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randomic

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Everything posted by randomic

  1. On topic: Nice try, telescope thief! But seriously I have displaced a wardrobe of my fiancée's clothes and it is now my astro gear cupboard.
  2. The whole glass being a very slow flowing liquid thing is a myth. You don't have to worry about your lenses. https://www.cmog.org/article/does-glass-flow
  3. The EdgeHD 800 is amazing for planets. On a good night I can make out details on Mars and can see the disk and colour of Uranus, it's awesome. I use the Baader Zoom 8-24mm eyepiece. For imaging planets I have a ZWO ASI 462MC but I've not been able to take it for a spin yet due to weather. You technically can do it with a DSLR but what you really want is high framerate video capture. For galaxies, the EdgeHD 800 is again pretty great for visual. I use the 40mm eyepiece which comes with the OTA and can make out the core of Andromeda even from very light polluted skies. Your experiences here
  4. I almost bought that combo but the general consensus is you can get better mounts for the same money. So, I bought the EdgeHD 8" OTA and HEQ5 Pro separately. CEM25p is a good alternative. An 8" SCT OTA is on the limit of what these mounts can perform well with for long exposures so you might want to stretch for a Celestron CGX or CEM40 mount. Alternatively you might get an autoguiding setup to help the mount perform at its best. I've really enjoyed my EdgeHD 800 so far but it might be just as good getting a C8 XLT, unless you know for sure that you want the internal flattener (which
  5. If I had to spend that much I'd probably go with iOptron CEM40 and a Celestron EdgeHD 925 but it depends a LOT on what kind of targets you want to shoot. BUT If you're just starting out I don't think you need to spend that much. A SkyWatcher HEQ5 Pro or iOptron CEM25p paired with an 80mm apo like SkyWatcher Evostar 80ED will net you some amazing shots of wide field targets.
  6. Just seen this thread, maybe it's the same for you?
  7. Yes, however tides in gasses tend to be dominated by heating effects so you don't notice the gravitational atmospheric tide so much. It's still a contributor though.
  8. I made a diagram which might help visualise. These points are not interacting so in the right-hand case they would drift apart indefinitely. Obviously, the oceans are gravitationally bound to the Earth so they don't just leave The red ellipses are not supposed to be an accurate representation of the tidal bulge shape, rather just a visual aid. P.S. The end of the caption on the right hand diagram should say "the outer two move away from it."
  9. Hypothetically, couldn't everything happen on the gpu? Since as long as the frames end up in the right order it doesn't matter in what order they're processed (assuming you don't run out of vram).
  10. Hot damn, I'd better make sure I crop the frame!
  11. Out of boredom I built oacapture from source this afternoon and you'll be pleased to know that the ASI462MC is now recognised correctly. It seems to work fine although only manages to record at 6 fps. On a semi-related note, is a 67 frame SER supposed to be ~500MB?
  12. Yep, the bulge is caused by the non-uniform gravitational field across the Earth. We see the bulge in the oceans because the Earth is (relatively) rigid and water is not. Check my posts in this thread for more information.
  13. It shouldn't be too hard to run the numbers. We'll keep things Newtonian for simplicity. So a = GM/r^2 G is Gravitational constant 6.67e-11 Radius of Earth, re, is 6,371km Mass of Sun is 2e30 kg Distance to Sun from Earth centre, rs, is 149,785,000km (going off the above diagram) Mass of Moon is 7.3e22 kg Distance to Moon from Earth centre rm, is 384,835km a at Earth centre due to Sun = 6.67e-11 x 2e30 / (1.5e11 + 0)^2 = 0.0059289 m/s^2 a at Earth close edge due to Sun = 6.67e-11 x 2e30 / (1.5e11 - 6.371e6)^2 = 0.0059294 m/s^2 The difference between these two is the tidal
  14. As a side note: counterintuitively, this means that you not only weigh less when the moon is directly overhead but also when the moon is directly underneath.
  15. The key part which is being missed is that it's the non-uniformity in the field which is important. If we imagine the Earth as a rigid sphere then: the water closest to the Moon "feels" a stronger acceleration towards the Moon than the Earth does the Earth "feels" a stronger acceleration towards the Moon than the water furthest from the Moon does the net result is that you get a tidal bulge at each side. It's got nothing to do with the springiness of water or pressure or anything like that. You see tidal forces in action in merging galaxies, where stars are (effective
  16. astroberry@astroberry:~ $ lsusb Bus 002 Device 002: ID 03c3:462b Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 2109:3431 VIA Labs, Inc. Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub astroberry@astroberry:~ $ lsusb -vs 2:2 Bus 002 Device 002: ID 03c3:462b Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 3.00 bDeviceClass 0 bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 9 idVendor 0x03c3 idProduct 0x462b
  17. It's not quite happy with sdk version v1.15.0915 for whatever reason. Here's the log output: astroberry@astroberry:~ $ LD_LIBRARY_PATH=/usr/lib/arm-linux-gnueabihf oacapture libEGL warning: DRI2: failed to authenticate qt5ct: using qt5ct plugin qt5ct: D-Bus global menu: no Unrecognised camera '' open of camera 0 failed Happy to do any further testing if it's useful to you.
  18. Got a Raspberry Pi 4 and the lockup issue seems to not happen anymore. There is some weirdness about data acquisition rates though: if I set a target fps of 20 I get roughly 20, any faster and it starts wildly oscillating, averaging between 10 and 2. (In kstars) Additionally, dmesg gets spammed with messages about the usb device getting "reset". From what I understand, this is normal with ZWO cameras when changing configuration but not during capture. Hoping this is just teething troubles with the drivers/sdk, it is certainly useable now. I'll keep updating this thread with any new i
  19. Amazing! Thanks so much! Is it built into the binary or is there a directory I can drop the new so to test it out locally?
  20. I just looked at the default nginx config for astroberry and it listens on all port 80, so it shouldn't matter at all from where you're connecting. There is some other problem. Are you able to load the astroberry webpage? Is it just the desktop (VNC) bit which isn't working?
  21. I don't know what causes this but I have seen it in other photos. For example: Although in Olly's picture it appears to have some radial symmetry around the field edges. I've also seen a similar thing appearing as well as the diffraction spikes from Newtonian vanes but I can't find an example right now. What do defocussed stars look like? Maybe there's a clue in there.
  22. You read my mind! I was trying to decide on the RAM. I think I might go for the 4GB version anyway just for futureproofing. Very excited for 10s platesolves, it can easily take 2 minutes+ for me at the moment.
  23. Aand the lock up happened almost straight away. So I think this rules out power as the issue.
  24. I was about to reply saying that, unfortunately, I don't have a way to rule out power to hand. But then an epiphany. My PC monitor has a powered USB hub built in. It only has USB 3 slots so I can't rule out some weird USB 2 problem but I'll give it a shot.
  25. I tried with the Pi1 and although the poor hardware couldn't really keep up with the demands, it didn't lock up in the same way the 3B does. I guess this must be something to do with the hardware. I'll update the original post to specifically reference the Pi 3B Looks like I'm ordering a Pi4 sooner than anticipated!
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