drops from 13.8 to 13.3 volts, or around 0.5v loss. That may be important if your mount depends on seeing 12v at its input.

ChrisH

[Jimtom]

Thanks for all the advice folks.

I think that a 15m USB repeater cable will sort me out initially. Power isn't a problem as the AVX seems to behave well enough with the current extension cable although I have a 22A/hr battery which I intend to use when away from home.

I've not looked into Windows remote desktop, Wi-Fi is pretty good, it's an old farmhouse with thick walls so we installed a router and extenders, that made it a bit too good and the all the girls with DIY livery [horses] were constantly using it and using our bandwidth! [ new password stopped that.]

Can I run BYE and Stellarium on an old XP laptop? It's an old Dell Inspiron dual core 1.75GHz and only 1 gig of RAM.

[Pompey Monkey]

Can I run BYE and Stellarium on an old XP laptop? It's an old Dell Inspiron dual core 1.75GHz and only 1 gig of RAM.

Suck it and see? lol!

And don't forget to let us know how you get on!!!!

[brrttpaul]

Glad someone posted this as I was thinking the same thing, I went on amazon last week and looked saw one 10 metres long (fire wire i think) and it had good reviews for astrophotography etc so i ordered one. the plan is set it up out the garden then run it through my laptop in the kitchen with BYN and CDC