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gnomus

By gnomus
in DIY Observatories

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gnomus

gnomus

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I bought one of these DC Moonlite focusers.  It was reasonably easy to fit - and it seems to work well.  It is on my ED80 at the moment and I will almost certainly pick up another for the Edge HD8.

The latest thing to trouble me is:

Cabling

I am having a pipe fitted under the floor to run from the telescope pier to the warm room.  There are a lot of cables that will need to be run.  Let's see...

Power from Maplin PSU to mount

Cable so that I can control mount from laptop (using CdC/Stellarium)

Cable for focuser

There will also be a heap of USB cables:

USB 3.0 for ASI 120MM-S

USB for filter wheel (not quite decided, but probably an EFW 2)

USB for DSLR Camera (Canon EOS 600D)

USB for future CCD Camera (not quite decided, but probably a 460 EX)

Have I missed anything out?  

With regard to the USB cables, am I better to run one cable (possibly two cables) and connect all the devices in the observing area with a USB hub of some sort?  I assume the USB 3.0 cable would need to be run separately.  And on that subject, I once bought an extension USB 3 cable for my ZWO (running in through kitchen window) - it didn't work - NADA.  Does anyone have any suggestions for cables, hubs and so forth that will withstand outdoor use? 

Some ideas on cabling layouts would be most helpful.  Is one conduit pipe going to be enough?

Thanks in anticipation.

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gnomus

gnomus

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OK - a brief update.  We're all ready for concrete, which should be coming tomorrow.  The shed itself should be here in a couple of weeks.

post-39248-0-74106700-1434652413_thumb.j

I'll upload another picture once the concrete has set.

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Dr_Ju_ju

Dr_Ju_ju

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Hi Gnomus,

As to your question regarding USB extension cables, depending on the USB type 1\2\3 then there are limits on the length that can reliably be used... 

I have found 5 metres max for USB 1\2, but only using heavy duty cable and the device being connected, having a separate power connection. For USB 3 the max I've gotten away with is only 3 metres and this was really iffy, also with a separate power supply.

It is possible to reliably extend USB by using USB to Ethernet converters, but these can be expensive...

Another approach would be to site a controlling computer closer to the mount, this is the approach I have taken, I then have multiple Gbit network connections back to the house...

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gnomus

gnomus

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Not sure if I'm to late with this suggestion but always a good idea to pull a couple of spare strings/ wires through incase you need to add at a later date

Gareth

Not too late. I was speaking to the Home Obsevatory UK chaps yesterday and I have decided to have a second 45 mm conduit pipe fitted. I had rather assumed that when you 'pulled through' one of the USB/power cables you would attach a fresh 'pull through' string with it. Also, someone suggested the plastic line that you put in grass strimmers made for a good pull- through string.

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kirkster501

kirkster501

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Not too late. I was speaking to the Home Obsevatory UK chaps yesterday and I have decided to have a second 45 mm conduit pipe fitted. I had rather assumed that when you 'pulled through' one of the USB/power cables you would attach a fresh 'pull through' string with it. Also, someone suggested the plastic line that you put in grass strimmers made for a good pull- through string.

..as does cheap nylon washing line.

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gnomus

gnomus

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God luck on the concrete pour tomorrow Steve.

Thank you, Steve.  It seemed to go reasonably well.  Here is a pic early on into the process (yesterday):

post-39248-0-13135300-1434784866_thumb.j

It is looking pretty good this morning, but I won't upload a photo until I get all of the wooden shuttering off (early next week).

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Scorpius

Scorpius

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I believe they are using something called a chembolt

Ok I see - wasn't aware of this solution for a bolt on pier but looks like it should offer a secure connection and vibration resistance which is always a good thing :)http://www.automatedfastening.com/ProductsPage/ChemicalAnchors/Powers/SupportFiles/Chem-Bolt.htm

I've opted to embed my pier into the pier plug which means they'll be no way to remove it later unlike the bolt-on approach you are taking. This makes me a little nervous but I'm hoping for a rock-solid pier with as little deflection as possible. Progress has been slow so far due to multiple factors but think I'll be able to start a build thread of my own pretty soon. I plan to do all the work myself as I can't afford to hire it out and I'm never satisfied unless I do it myself anyway :)

All I've managed so far is to dig the hole and weld some rebar on the bottom of the pier pipe for extra stability. I did purchase an aluminum adapter plate to fit my mount (Advanced VX) and am currently on hold until the machine shop completes the 1/2" steel baseplate that gets welded to the top of the pier and accepts the adapter plate made for my mount. This part I couldn't do myself since I don't have the right tools and it has to be very precise so everything will fit. The plan is that I'll be able to switch mounts in the future by getting a new adapter plate that will fit the baseplate I'm having made without further modification.

