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pete_l

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Everything posted by pete_l

  1. You could take a leaf out of the chinese electronics manufacturing handbook and cover all the wires in hot-melt glue!
  2. Yes, provided a replacement connector was available - or the old one salvageable. It's generally considered bad practice to solder wires directly onto a PCB - no strain relief, for one thing. One probably daft suggestion; have the wires been soldered to the correct positions? In the first photo we can only see some of them Maybe a cracked track from when the OP tried to remove the plug? Or the underlying reason why PBS wanted to remove it in the first place.
  3. Yes, it does. The longer the length of the counterweight bar, the more "whippy" it is. And that leads to greater vibration whenever a tracking correction is made. A shorter bar, even if it the same diameter, will be much stiffer. The stiffness decreases much faster with increasing length than the need for less weigh improves the situation. So it is advantageous to have a short bar with more counterweights than a long bar with fewer.
  4. There are loads of similar products. Widely available in hardware shops or online.
  5. Have you tested the cable for continuity with your multimeter? Failing that, try a different power cable
  6. I reckon that nobody sells kit that works well. Not unless they absolutely have to. What does get sold on is stuff that folk are dissatisfied with, things they want to get rid of to buy something better, or pieces that have a problem (which hopefully the seller is honest enough to declare).
  7. Although it is quite easy to bin the smaller pixels of a modern CMOS sensor to get back to the same sort of resolutions as before.
  8. You got me rather worried about that. So I took my prototype "flip-side" rain detector for a test in the Andalucian sun. I'm glad to say that although it was printed with PLA, it survived the 48° afternoon peak.
  9. The Airy disk is an artifact of diffraction of the incoming photons through an aperture. That has nothing to do with the size of the sensor as the pixels do not cause diffraction. The only time the sensor size becomes an issue is not to do with sampling theory, it is only a factor when compared to the size of the point of focused light (or as we amateur astronomers call it: the "star" ). What optical designers call the spot size. However, even a 1/8 wave optic blurs a star to 4-5 Airy disks [ reference: Schimdt Cassegrain telescope ] - and that is the on-axis spot size! It also takes no account of atmospheric "seeing" that spreads the light out, further. So neither sampling nor diffraction makes any significant difference when applied to real world operations. That is why we still get pretty much rounded-looking stars even with quite large pixels. It is also why star images are spread across many adjacent pixels.
  10. But the camera does not process each photo individually. The other problem is that Nyquist assumes the signal is correlated. Photons are not. At best they are a series of impulses with random arrival times and amplitudes.
  11. Doesn't the Nyquist theorem only apply to continuous signals? It seems to me that imaging produces a discrete result: all the photons gathered in a given time.
  12. You would have to be incredibly unlucky to cause damage removing that - unless the hammer slipped I've just used a photographers blower-brush to knock things like that off a mirror in-situ. Either that or a makeup brush or whatever other soft material you have to hand.
  13. Make sure it can't blow away I use a barbecue cover and that seems to be quite successful. If people have doubt about the efficacy of a cheap cover, why not double wrap your gear? Cover it with two!
  14. Books and articles are full of things that just copy ideas from other books and articles. History books in particular are infamous for perpetuating stuff that has no factual basis. So it would not surprise me if someone simply thought this was true, ages ago, and since then every other writer has just copied it. However, it seems to me that this cannot be true. Since it is always before midnight in as many places as it is after midnight at the same time!
  15. A Raspberry Pi Zero-w with a 12MPix HQ camera using a F1.7 lens in a CS-M12 adapter will give you images like this for a 10 second exposure binned 2x2 For reference, the stars just below Sagitarius' "teapot" are 13° above the horizon according to Stellarium
  16. Got one from this morning (Sun. 08 August) and about 2:30 Spain time. It came from roughly the right direction
  17. At the risk of reopening a dead thread, I have started experimenting with an HQ camera. I use an M12 (12mm diameter screw) lens with a 1.7mm focal length and a M12 to CS adapter. Here's an early example of my playing around from last night at around 1 a.m. (Europe time) so the constellations are in roughly the same alignment as the July images. It is very pleasing to get an all-round horizon with this set up. I'm using the actual same lens (1.7mm f/l) as was in the RPi version 2 camera. The larger sensor on the HQ camera expands the field of view. However, I have yet to find a decent software configuration with my Python script as the HQ camera looks to be less sensitive (i.e. doesn't pick up the faint stars from the V2 camera image). Although this is still a work in progress so I'm not complaining.
  18. I wouldn't put too much stock in that. Sky darkness varies greatly, throughout the night and with the seasons. So if that Bortle 2 was measured estimated in mid-winter, without any tourist facilities open (and their lights on) you may well find that in peak season it is an entirely different situation. I'd say just treat it as a holiday. Relax
  19. Aliexpress has been adding VAT (at least, for my orders in Spain) since July 1
  20. No, plus I don't have any idea which direction it was headed in. The meteor only appeared in one frame. Capella is outside the FoV of my camera at that time of night
  21. That's interesting. I got nothing at that time (03:42 in Spain) but I did get this, at 03:44:33. A couple of minutes later. Just approaching Cygnus, Vega to the right and Altair right and lower. Recorded on a Pi-zero + 8MPix Pi-cam 10 second exposure.
  22. On very rare occasions I have had the vcgencmd process hang with this "broken pipe" state (though it didn't report it as it was run from cron). This resulted in a borked NFS connection from the pi-zero-w that the problem occurred on so it no longer copied images back to the server, A side effect was that the number of processes backed up behind this increased massively (the command ran every 10 seconds) and filled the swap space. I think that is what froze the system and killed the network connection. It only happened twice. The first time I put it down to just one of those things. The second time I investigated and changed my monitoring script from using vcgencmd to get the CPU temperature to looking for the data in /sys (or was it /proc?)/
  23. Testing out sensors for my all sky camera. This first image is from last night (July 15) at around 3 a.m. The camera is a Datyson T7M flashed to be an ASI120M at full resolution 1280x960 with the included wide lens. This second image was from tonight (July 16) at the same time of night. The camera is a Raspberry Pi 8MPix with a 1.7mm lens at 1640x1232 pixels (half resolution) The orientation is rotated 90° (compare the summer triangle in both). Both are 10 second exposures The T7M shows up as much noisier while the Pi camera has what I assume is amp glow across the top 10% of the field as well as in both lower corners.
  24. You might find more information on the German websites
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