See also Articles 7 and 8 of the Charter of Fundamental Rights of the European Union (https://www.europarl.europa.eu/charter/pdf/text_en.pdf). (side note, the ECHR is why European countries have strong privacy laws since the '70s.)
In principle, yes. In practice, no. National security is a matter of the member states. Note that the right to privacy is also in the Dutch constitution. From the little I know, the oversight mechanism in the Netherlands seems to be working to some extent but there are still plenty of caveats:
DB is not privatized, it is 100% state-owned. As far as I know, all ICE power cars are still in use today, except for the one destroyed in the Eschede accident.
Spiegel Online found out that (for some reason) parts of the text are visible in the bookmarks of the PDF if it is right after a section heading. This includes the redacted text.
I just checked the twitter account of the first author (who does not seem to be currently affiliated with any scientific institution). I can only understand his German and English tweets. He likes to push his own book, retweeted a post claiming "just stop testing for the virus and people will die of influenza again", and calls other peoples work pseudoscience.
Why don't you talk about the 10 points that the scientists state to argue that the test is flawed? And what do you have to say about the other 21 scientists? What do you have to say about the former Pfizer chief scientist which is co-author?
That former Pfizer guy apparently claimed in October that the coronavirus pandemic is “effectively over” in the United Kingdom. Clearly a man with special insights.
I have experience only with the Very Large Telescope run by ESO in Chile, maybe what I write is only valid there.
There is usually no real schedule of targets for ground-based telescopes.
There are two ways chosen at the telescope: either the astronomer who wrote the application is sitting there and decides what to do, or the staff goes through a list of approved programs and looks for objects that can be observed. This depends on the constraints described in the program (usually atmospheric conditions and height of object above horizon). Which target is chosen next is usually decided during the observation of the last target, there is no real schedule.
This is of course different for robotic telescopes (which is absolutely not the standard), like the Hubble Space Telescope but also ground-based robotic telescopes. But I'm not aware of a live feed of the pointing coordinates for them.
What one could do is regularly query the ESO archive[1] as finished observations appear there immediately (I think) and contain coordinates (just enter night: "2020 01 01" and maybe chose type: object).
In case of the Hubble Space Telescope and also ESO's telescopes, you write a proposal containing the science case, the requested time and instruments, and related previous experience, submit it before a deadline (twice each year for ESO) and hope for the best. The acceptance rate for the HST is currently ~20% [2]. It's a bit better for ESO telescopes. If you are successful you do not have to pay anything. ESO even pays your flight and hotel next to the telescopes in the middle of a desert [3].
The situation is totally different for American telescopes (as far as I know), where you either belong to an institution that has telescope time or not.
We have photometric all-sky surveys that can map the entire sky (visible from the telescope location) during a night up to a certain brightness. But those only take images of the sky, not spectra (Zwicky Transient Facility and the planned Vera C. Rubin Observatory).
What we also have are integral-field spectrographs which can take 2D images with a twist: there is one image for every ~0.1nm from 480nm to 950nm. You take one exposure with the instrument and you get a stack of thousands of images. If you go through the stack at a fixed spatial position you get the spectrum.
The problem is that the integral-field spectrograph with the largest field-of-view is already huge (it is called MUSE at is located at the Very Large Telescope). And its field-of-view is "only" 1 arcmin^2 (1 deg = 60 arcmin), which is by far too small for large surveys. If you wanted to image the whole sky each night with MUSE clones, you would need several millions of them.
A single MUSE exposure is about ~5 GB in the end but there are intermediate data products which are about 10 GB, if I remember correctly.
I gotta say I'm quite jealous of your dark skies and beautiful photography.
Also, how are you overcoming flexure and mirror flop with your setup!? I have troubles keeping a 6" stable for a minute with a reasonable mount. Do you have more info on your setup anywhere?
I see this question a lot. I used to have an obsession with 'true color'; images felt fake otherwise. Artificial.
I'm a working scientist now, and my view has changed. I realize how limited our senses are. How much of the world--of the universe--I'd miss by restricting it to just what my eyes can see natively. Even among colors that I can see, but perhaps the signal is too faint ... I'm a lot more tolerant of color-mapped images now. I don't see them as artificial anymore, but as beautiful and transcendental. A window into a hyper-spectral world normally invisible to me. It's really something special. I wish I could share this perspective with more people.
Alex Grey studied cadavers at Harvard for years. His art tries to show the true medium, not one limited by visible light. Sort of like what Superman might see. Our bodies are emanating light in a spectrum of frequencies (Planks law.) All this light is leaving our bodies at C, whiles all the light from the universe is coming at us, our "light cone." We see the surface of bodies..but the actual substance of reality has interfering rippling waves emanating and being absorbed..not unlike a pool. So the next time someone tells you someone is ugly, remember that the visible light surface is just the beginning..
The artist of drawings for Scientific American for many years made his drawings super-real by emphasizing components of interest. And these were black-and-white.
I think the beauty is lost on me when I don't know what the color means. I either want the real deal or to know what the mapping is so I can appreciate that. Otherwise it's just a pretty picture.