Anyway, didn't mean to hijack your thread and good luck moving forward. I'll be following your progress with interest and have a feeling you'll be done long before me... :)

Cheers,

Scorpius

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post-37916-0-43373200-1434891150_thumb.j

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gnomus

gnomus

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No problem. I watched the guys laying out, tamping down, and trowelling the concrete. It was quite an eye-opener. A job requiring way more skill than I have, that's for sure.

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gnomus

gnomus

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I've been thinking about lighting inside the observatory. I intend having lighting in both areas so that I can undertake general work and maintenance in there.  Is there any advantage to having any form of red lighting?  

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gnomus

gnomus

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Power

I've been purchasing some bits and pieces in anticipation of getting the new observatory up and running.  I now have an Atik 383 and an EFW 2.  For a little while, I have had the following power supply: http://www.maplin.co.uk/p/maplin-97w-dc-fixed-voltage-bench-power-supply-xm21x

This gives out 5A (but can peak at 9A).  Unfortunately when I added together all of the amps required by my various bits and pieces, it came to a little more than this.  I calculated as follows: 383L - 2.5A; EFW2 - 0.3A; CGEM Mount - 1.5A; a couple of dew bands - up to 1.8A.  (These figures mostly came from the manuals, the heater bands I measured directly with my ammeter.)  That comes to a shade over 6A.  I did notice that when I was playing around in the house with the gear there was occasional erratic behaviour from the camera or the filter wheel.  For example, the camera didn't seem able to get cold enough when everything was connected, it did so quite happily when it was the only thing connected to the power supply.  I wonder if the lack of amperage is going to be a real issue, therefore.  

I've looked back at Maplin's website (where I got the original power supply).  I have found this model, which would seem to be more than adequate.  http://www.maplin.co.uk/p/375w-linear-dc-variable-voltage-bench-power-supply-rp10l

Before handing over the readies, I thought I should check on here that this was the right direction of travel.  Has anyone else used this particular power unit and, if so, how would you rate it?

Thanks in anticipation. 

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gnomus

gnomus

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If you need more power try this unit, also from Maplins:-

http://www.maplin.co.uk/p/207w-switched-mode-dc-fixed-voltage-bench-power-supply-n31gk

Steve

Thanks Steve.  I did see that one, but in my research I did come across some stuff about Linear Mode power supplies being more suitable for this application than switched.  I don't even know what that means, but that, plus the extra power in the second unit I quoted, made me think it might be more suitable.  I'd be interested to hear other views, however.

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gnomus

gnomus

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USB 3.0 problems

I continue to play around with my gear in anticipation of the arrival of the new observatory. 

I am having a warm room, and this means that the laptop will be approximately 7 feet away from the telescope, "as the crow flies".  In reality, by the time I have gone down the pier, under the floor and up to the desk, the run is going to be somewhere around 12-13 feet minimum.

At present, I have a powered USB 3 hub.  I have an Atik 383L, an EFW 2, and a ZWO ASI120MM-S.   I have a reasonably new laptop with one USB 3 input and 2 x USB 2 inputs, one of which has a mouse plugged into it.  Here is what I have found so far:

1) The mount

The mount does not seem to like being plugged into the USB hub.  I get erratic behaviour and lost connections.  If run directly into the spare USB 2.0 port on my laptop it appears to work flawlessly and I can control it within CdC and SGP.  I am going to get a phone line extension for the mount and run it that way.  

2) Atik Gear

This appears to work well with both the camera and the wheel plugged into the powered USB 3 hub, so long as I keep the lead from the hub to the laptop at no more than 3 metres.  When I tried a 5 metre cable (http://www.amazon.co.uk/gp/product/B004V74B0S?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00 ), I could control the wheel and the camera, but the camera would "hang" as it tried to download an image to the laptop.  I also tried one of those "active repeater" (http://www.amazon.co.uk/CSL-repeater-extension-amplification-amplifier-C-USB-3-0-black/dp/B00MPMFKSI/ref=pd_sim_147_1?ie=UTF8&refRID=0D0S2PGMSH33DP8Q5ZP8) cables between the hub and the laptop, but this gave me the same problems.

