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About patm

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    BC, Canada
  1. I just installed on windows 10 today and the first (auto selection) attempt failed. After that the troubleshooter let me choose windows 7 and it all installed fine. The programs all start fine too but I haven't actually connected it to anything yet so I'm not positive it will actually talk to a telescope I have the SkyQ 2 coming and once it gets here then I'll know for sure.
  2. Those non-clear round fuses are for high voltage and a total waste of money below 120V. You could go with the round fuses and inline holders or with the newer automotive fuses. Just make sure the fuses are covered in some way. Glass/metal exposed to the sky can have shorts due to condensation which doesn't necessarily harm anything but the fuse may not blow until well beyond its rating. While very unlikely you can also get an arc from a short which throws off sparks and sparks can cause fires. Electrical code everywhere demands connections to be in rated enclosures; not so much on low voltage systems but why lose a telescope/obs/house to save a measly few dollars? By enclosure I don't necessarily mean a big box. Lots of inline fuse holders have nice drip proof tubes you put fuses into and cost just a few dollars.
  3. It really boils down to air inside the obs getting heated up during the day (which allows the air to carry more moisture) then cooling down at night past the dew point (a temp too low for the air to carry the amount of moisture it already has). A house doesn't have condensation problems because it is heated all the time. So one solution would be to keep the obs heated but beyond the price of insulating/heating is the issue of hot air currents once you open up to observe. An attic doesn't have condensation problems because it is well ventilated. During the day the air gets hot (and carries lot of water) but as the outdoors cools down the hot air escapes through vents and keeps the attic humidity pretty close to the outdoor humidity. This happens fairly quickly because of natural ventilation. Since hot air rises we put vents at the top and bottom of the space. Hot air rises and leaves through the top vents (usually in gables) causing a low pressure which draws cooler air in through the bottom (soffit vents etc). Mechanical dehumidification would work but then you'll need to a lot of sealing to see any benefit and prevent drying the great outdoors. Complicating matters is the choice of materials. metal and glass tend to cool faster than wood and other organic matter, as do thin plastics. Even worse is when they are exposed to the sky (which is -270C ish) which we're all quite familiar with due to scopes fogging up. An uninsulated metal or plastic/fiberglass roof can cause rain showers under the right conditions. So the simplest humidity control is to add venting. Both near the floor to let cold dry air in and near the roof to let warm wet air out. A solar powered fan would be a plus not just for humidity but also for faster cool down when observing. Also add insulation to any thin (non wood) panels to slow down the cooling of the inside surface and create a thermal break so its inner temperature doesn't get as low as the outer. Insulation doesn't really add a lot of thermal mass so it won't hurt cool down time all that much. My own preference is to add natural ventilation - one time low cost and usually pretty effective. I'd add a solar powered fan or two later if natural proves insufficient. That said, I also live in the northern latitudes so i rarely get those really hot muggy days (I've been to the tropics many times - believe me there's a huge difference). I think if I was somewhere down south I might go with sealing everything and adding powered dehumidification. P.S. my background is as a power engineer at recreation centers. One of my responsibilities was for dehumidification of ice rinks and swimming pools and I've lots of experience with mechanical and desiccant dehumidification. At one pool, after all the mechanical engineers were done, I added sensors, rewired and reprogrammed the system, and saved an additional 30% on natural gas (around $20,000CAD that year). Natural venting is not an option in either case because of strict temperature control requirements.
  4. Ditto on what Physopto said! Fuse everything and choose fuses that are close (but not under) the equipment rating. Fuses can be fast or slow blow so make sure you get fast for expensive electronics. Slow blow is better for inductive loads (motors, transformers, anything that has a big inrush current when first started). Your "main" fuse (between battery and distribution device) should also be slow blow since the device fuses will protect each device. Here's a war story! I worked at an ice rink for many years. They bought an Ice Bear electric resurfacer (same idea as a Zamboni). Each wheel has its own drive motor and speed detection bearing. The drivers noticed some jerkiness at times and reported it but nobody considered it a big problem. One day POOF! It died on the ice with a big bunch of sparks and billowing smoke. Turned out the speed detecting bearings went bad and were giving different amounts of current. Eventually the far exceeded the rating of the wiring and fried the entire harness ($60,000 to replace and 9 weeks waiting for one to be made and shipped from Europe). We discovered it has a single slow blow main fuse but no other current protection at all on the motor legs of the harness. Considering the price of one of these things is well over $100k you would have thought they'd spend a few hundred more to protect each motor leg.
  5. I investigated and the problem with Indi is it only supports a few applications. For instance I use stellarium and there's no stellarium support. The nice thing about VirtualHere is it knows nothing about specific devices or software, its just extends USB over ethernet. I just tried VirtualHere with my Canon DSLRs and it just works. BYEOS just thinks its got the camera attached locally.
  6. Switching or linear doesn't mean much, both can be very noisy depending on how well the transformer/switching output is filtered. Switching usually gives more of a square wave while linear is sine - neither is great if the filtering is bad. The good thing is if you think noise is a problem you can toss in your own capacitor to clean it up.
  7. First time I've heard of Indi. I'll have to read up on that!
  8. Has anyone tried mounting a raspberry pi/beaglebone black/whatever running VirtualHere instead of using a remote desktop? Virtualhere works sort of like a USB to Ethernet extender. You run the server on a device that has all the USB devices connected then a client on whatever device you want to use. The client sees the remote USB devices as if they were plugged into the client so you can use your (more powerful) main computer to run all the software rather than using up bandwidth sending the remote desktop and slowing things down using a much less powerful NUC for all the software. I'm going to be trying that sometime in the next couple of weeks (waiting for my scope and LPI-GM to arrive). The only thing I'm not sure about is the 100M ethernet speed from the Pi. It should be fine when imaging/guiding since not of it will be HD live video. Theuncertain part is when using LiveView on my modded T3i for aligning/focusing but considering its a USB2 device and I won't be guiding at the same time, it should be fine.
  9. I've had the skywatcher 12" dob goto for a few years and I've dabbled with tuning up the bearings. I found the first year pointing was nice and accurate but the second year it went south. Adjusting the bearings fixed that up (they were slipping in both axis). I've been dabbling with photography using a DSLR and the results are often quite good with 20-30 second exposures but I keep getting an annoying jump in the altitude axis. What I can't figure out is the exact cause. This mount has two encoders on each axis - one on the motor and one on the scope. When the clutch slips the scope axis and motor encoders mismatch so the controller kicks the motor to try and get them closer together. I figure this is what is causing the jumping. What I'm not certain about is the cause. Do you think it more likely that the bearing is loose, letting the clutch slip or that the bearing is too tight, causing the clutch to slip until the controller gives the motor an extra shot, breaking free of the sticktion?
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