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pete_l

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About pete_l

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    Brown Dwarf

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    http://www.under-a-dark-sky.com

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  • Location
    Benamaurel, Spain 37N
  1. One big question is what do you intend to do with this?. Is it to perform a simple task such as checking whether the sky is cloudy or clear. Or do you want to do more advanced work, such as meteor detection. A clear/cloudy sensor doesn't need to be any more complex than a webcam and a cheap fixed-focus fisheye. You aren't aiming for "photo" quality images - just looking to see if there are (any) stars. Their colour, position or pin-pointedness is not important. The window the camera looks through doesn't need to be anything special, either. For the next step up, which is to identify constellations and produce movies of movement through the night you will need a better lens and an improved cover for the camera. If you are intending to mount it high-up a method of keeping that cover clean - free from dust deposited by rain. However, if your location is surrounded by trees and houses, it is unlikely that a lens providing a horizon-horizon view is needed. Remember, you can point the camera at an angle, away from close buildings. Much the same applies to meteor detection. Although since they are fast-moving, long exposures aren't needed but a sensitive camera is. As is a low F-number lens. In general, remember that an enclosure that starts off waterproof may not continue to be after repeated cycles of sun and frost/snow. Or if the unit provides a convenient perch for birds, accumulations of dust may be the least of your worries.
  2. I think anyone expecting deliveries from China (or indirectly from suppliers who only drop-ship orders from Chinese suppliers) will be in for long delays. Some countries have stopped accepting parcels and letters for China as there are so few flights still operating to there. I've got a couple of Aliexpress orders that have been stuck "Awaiting shipment" since the end of January.
  3. Not so. The counterweight bar acts as a lever and the counterweight itself is the force that provides that leverage to balance the telescope. Therefore the forces acting on the bearings inside the mount are the same. It is not the weight that matters, but the forces. In addition a weight closer in to the centre can be "spun" faster with the same effort that it takes to move a smaller weight further out. Hence having your counterweights closer in means the mount will respond faster to changes in the driving motors.
  4. I think the paperwork you need is an ATA carnet (pronounced: car-nay). We used to use them to send equipment out of the UK for demos, exhibitions and the like. They work on the basis that the kit will be returned to the UK and that it is only going "overseas" temporarily. You may also need to have proof of ownership: the receipt or credit card record.
  5. I would suggest having a look at what these people are doing. It will give an idea of the sorts of results that can be obtained. https://www.meteornews.net/2018/12/16/the-2018-geminids-from-croatia-with-raspberry-pi-meteor-systems/
  6. Yes, just seem Mercury. 20 minutes ago with the image stabilised Nikons. Just now, when its darker, visually. Though with the 25°C we had today ..... winter?
  7. Don't post too many. At 64MPix and 16 bit depth for a mono frame, I doubt the server has enough storage space for lots of raw images.
  8. I gave up on relays for this reason among others (such as not trusting the "optimistic" power ratings). Have you considered solid state relays such as this? There are also heftier versions for power switching, though they are recommemnded for use with a heat sink. Best reason: no moving parts!
  9. An easy thing to (dis)prove. Take a 30s exposure. If the image is delivered directly after the exposure finishes, no dark frame was subtracted. If you have to wait another 30s, you can deduce that it did subtract a dark. Of course, this presumes that the camera did take a true 30s exposure, not a 15s one followed by a 15s dark. But again that is easy to verify by comparing a 30s exposure from the same chip in another manufacturer's camera with the ASI one. I think I can sniff a bovine, here.
  10. The "industry standard" for glossy magazines is 300dpi (pixels per inch). Your camera will be about 3300 x 2500. So in theory, if you were publishing for Vogue or somesuch, then no. However in practice it will be fine. The reason is that the larger a print (or screen), the further away people view it from. So the 300dpi rule isn't really anything more than a historical fiction for people who revel in searching out imperfections, rather than enjoying the big picture (literally ). For example, a 27 inch (diagonal) monitor is a little less than 600mm wide. A 1920x1080 image viewed at a normal distance is perfectly acceptable. Even though it is only 3.2 pixels per millimetre or 80 DPI.
  11. This scale? The numbers look fine to me. Personally, I'd say that there is a huge "acceptable" arcsec/pixel range for most situations. You can get great photos anywhere from <0.5 arcsec to 5+ arcsec. Just look on Astrobin and you will see all sorts of numbers and some excellent end results. Since you already have the equipment, the ultimate test is to set it up and try it out.
  12. I have a SS2K with my GPDX (still going strong). The battery only powers the internal memory when the unit is switched off. If you are not losing your settings between sessions, then the battery is fine. The SS2K does suffer from issues with the thick cable from the hand controller. Sometimes one of the wires will become frayed or break entirely. The symptoms you describe could be caused by an intermittent connection there. The control of the motors comes directly from the hand controller, which could explain the jittery motion. That is where I would look first. After that a close inspection of the power cables and connections.
  13. USB connectors are only designed for indoor use. As are the cheap "network" style connectors to the guider / handset. I would suggest the first thing to look at would be ALL these connectors. Not just the ones on the cables, but the ones on the equipment: computer, mount, handset as well. Even being gold plated, they are still prone to corrosion, accumulation of dirt and simple wear and tear. It is also doubtful that cheap connectors would have gold plating to anything more than the absolute bare minimum. Just enough to outlive whatever warrant they came with.
  14. pete_l

    USB leads

    I would suggest getting the right cable without adding adapters. You can get pretty much any combination of length, connector and orientation from Aliexpress. Although with the Chinese new year coming in a couple of days, it's best to order soon, or wait until Feb. If you are concerned about quality issues, I fully expect that any UK supplier gets their product from the same/similar source. Unless they fabricate each one themselves.
  15. If a product is skillfully marketed, a higher price on its own is viewed by many customers as a real advantage Terms such as "premium" or "for the serious user" imbue an air of exclusivity in their own right.
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