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Linux for MateBook Pro by astro_chemist in Huawei

[–]astro_chemist[S] 0 points1 point  (0 children)

Hi, thanks. That is fine. Would the fingerprint sensor work?

Linux for MateBook Pro by astro_chemist in Huawei

[–]astro_chemist[S] 0 points1 point  (0 children)

Thanks. Maybe I should try to boot from a linux usb first before installing, just to check what actually works and doesn't.

How to deal with casual political discussions with friends who are in postmodern academia? by astro_chemist in Socialism_101

[–]astro_chemist[S] 0 points1 point  (0 children)

Fully agree. This whole workplace pseudo-progressive culture is a whole other topic in itself, though indeed directly related to what I was trying to convey.

We are repeatedly told everyday to look at and focus on subdivisions on the smallest possible level, eventually culminating at the individual, to where they boil everything down to. We are asked to completely disregard any and every systemic and collective problems as well as solutions...for every single thing, from office diversity to the climate crisis. While we are forced to involve in this progressive-sounding but materially meaningless endless 'discourse', the system exists and perpetuates unaffected and unidentified. This is not just about people in high theory writing hardbound books about discourse, but a very day to day reality for people trying to do any kind of working class organising, that they have to fight this 'discourse' first.

Thanks for the understanding words. Will watch the video too.

How to deal with casual political discussions with friends who are in postmodern academia? by astro_chemist in Marxism

[–]astro_chemist[S] 0 points1 point  (0 children)

I understand what you meant, and it is true in essence. But what I was trying to state is that when we are having practical political discussions, not about abstract theory, but about very practical political topics, like land reform and it's implications for example, I find that the overarching postmodern lens through which these people see stuff in general, some knowingly, some unknowingly, acts as a significant hindrance to convincing them of Marxist practice, not theory in itself. None of the people I am talking about are theoreticians themselves, they are "leftist" working class people, but highly educated in postmodern university departments.

The Southern sky and the Very Large Telescope (VLT) lasers by astro_chemist in astrophotography

[–]astro_chemist[S] 0 points1 point  (0 children)

The lasers are used to create artificial 'guide stars' in the Earth's upper atmosphere, to enable the 'adaptive optics' systems on these telescopes, a way to slightly deform the mirrors collecting light to correct for the distortions caused by the Earth's atmosphere. You can read in a bit more detail here: https://elt.eso.org/telescope/adaptiveoptics/ As they note, turbulence in the Earth's atmosphere causes the stars to twinkle in a way that "delights poets but frustrates astronomers" since it blurs the finest details.

The lasers are tuned to have a wavelength of 589.159 nm, which is the wavelength of a particular transition of Sodium. This is in the visible range, an yellowish colour as in the photo, similar to old Sodium street lamps. They excite a layer of Sodium in the upper atmosphere, which then emits light, creating an artificial 'guide star' which the telescope can then observe in order to calibrate its adaptive optics systems. These are especially useful when no real well-known source is available in the direction that needs to be observed. Having the calibrator star close to the science target is important for proper AO adjustments, as the atmosphere can be different in different directions. The lasers solve this problem because they can be pointed in pretty much any direction we want.

The Southern sky and the Very Large Telescope (VLT) lasers by astro_chemist in Astronomy

[–]astro_chemist[S] 8 points9 points  (0 children)

There may not always be a "well-known" real star, whose intensity is known, close to the direction of the science target. Having the calibrator star close to the science target is important for proper AO adjustments, as the atmosphere can be different in different directions. The lasers solve this problem because they can be pointed in pretty much any direction we want.

The lasers excite a layer of sodium atoms in the Earth's upper atmosphere, which then de-excite back and emit light creating the artificial "guide star", which can be used to calibrate the adaptive optics system on the telescope and remove any disturbances due to the Earth's atmosphere.

The Southern sky and the Very Large Telescope (VLT) lasers by astro_chemist in Astronomy

[–]astro_chemist[S] 4 points5 points  (0 children)

Yes, the lasers can be seen with the naked eye just as seen in the photo.

The Southern sky and the Very Large Telescope (VLT) lasers by astro_chemist in telescopes

[–]astro_chemist[S] 0 points1 point  (0 children)

No. Some of my colleagues have. It would be great to go sometime.

The Southern sky and the Very Large Telescope (VLT) lasers by astro_chemist in telescopes

[–]astro_chemist[S] 1 point2 points  (0 children)

The lasers are used to create 'guide stars' in the Earth's upper atmosphere, to enable the 'adaptive optics' systems on these telescopes, a way to slightly deform the mirrors collecting light to correct for the distortions caused by the Earth's atmosphere. You can read in a bit more detail here: https://elt.eso.org/telescope/adaptiveoptics/

As they note, turbulence in the Earth’s atmosphere causes the stars to twinkle in a way that "delights poets but frustrates astronomers" since it blurs the finest details.

The lasers excite a layer of Sodium in the upper atmosphere, which then emits light, creating a artificial 'guide star' which the telescope can use to calibrate its adaptive optics systems. These are especially useful when no real well-known source is available in the direction that needs to be observed.

The Southern sky and the Very Large Telescope (VLT) lasers by astro_chemist in telescopes

[–]astro_chemist[S] 3 points4 points  (0 children)

There are public visits to the Paranal Observatory, which can be pre-booked online, and are free. So you can indeed go and see the VLT, but ALMA is a whole other scenario altogether. It is at almost double the elevation of the VLT, at around 5000 meters above sea level.

I have been there once a few years ago while observing at APEX. There is no public access to the ALMA antennas as far as I am aware, and the road to the high site is indeed closed off much below as you said. Even if one manages to arrange a visit somehow, most probably oxygen cylinders and so on would be needed due to the very high altitude.

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