pmlogg

I also enquired SBig recently about a camera issue. Initially they just said to send it back. When I told him that it was from the UK he gave me some things to check, including the external power supply and the usb cable. Running a short cable and from the 12V supply rather than the 240V one it seemed to be operating the shtter fine (his initial diagnosis). I've been waiting for a clear night to test further before deciding whether it needs to go to California. I would agree with using a courier to send the camera for a US repair. The Post Office did not have a clue and had none of the correct paperwork. UPS (I think it was) or DHL was spot on. I did get charged VAT on the repair cost - which involved new parts but that is what is supposed to happen.

I find that sometimes my plastic pipe, which is much longer than yours, becomes flattened. That's how it looks when I have to empty the tank. I squeeze it back into shape and then it's fine for some time before having to do it again.

I forgot to include the diagram of the pier base from that article. Here it is.

Here are three photos and the diagram of the underfloor supports. You can just make out the hinge close to the pier in one of the interior images and the cut for the other hinge (hidden below the floor) in the other image further along the same board, just at the bottom of the frame. When I looked back at my notes I see that after cutting the flooring boards to length I laid them out on our patio and used a long piece of string secured in the centre and marked out the curved cuts at the outer edges of the boards. For the cabling the power is an armoured cable; the electronics through drain pipe. The cabling runs from the house (my warm room is under the stairs) to the pier under the 3m stone circle and then from there under the floor to the desk area.

Sorry for the delay in replying but been under the weather for a couple of days. My pier is metal, made by a local welder from pipe then powder coated. The pier support is poured concrete using measurements from a Sky-at-Night article on DIY domes. Not being very good at just doing carpentry on the hoof I used a spreadsheet to work out the decking panel lengths and "2x4" supporting framework and I did a diagram with the parts numbered. My dome is the 2.7m version so the measurements will be different. I did the wood cutting and preparation during a good spell of weather in the late spring, before the dome arrived. I used end-grain preservative on all of the end-cuts as well as the screw and cabling holes and used normal decking preservative for the flooring. I numbered the support sections as per my diagram, having it in mind that it might someday have to be re-assembled elsewhere. Once the dome arrived and was put together I assembled the floor inside, using screws. I did have to make some adjustments, including slots to accommodate the flanges between each of the four dome wall sections, and a bit at the door - but overall I was pleased by the fit. The cable access decking board has a hinge at the pier end and another in the middle. It's well supported by the sub-structure so is as stable as the rest of the floor. The pier is boxed in, for fitment of power boxes etc., with weather-proofed plywood but with access holes for cabling. It doesn't touch the pier, to avoid vibration. I made a hexagonal plywood table top which goes around the pier at the top, on which I can rest bits and pieces - the only problem I did have later was potential contact at high elevations (I'd bought a longer telescope). So I extended the pier by 30cm. The 'desk' top at the pier wall was a thing I bought to use when sitting on a couch with a laptop, painted black. I sandwiched the wall flange nearest the door with vertical 2x4 and then attached plywood to it for more cabling/power boxes and lights (one red, one white). I used scraps from the decking panels as supports for the desktop itself. Originally I used a small self-standing screen which sat on the desk but that's been replaced by a larger screen on a hinged wall mount, attached to more wood sandwiching that same flange but above the desk. A desk light attaches to that too. Again I did an excessive number of drawings too plan out the pier surround and desk but both have worked without need for modification. The only down side with the floor is that there is a potential to lose small items between the floor boards (I left narrow gaps for ventilation). Having learned that lesson I have a thin rubber-bottomed floor matt that I can put underneath when working with anything small enough to be lost. I have images on my home computer. I will find them this evening.

