welterde

27 ms·

301.
by welterde 6y ago
Until recently there was no real alternative to it though. I recently learned about waypipe, so it should be possible to run wayland applications remotely over SSH at last (not sure how well it works/performs, but it exists). Granted t
302.
by welterde 6y ago
> Nobody is, nor was, sending the equivalent of a ground telescope installation upwell. You only send the looking part, with a downlink bolted on them. You do control and data processing planetside. That rack full of electronics is the l
303.
by welterde 6y ago
JWST still hasn't be launched yet. And space observatories are much much more expensive than ground-based ones. JWST for instance will cost around 10 billion dollars in the end - and they don't even have to pay for the launch cost
304.
by welterde 6y ago
You are forgetting that the telescope has to work in space. Big thermal swings, no easy air cooling, no AC outlet to get your power from, no convenient anchoring point for your telescope to push against to point a certain direction, no just
305.
by welterde 6y ago
If no light falls onto the detector then there is no blooming. And of course there will be diffraction from the shutter edges as well, so engineering it will be quite a challenge (one can take hints from coronographs). If the satellites doe
306.
by welterde 6y ago
If the conditions are quite stable that might work (or if one can live with limited accuracy), but conditions tend to change over time (moon position, thin clouds and of course the seeing - how much the atmosphere distorts the image) so not
307.
by welterde 6y ago
Shutters for astronomical instruments are specifically designed to open and close evenly, so that each pixel of the detector receives the same amount of exposure time (as good as is possible). Otherwise it becomes very difficult to calibrat
308.
by welterde 6y ago
Sure. And for small field of view things that might be the future. But if you are looking at large chunks of the sky at some point with enough satellites the shutter will have to stay shut for the whole duration of the exposure.. so not rea
309.
by welterde 6y ago
The readout time for astronomy CCDs is typically between 2 and 30s (going faster produces more noise), so there is a lower limit on how short you can make exposures. In LEO the apparent movement of satellites is around 3.6 arcmin per second
310.
by welterde 6y ago
CCDs are not really receivers that can be turned off for a couple seconds. A physical shutter moves in front of the detector and covers it (for most instruments as they exist right now).
311.
by welterde 6y ago
Like I said interferometers exist but they are very limited in their capabilities. For example the VLT interferometer is limited to observing objects that are brighter than 18th magnitude (and that's using multiple 8m telescopes! Using
312.
by welterde 6y ago
The two donated telescopes were the same diameter as the one Hubble had, but were designed to cover a larger field of view (since the small FoV of Hubble wouldn't have been very useful for reconnaissance). But they came without any ins
313.
by welterde 6y ago
No. That's not how optics works. The resolution is set by the diffraction limit of the optics, which is mostly limited by the diameter of the aperture. This is not something you can magic away (I am aware that interferometers exist, bu
314.
by welterde 6y ago
What kind of equipment are we talking here? First thing that comes to mind are lithography machines, but for the very high-end ASML is the only game in town currently afaik. And they are sitting in the Netherlands (working with Zeiss in Ger
315.
by welterde 6y ago
The planned capacity is however only 4400 people per hour for the CES tunnel so about 14s spacing (some other projects even lower). One train every 90s has a capacity of more than 10000 people (and that's not even rush hour with any pe
316.
by welterde 6y ago
NX partially solves the problem that applications don't use the X primitives anymore and are way to chatty with the X server (which leads to many unnecessary roundtrips which is the real killer for remote X11). Old applications work gr
317.
by welterde 6y ago
There is no way you can get even close to the same capacity as a subway.. not even for a point to point setup. Minimum train space with pretty standard signaling can be as low as 90s. With modern moving block systems that can be pushed even
318.
by welterde 6y ago
Didn't it already have Iridium on board as well? I read some claims that the power bus was unstable and thus it shut down the satellite radio multiple times before it could transmit much meaningful data. Which would imply that Starlink
319.
by welterde 6y ago
Fiber optic cables have a much much higher usable bandwidth than the wireless spectrum. The useful radio spectrum for Starlink is somewhere between 10 and 20 GHz. Fiber optic cables have more than 4THz of usable spectrum. And it's no a
320.
by welterde 6y ago
If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.
321.
by welterde 6y ago
Ipython/jupyter notebooks fill that niche quite nicely.
322.
by welterde 6y ago
python+pandas [1] is probably quite an easy choice for most common things people would use excel for. And being in the python ecosystem offers lots of libraries for statistics, machine learning, signal analysis, plotting etc. [1] https:&#x
323.
by welterde 6y ago
We are not talking about just a few games as in the pre-steam days, but ~30% of all games on steam have native ports for linux now and over 70% can be played with proton by now. And in the end you will always have to make a choice what game
324.
by welterde 6y ago
The rest of the world can do the same just fine with Celsius? And didn't really answer my question either..
325.
by welterde 6y ago
The numbers are not fantasy at all - this will be a huge radio telescope - one square kilometer of pure collecting area and thousands of receiving antennas (For reference: Arecibo has around 0.073 km^2). We are talking data input to the cor
326.
by welterde 6y ago
It still gets processed though and only all non-interesting events get discarded.. Otherwise the tape alone to store it on would exceed their total operating budget in a day, so they have to be a bit clever about it.
327.
by welterde 6y ago
The argument for using SI is simply that you are a) using the same units as everyone else b) using a set of units that connect neatly together so one can actually do meaningful calculations with them. And °C is not part of SI either, but is
328.
by welterde 6y ago
I don't agree that is quite strong. He starts with a number of purely subjective requirements that make Fahrenheit look good and ignores all other use cases. Such as centering the zero around the freezing point of water is quite useful
329.
by welterde 6y ago
On the other hand as of ~3 months ago it wasn't enough to show all the typical covid-19 symptoms to be allowed to get tested at all (in the Stockholm region at least). They have since expanded testing, so in principle anyone can get te
330.
by welterde 6y ago
IPv6 can do that too though! 6in4 is exactly equivalent to the proposed EIP extension. EIP still splits the internet into the old legacy v4 internet and the new EIP internet that cannot communicate with the old internet, since while you can

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