petschge

28 ms·

271.
Boing 737-800 at Istanbul overran runway, impacted wall, broke up(avherald.com)
18 points by petschge 7y ago|4 comments
272.
by petschge 7y ago
And if you install by the usual method of "just keep pressing enter" you opt out of popcon. You have to make an effort to enable it.
273.
by petschge 7y ago
The Xe is supposed to power Aurora, the next big DOE supercomputer.
274.
by petschge 7y ago
You can derive hydrodynamical (and magnetohydrodynamical) equations in a rigorous (as opposed to empirical) way. BUT that gets you an infinite hierarchy of equations where the equation for the density contains the flows, the equations for t
275.
by petschge 7y ago
This is not a bad question (turbulent transport is very important for magnetic confinement fusion), but the answer is unfortunately "very little". This work considered only hydrodynamics, which does not describe the inclusion of m
276.
by petschge 7y ago
Getting insurance can be done online in about 5 minutes and the registration at the DMV equivalent is your problem (as the buyer) afterwards and can be done anytime in the next 2 weeks.
277.
by petschge 7y ago
Within the EU movement if fairly unrestricted and does not require anything that you listed. Go check http://www.europarl.europa.eu/factsheets/en/sheet/147/free-m...
278.
by petschge 7y ago
That was a decade ago and I don't remember. My main point was: Yes it is good to have a standard implementation that comes shipped with C++, but that does not mean you can not do better for your special case. And it might be possible w
279.
by petschge 7y ago
While your probably will not write something better than std::vector in a good c++ library such as libc++, it is quite possible to do better than a bad implementation of std::vector. Source: I have done better than the std::vector that was
280.
by petschge 7y ago
Ah, yes. The famous American pharma companies Roche, Novartis, Bayer, GlaxoSmithKline and Sanofil come to mind...
281.
by petschge 7y ago
An increasing number of papers in my field have the DOI the cited paper as a hyperlink to dx.doi.org which will redirect to the publisher website. Note that this is often done without optical hints (text in black not blue, no underline) so
282.
by petschge 7y ago
> At the same time, I don't know anyone working in aviation who thinks it's 100% a coincidence that the first crashes happened with those two airlines. There are always multiple factors in play. I don't know much about Lio
283.
by petschge 7y ago
Given the long queues at the sticker boxes and their general popularity: yes.
284.
by petschge 7y ago
Sure. But increasing the number of frames with tracks increased the number of datapoints you need to throw away, reducing the effective time on target and therefore sensitivity of your observations. Astronomers are not idiots. They know how
285.
by petschge 7y ago
What useful thing has been produced by the internet? I'd much rather have humans enjoy nature than writing about it on the internet.
286.
by petschge 7y ago
A very large fraction. Optical is still the most important band, probably followed by radio, x-ray, IR and gamma ray in that order. And less then 10% of optical is done using satellites.
287.
by petschge 7y ago
The dead of night will be fine. But during (astronomical) twilight, the time when you are most likely awake and looking up, it will have ugly extra dots.
288.
by petschge 7y ago
It is very clean ice, with is shielded by another 1.5 km of ice on top and that is filled with more than 5000 photomultipliers.
289.
by petschge 7y ago
You also need a minimum thickness and stability if you ever want to turn the mirror to point elsewhere.
290.
by petschge 7y ago
For radio we might be able to make it work. But we currently don't have the ability to position satellites to within 10 nanometers, which would be required to make this work in the optical range that you have just killed off on the gro
291.
by petschge 7y ago
During twilight our section of EVERY frame would be ruined. Massively reducing the useful observation time during twilight. And keep in might that some sources are only visible to some telescopes during those hours. And we have neither the
292.
by petschge 7y ago
> Uncharitably, you might say HN has a ton of Dunning-Kruger about anything not directly technology related. It's even worse. It is people thinking that because they are brilliant in some technical field (JS frameworks, or compilers
293.
by petschge 7y ago
Astronomical sensors typically are 12 bit. So anything 4000 times brighter will overflow the sensor and can not be subtracted. And of course you have perfect solutions to Poisson noise, bleeding pixels, and increased dead time caused by sho
294.
by petschge 7y ago
Yeah it is interesting that people are more willing to sacrifice the night sky then exert political pressure to get the horrible internet situation in the US fixed. Also interesting how people who could not find the big dipper think that re
295.
by petschge 7y ago
> It seems possible to launch multiple small telescopes and operate them as one large scope using aperture synthesis. I don't know if there are any existing designs or plans for this. We know how to do that in radio (VLBI), have som
296.
by petschge 7y ago
See https://doi.org/10.1117/1.2031216 for the scaling of cost with size. It is very much not linear. Rather if you double the diameter the cost goes up by about a factor of 3.5 (closer to the area that went up by 4).
297.
by petschge 7y ago
Photons are not individually time tagged (that is much harder and reduces quantum efficiency due to dead times), but rather are collected for some exposure time (think 30 seconds) and then their count is read.
298.
by petschge 7y ago
The Cherenkov emission is boosted in the direction of travel, i.e. downward. And there are too many lights on the surface of the Earth.
299.
by petschge 7y ago
On traditional telescope using photomultipliers such as Magic, Hess or Veritas: no. But systems with solid state detectors such as FACT are moving in that direction.
300.
by petschge 7y ago
There will be many more than typical satellites, so it is only fair to require "much dimmer than usual".

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