Concerning bases and decking, I bolted mine down onto a sandstone circle just a few inches bigger in diameter than the dome. It was laid after a central cube of concrete was poured for the pier attachment and the cabling trench completed. I just left out the central circular stone. The theory was that if we move I 'just' need to cut the bolts for the pier, remove or seal up the wiring and install the circular stone - to produce a circular patio. I have decking but inside the dome, producing a floor raised above any ingress of water and allowing cables to be laid under a hinged decking board. The cables connect a desk at the wall with cables that come into the dome at the centre, by the pier. After quite a few years the internal decking has only needed to be brushed off. I like it as it feels much warmer than concrete and I suspect warmer than rubber tiles too.

The current version Pulsar 2.7m appears to have a 700mm shutter. The original version was wider at 780mm. I've not tried side-by-side; I have one piggy-backed on the other, but the total height of the pair is less than your biggest scope. Of course when your scope pair is on one side or other of the mount the two scopes would no longer be side by side, but at the extreme would be above each other, reducing the effective width.

For Canon cameras that do not have wifi but do have a usb socket, e.g. the 450D, VirtualHere could be an inexpensive solution. I am using it for observatory control with a PC and if using the software to provide a single wifi usb link it is free, the $49 cost is if using it for multiple usb connections. You do need hardware to act as a one-port wireless wifi router and power for it. VirtualHere recommended the GL-MT300Nv2, available recently on Amazon for £17, which works fine for me. Add a powerbank to provide usb power out and that's it. The people at VirtualHere in Australia were very helpful, even though it was the free version I am using. However the one downside is that the wireless router forms a one-to-one link with your computer so no concurrent wireless e.g. internet connection. Peter

Many thanks for those good wishes. I have been keeping an eye on shutter plan. The 2-part shutter on my dome does complicate matters, requiring another motor and extra limit switches. My thinking has been that having my VM110 already moving with the dome, and being linked by wifi to the controlling computer, should make hard wiring to the VM110 possible. Perversely linking the cloud and rain sensors would be made harder. Thanks Peter

Hugh and Alan Finally some clear sky tonight so I was able to give it a good test, not imaging but just slewing onto different targets. I had to increase the GEM offset figure in POTH to get closer to the mid-point of the shutter but other than that the slaving seems to be working exactly as required. It's such an improvement from having to hold down the button on the key fob while the dome slewed to a new target. Also positive is that the VM110 and GL-MT300Nv2 seem to draw very little power so that the power bank re-charges very quickly. On current performance I don't think that having those components powered by a battery is going to be an issue. A cold winter night's imaging will be a better test though. The Wifi link has been glitch-free too. Thanks Peter

Alan Thanks for that, and again for your help. The pillow bearing is at an angle as I slightly mis-calculated when drilling the hole for the shaft through the casing. The Igus pillow bearing insert is a ball so the angle I've mounted it at makes no difference to its operation. It's there to support the encoder wheel shaft rather than exposing the encoder itself to radial forces. The two shaft bearings are also from Igus and of similar format, i.e. balls within a housing. The speeds of rotation are well within the tolerances of the bearings which do not need lubrication and won't rust. If I'd not managed to get the alignment sorted I had thought to add a second pillow bearing in that space but it would have required moving the encoder bracket backwards - and space is limited for that, or start again with a new enclosure but that would have been a lot of extra work. Luckily using the adjustment that was there with more care than the first time round did the trick as far as smooth rotation was required. I should have done more from the start to restrict axial motion of the encoder wheel shaft as I did wonder about it earlier in the process. It looks a bit Heath Robinson with the attached brackets for the Hall Effect Switch and the 2nd shaft bearing but it seems to work. In terms of cosmetic appearance I'm happier with the enclosure box for the relays and VM110. The three cable entry points have worked out pretty well. I think there is probably enough room in the enclosure for more relays if I do, in the future, want to try shutter automation. However, with the need for things to be switched on, uncovered etc. and my fear of depending on the system reacting quickly enough to close in the case of rain a powered, automated shutter is a low priority. My next stage will be to verify that the data I put into Lesvedome in respect of the mount geometry is accurate enough to maintain alignment shutter to telescope. Thanks Peter