So I can stick with the 3m cable, but I don't think that this is going to reach.  I have tried reading about USB and USB extensions.  I am not sure that I am any the wiser.  I am tempted to try another 5 metre cable - these cables do get varying reviews on Amazon.  However, I am struggling to see how a piece of wire and some plugs (which probably are sourced similarly) can function differently depending upon who sticks them together.   Another option might be to "daisy-chain" two powered USB 3 hubs (I think that the 3 metre cable will reach the warm room but will not be long enough to get up to the desk).  I have seen this on Amazon (http://www.amazon.co.uk/ORICO-Ports-3-PIN-Adapterand-controller/dp/B00A77ZE98/ref=sr_1_5?s=computers&ie=UTF8&qid=1435641086&sr=1-5&keywords=orico+usb+3.0+hub).  My other USB hub is also made by Orico - http://www.amazon.co.uk/Aluminium-External-Adapter-Chipset-Windows/dp/B00KBT8DUY/ref=sr_1_10?s=computers&ie=UTF8&qid=1435648973&sr=1-10&keywords=orico+usb+3.0+hub.  I wondered if these two might work well in partnership.

3.  ZWO ASI120MM-S

In what I have understood of the information I have read, USB 2 extension tends to be a bit more reliable than USB 3.  Why not just run a USB 2 powered hub (or hubs) then?  Well I have my ZWO to consider.  This is USB 3.  I intend to use it with the EFW 2.  Once again the ZWO seems to be able to work via the USB 3 hub, so long as I keep the hub-laptop lead at no more than 3 metres.  I can get a full-frame FPS of just under 60 this way.  If I were tempted by the (?) more reliable USB 2 option, then I would have to run a USB 3 cable from the ZWO to the laptop.  When I tried this with the Lindy cable mentioned above, the laptop didn't even see the ZWO.  So that appears to be a non-starter.

It would be absurd to start thinking of having USB 2 and USB 3 hubs.  In any event, I only have limited inputs at the laptop end.   

4.  Solutions?

I have been following this thread - http://stargazerslounge.com/topic/247092-extending-usb-30-in-the-observatory/?hl=%2Busb+%2Bextension#entry2688248, and hoped that a solution might be found within it.  The original poster has, however, settled on a USB 2 hub.  That would be no use with my ZWO.

Has anyone been able to get lengthy runs of USB 3 working?  Is "daisy-chaining" USB 3 hubs together a viable option?  Is there any point in me trying different brand 5m USB 3 extension cables "active repeater" or otherwise?

It would be nice to hear from someone who has been able to get long USB runs working, before I spend any more money.

Thank you again for your patience.

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Astroboffin

Astroboffin

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Hi,

I have had similar problems to you in the past

My pier is 10m away from my warm room, and all my cables are underground from pier to garage.

These were my findings, I had to firstly put a good powered USB 2.0 hub at the pier end, to boost all the signals before hitting the 10m USB 2 cable, which was also an active repeater cable.

The cameras that have there own power supply ran fine on this, DSLR, Atik414ex

But my Meade DSI and ZWO ASI 120 were a bit more of a problem, and I put that down to them relying on the power from the hub and cables.

I changed the hub and then all the cameras worked, but the DSI did sometimes not get recognised and had to keep disconnecting and trying again til it worked, so all in all a bit hit and miss

Then I bought a USB 3 camera, the ASI120mc-s, and this would not work at all with my laptops USB 3 port, even with the supplied cable, so a waste of money that was for me.

So I tried another laptop just to really make sure it was not my USB 3 port failing, well it worked flawlessly on the other laptop with the supplied cable, so I bought a 10m active USB 3 cable to try, and was not even recognised, tried it on just 5m and the same, on three and the same, it would only work with the supplied cable, I then put a powered USB 3 hub at the pier and still not good, so gave up.

So my conclusions are that USB 2 cameras work on 10m or less (not tried over a longer length) lengths active cables no problem if they have there own power supply, with a powered hub at the scope end of the cable.

USB 2.0 Cameras without there own power supply are a bit more hit and miss in my experience, even with a powered hub. ( although both my ASI120mm and 120mc-s work fine)

USB 3.0 cameras without there own power supplys, forget them over anything above 2 or maybe 3 metres of cable

I don't know of any USB 3 camera available that have there own power supply so can't comment on them.

I just use my ASI120mc-s over USB 2 and except the loss of frame rates, and that does work ok over the 10m cable, but why it won't work over the same length on a USB 3 cable..........I can't explain....

Hope that helps a little, although these are only my experiences other people may disagree

Regards

AB

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gnomus

gnomus

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Thanks AB, though your first post was not terribly optimistic.

There must be some solution to this.  Someone must have been able to get a 15' run of USB 3 working?

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