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| Sagittarius A* |
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| aetherist:
--- Quote from: dunkemhigh on May 15, 2022, 01:42:20 pm --- --- Quote ---Now, here we have a problem. The signal has to go from the detector to the counter-recorder. Via wires probly. Are the wires insulated? What length of wire is needed? What effect duz temperature (of the Cu)(& of the insulation) have on the speed of electricity on the wire? --- End quote --- Isn't that why you calibrate stuff? So you can determine that kind of offset and allow for it? --- End quote --- Yes i suppose that u can calibrate for lots of factors. But consider a large array of dishes. If each dish is identical to the others, & if each one has its own counter-recorder then u don’t have to worry about the length of wires (eg wires going to a central control room with the counter-recorder). But u still have the problem of the temp being different in different dishes. And, u also have the problem of having to synchronise the clock in each dish. Or, if all of the dishes in the array are wired to a central counter-recorder (with a central clock) then u don’t have to worry about synchronising lots of clocks, but u do have to worry about different lengths of very long wires (which can be calibrated ok), but that calibration will not be able to handle any temp differences of the wires (temp affects the speed of electricity on the wires). So, even if waves & wavefronts existed (which they don’t), & even of plane wavefronts existed (which they don’t), & even if the nearness of the mass of the Earth did not affect the plane of the wavefront (which it duz), & even if the atmosphere did not affect the plane wavefront (which it duz), then the problem of the varying speed of the signal along wires to the counter-recorder (due to temp diff) would be an impossible problem. Bearing in mind that they are looking at 1.3 mm long waves (i think), hence a difference of 1.3 mm in the speed of electricity in the wire (due to a diff of temp) would represent a full wavelength, & i am guessing that their image (for that array) is messed up if the diff is merely a very small fraction of 1.3 mm. |
| aetherist:
--- Quote from: TimFox on May 15, 2022, 02:14:23 pm ---Another lecture from a meeting in 2015: https://www.eso.org/sci/meetings/2015/eris2015/L6_Heald_calibration.pdf Those seriously concerned with this interesting engineering problem should consult the references contained therein. --- End quote --- In my previous reply i mentioned the problem of the speed of electricity on a wire due to temperature. In other threads on this forum i have advised that the speed of electricity along a wire will be affected by the aetherwind, which blows south to north through Earth at 500 km/s (which is c/600). The horizontal component of the aetherwind at some locations on Earth can vary from say 140 km/s to 480 km/s during a sidereal day. That’s a difference of 340 km/s (ie c/882). Depending on the alignment of any wiring on a dish that 340 km/s might be a headwind or a tailwind or a crosswind (for the electricity), all of which affect the speed of electricity along the wire. If the length of wire is 1 m then a diff of c/882 will show as in effect a diff of 1/882 in the length of the wire during the course of a day (here i mean that the wire might seem longer or shorter based on the time for electricity to propagate along the wire), & this 1/882 is 1.13 mm, which is almost one full wavelength (1.3 mm). Do the horizon team calibrate for the aetherwind? Nope. However, the aetherwind would not be a big factor if each dish in an array had its own clock-counter-recorder, koz they would all be affected in equal measure. But if there were long wires connecting to a central clock-counter-recorder then the aetherwind would be fatal. More potential problems re the changing aetherwind during each 24 hrs, & during each orbit of the Moon, & during each orbit of the Sun. The lengths of wires contract or dilate, which will change the time taken for electricity to propagate along a wire. And dishes change shape. And atomic clocks change their rate. |
| PlainName:
--- Quote ---But consider a large array of dishes --- End quote --- I encourage you to check out the document Tim linked to. |
| aetherist:
--- Quote from: dunkemhigh on May 15, 2022, 02:55:57 pm --- --- Quote ---But consider a large array of dishes --- End quote --- I encourage you to check out the document Tim linked to. --- End quote --- I didnt see any calibration for aetherwind. At least not by name. |
| PlainName:
One only needs to calibrate for things that exist. |
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