The Hall Sensor, tested with a spare magnet, registered under the K8055 programme so the encoder box was refitted, Lesvedome run and it works with the resetting to the Home Setting taking place when the Hall Effect Switch rotates past the fixed magnet. There was no time tonight to check a slaved slew nor that the other parameters I entered into Lesvedome are accurate enough for consistent alignment. That for another night. Here are pictures of the revised encoder enclosure internals and externals. I used a longer shaft which goes through the new external bracket. The space for the wheel is such that the shaft bearings above and below act as a proxy set screw, removing all but a fraction of a mm up and down motion. Also shown is the complete system other than the original Pulsar/Rigel keyfob and receiver that form the 'manual' system. The switches on top of the original Pulsar/Rigel unit are 3-way. Pushing outwards to the dome connects the new system to the battery and rotation motor. The middle position is off and the inwards positions connect the original Rigel circuit board etc. The wall mounted box contains the Velleman VM110, the relay board, UBEC 12V to 5V regulator and the connections DB9, USB and XLR for 12V from the battery and to the rotation motor. On top of the Pulsar/Rigel unit is the Powerbank and the GL.iNet GL-MT300N-V2 Mini Router. They are brought indoors for charging. Protruding from the bottom right of the Pulsar/Rigel unit is the Encoder enclosure with tensioning spring, and DB9 connecting cable. Just to the left of it, on the dome wall is the fixed magnet. It remains to be seen if the wifi link can run without dropouts but so far the signs are promising.

The revised encoder enclosure with additional shaft bearing, plus extra effort on achieving alignment encoder shaft to encoder wheel shaft has been working. I had to adjust spring pressure to avoid the wheel coming off the dome wall in one part of it. So angle measurement from the encoder and slaving via Levesdome + POTH seems to be working. My measurement of dome diameter was only out by 2.1mm due to luck I'm sure. However for some reason the Hall Effect Switch wasn't reacting when passing the home position magnet (which was within range, and correctly oriented). My initial thought was that I might have a lose wire on one of the Switch's connections or that the diode in the circuit between the VM110 Digital Input 2 and the Switch's output might be blown. The diode checked out as did the wiring continuity checks. So all I've been able to do is tighten up the connections and will try again. If that fails not quite sure what to check next as everything else was working in the dome and during the indoor bench tests the Hall Effect switch was registering fine.

Hugh Thanks for that image and the explanation. Yours is a much beefier encoder wheel shaft than mine (6mm). I had a look to see if there were bearings like yours available for 6mm but the smallest size was 8mm - however an option could be an 8mm to 6mm bore adapter - which Huco make. There looks to be just enough space in my enclosure for one of the 8mm pillow bearings so I'll give that some serious consideration. In the meantime I've fitted the board with the VM110, relays and UBEC into the enclosure on the dome wall and connected up the motor and battery. The test with Lesvedome user interface worked fine, wirelessly from the indoor computer, as it had done when inside with the model motor. I even managed to have CE /CCW correct. So the encoder set up looks as if it maybe the last major hurdle. The replacement encoder should arrive tomorrow but with family visiting this weekend I may not be able to make very much progress. Thanks Peter

The Pulsar/Rigel rotation drive on my dome has a guide wheel which look pretty much the same as yours and it is 50mm diameter - but not sure about the bore; most of the Pulsar bolts, e.g. for the rollers on mine (quite different from those in the image) are 8mm and Paddy's photos look like they are probably 8mm.

How about these as replacements? https://www.castors-online.co.uk/acatalog/80mm-Blue-Elastic-Rubber-Wheel-Only-with-12mm---Roller-Bearing---Bore-PL50WVGRBJM6.html?gclid=EAIaIQobChMI35XfqbXL4wIVTbTtCh0WKwYKEAQYASABEgKef_D_BwE

As an update, back from holiday I fitted the enclosure for the VM110 and relays and did a test of the new encoder box with spring tensioner. Unfortunately the test did not go well but at least I think I know why. The encoder wheel is at the bottom of the box when it is fitted and although I have two bearings what I didn't have was anything to prevent tension or compression along the shaft of the encoder wheel passing those forces onto the encoder. I suspect that the combination of some residual misalignment plus push or pull on the encoder shaft caused it to seize. I've had a look at the design and plan to add a bracket with a bearing for the lower end of the encoder shaft to eliminate those axial forces plus an extra pillow bearing within the box. Just waiting now for delivery of a replacement EM14 encoder and more aluminium angle plate; the bearings have arrived. The older version of Lesvedome is installed and working fine with the set-up and I now have my permanent license. I also did some tidying up of the wiring, reducing the length of the cables - so its the mechanicals rather than the electrics or electronics now holding up the show! I'll post a picture of the revised box once completed. Peter

I tend to use stainless for everything astronomy and could never find a UK source. However Losmandy sell press-on plastic T handles for 3/8" UNC socket-head bolts. From their price list: T HANDLE 3/8 PLASTIC PRESS ON TEE HANDLE FOR 3/8 BOLTS $1.00 http://www.losmandy.com/pricelist.html That's what I use. I suggest buying more than you need as I certainly broke one in the process of pressing it on to the bolt head. If the postage seems too high you could perhaps email to see if they can send at a lower price via normal US Post Office in a jiffy bag rather than Fedex etc. I've done that with US suppliers before.

I'm not familiar with the Nexdome but my Pulsar dome it is bolted down - in my case to a stone circle. Normal outdoor sealant was used around the dome base, that could use being redone. The centre stone of the circle isn't fitted and the connection, pier to support, is below floor level. The theory is that when we eventually move the bolts will be cut off below ground level, the gap filled and the centre stone fitted. It will have several bolt holes to be filled too but those shouldn't be too unsightly. I had the pier fabricated by a local welder. He welded a section of steel pipe to a flat plate drilled to match stainless threated rod coming up from the concrete pier base - separated from the stone circle. The top was closed off and drilled to accept a pier adapter. I had the whole lot powder coated locally. It's been fine. For flooring I used standard decking boards on top of a framework of 5cmx10cm boards. That produces an air gap underneath allowing cables to be routed under the floor from the dome wall to the pier. One of the flooring boards is hinged allowing access to the cables - which pass through holes drilled in the supporting boards. I like the decking as it never feels cold. I do get small spiders and slugs, under the floor, but they don't interfere with operation.

Alan and Hugh Just a brief report as time is short. The new device arrived today - I'd forgotten we have an unplanned Amazon Prime trial. It was very quick to set up with the VirtualHere software and then connected to the main computer just as easily. Testing with K8055_dome worked with none of the glitches experienced with the Raspberry Pi. Similarly I got repeated CW and CCW movement in Lesvedome User Interface. The only glitches I did get was when I hand moved the encoder wheel - then I got a stall. So when I do return to the project in July my first step will be to go to the older version of Lesvedome. I was considering the best way to mount the device either with or without its case within the space left by the now-removed Pi but it does not have standoff holes placed for that purpose. It is however so small and in its own case that I may just use it outside the enclosure, directly attached to the powerbank and just connecting to the VM110 by usb in and out of the socket on the case. Not really much extra hassle of an evening. As I wrote before I'll post again as soon as I've made further progress. Thanks, Peter

Hugh and Alan VirtualHere has said they reckon the issue is the wifi saying: "The reason is that the chip on the pi3 is not very good for wifi. You should try other boards if you can e. glike the GL-MT300Nv2 which has 2T2R and dual internal aerials." This a bit disappointing as they had suggested using the Pi. Anyway the GL-MT300N-V2 is not expensive, will fit into the same space on the mounting board and use the same power inputs and outputs. At this point I have to put the project on pause for a bit due to family reasons - a restart in mid-July. I'll send an update then. Thanks, Peter

Hugh and Alan I've been in email conversation with VirtualHere. Due to the time difference to Sydney I won't expect to hear more until a few hours from now at the earliest. I've asked about updates to the software, listed on their website and newer than my versions. The newest for the client describes it as: "Fixed - bug where ssl connection may jam if using wifi and wifi drops or goes out of range" and the newest for the Raspberry Pi end as "fixed bug where an SSL connection may lock if wifi goes out of range or drops and wifi is used between client and server" Not sure if they will resolve it but sound worth a try. In remote desktop there would be two wifi links rather than one. If the one to the mount dropped during a slew might that not potentially leave the mount moving? I have limit switches programmed but there would still be risks to dewstrap cables etc. It's a lot less problematic if the dome kept going. I've not wired in the 'dead man's' switch that is shown in some Lesvedome circuits. Thanks Peter

Alan Unfortunately wireless control at some point in the chain is an absolute necessity due to the design of the original Pulsar dome - or at least it is unless going to a completely different drive system e.g. some have used Exploradome parts and adapted them accordingly. The router was quite close during testing and reported an 'excellent' link. When I say direct I mean a usb cable from the main computer to the VM110, by-passing the Raspberry Pi and not using VirtualHere. Where I started perhaps a year plus ago was with the idea of having a Compute Stick, with a wire connection to the VM110 and using Remote Desktop from the main computer. I'd thought to just run Lesvedome on the Compute Stick while controlling the mount from the main computer. However I then reckoned that the two Ascom programmes, one running on each computer probably could not interact via POTH. An option could be to run all the Ascom software and Lesvedome from the Compute Stick - linking to the Main Computer as described above but then I would still be back to needing a wireless link, this time to the mount, e.g. by a SkyFi? As the current control to the mount via wired usb from the main computer is working fine I didn't really want to have to disturb that. So I went back to the idea of a wireless usb hub. Some used to be marketed but not any more - perhaps they suffered from unacceptable drop outs. I couldn't find any used ones available that wouldn't produce other problems like powering the hub and then found VirtualHere and a couple of other packages that are supposed to provide a wireless usb link - although I suggest the others use a local computer e.g. the Compute Stick as the remote hub. It could be that one of those might be more reliable. Although VirtualHere recommended using the Pi rather than another Windows computer I don't know whether the Compute Stick might for some reason provide a smoother wireless link. Just swapping the Pi out and the Compute Stick in would be a relatively simple operation but could introduce other issues. VirtualHere responded quickly to my email (amazing given that I'm using the free version of their software), giving me something to check tonight. Fingers crossed. Thanks, Peter

Alan and Hugh In the process of doing the suggested testing I've decided that the problem lies with the wireless usb link. During the testing I found that sometimes the K80055_demo programme was losing its connection with the VM110 and that's when the motor staying on occurred. Why that happene I don't know as the VirtualHere software kept running. So I tested with the computer connection coming direct from the computer. The sticking on didn't happen, the K8055_demo programme maintained it's connection. More importantly Lesvedome User interface successfully commanded CW and CCW rotation. So, as you wondered previously Hugh, the Raspberry Pi seemed the weak link. I had just begun typing this when I thought that perhaps it was power so I went back and connected a Y-cable taking power from two of the Pi's USB ports rather than two. It didn't make any difference. So that leaves at least 3 possibilities, but one I think unlikely. One is that there is something about the Raspberry Pi itself, the second is that it is the VirtualHere software, the unlikely one is associated with the free version of VirtualHere which only supports one USB connection. Perhaps that also effects power from the other ports , i.e. not switching the port on for power or data, but I'm not sure that is possible. So, my next action is to get in touch with VirtualHere. Their staff member that I dealt with before was really helpful so hopefully he will be able to tell me. Thanks, Peter

Hit wrong button, here's the image.