Agreed! This is important. Scale bars would be nice too, as well as info on other pre-/post-processing. Usually all this is in an associated publication (which is hopefully freely available), since it usually takes a surprising amount of information to fully understand an image like this.
> beauty is lost on me
> pretty picture
Pick one ;) Sometimes we can find things beautiful without fully understanding them (arguably this is always the case). For me, knowing whether it’s derived from real measurements is what matters. But everyone’s threshold is different. I’ve seen beautiful simulated data too, but that’s something different again — more like the beauty of an equation to me.
I think it boils down to two things (at least it does for me):
- If the picture is shown as if it was a photo, how similar is it to what I'd see if I were magically transported in a spacesuit into object's vicinity?
- If the picture is an obvious false-color render, does it have a reasonable color map, or some "artist's impression"?
It's a real eye-opener when you realize that our eyes are no more "true color" than a CCD... I didn't really get that until I took a graduate optical observing class.
The advantage of MUSE is that you get all color information, i. e. the flux at any wavelength from blue to red.
In principle, one can use this together with the sensitivity curve for our eyes to construct a natural image.
In this case, I think, they tried to imitate the color scheme from the Hubble image which is more limited.
In short: Not sure how realistic this is, but one could make a realistic image from the new data.
Exactly! One datacube that comes out from the instrument contains 300 x 300 spectra. This is actually the main capability of the instrument which has 24 individual spectrographs.
Here's a nice animation of the path the light takes inside MUSE: https://www.youtube.com/watch?v=-fh2Y6Zyhwc&feature=youtu.be...
Could one use that information the other way around to make estimates for expected "missing data" in Hubble images taken in areas where VLT has not looked yet, for example to decide where to look next?
<something something throw machine learning at it cliché>
Not sure if you meant it like this but redshift estimation comes to my mind. The farther away a galaxy is, the redder it becomes. You can measure the distance (redshift) from galaxy spectra (with MUSE for example) but not from directly HST images.
This mapping color -> redshift is called photo-z and was tested with MUSE data in an very famous area observed with HST, the Hubble Ultra Deep field. https://arxiv.org/abs/1710.05062
> With this new capability, the 8-metre UT4 reaches the theoretical limit of image sharpness and is no longer limited by atmospheric blur.
Theoretical limit as in diffraction limited? How will this technology "scale" to other frequencies and resolutions? Related to this diffraction limit: is there any overlap in the advances in microscopy and astronomy? For example, do advances in super-resolution microscopy[0] affect advances in optics in astronomy? Could advances in adaptive optics in astronomy somehow translate to microscopy?
(I'm also curious if this technology will make putting telescopes in satellites not worth the cost, but that question was already asked and answered here: https://hackertimes.com/item?id=17557482)
Yes, the diffraction limit is meant here. The VLT has four 8 m mirrors, for each of them the angular resolution limit is = wavelength/diameter = 8 * 10^(-8) rad.
The practical resolution of the new narrow-field mode is about 4*10^(-7) rad, and it was one order of magnitude larger before.
Adaptive optics is the key invention here. As far as I know, it works better in the near-infrared than in the red part of the optical range, and it gets worse toward the blue part. Due to this, our resolution changes as a function of the wavenlength, since MUSE captures the flux from all wavelengths at the same time.
It's funny that your mention super-resolution microscopy because Stefan Hell, one of the Nobel Prize winners for advances in that field, works in the same city as we do. So far, I don't think we have any overlap with what he does.
> It's funny that your mention super-resolution microscopy because Stefan Hell, one of the Nobel Prize winners for advances in that field, works in the same city as we do. So far, I don't think we have any overlap with what he does.
Why not arrange a kind of meet-up? :) Surely exchanging ideas would lead to interesting ideas, and in the worst case you can at least by inspired by geeking out over mega- and micro-optics together.
In my first year of grad school (1995) our microscopy professor showed us an astronomy adaptive optics paper and said "we're going to do that". Years later, they did that.
We can achieve a very high resolution from the ground but only in a very small field of view. To cover one typical HST image with MUSE at the VLT, we would need a mosaic of hundreds of exposures.
The reason for this are the four artificial guiding stars from the lasers. The closer they are together on the sky, the more atmospheric distortion you can correct.
Some parts of the electromagnetic spectrum are also not possible to observe from the ground. That's mainly UV and shorter wavelengths (X-ray, gamma-rays). We will always need space telescopes if we want to have these photons.
Actually what I was looking at was the field of view of an individual MAMA detector in the Space Telescope Imaging Spectrograph, that instrument has about ~ 100 x 100 arcsec2 of total field of view apparently.
Yes. You need one dot for each patch, where the distortion inside each patch is approximately constant inside a single instant. Now, handling these multiple dots in a good way, that's another story. Compare the patch size/discussion in https://publikationen.uni-tuebingen.de/xmlui/handle/10900/49...
This is very much unexplored territory, but ESO thinks so.
The ELT (https://www.eso.org/public/teles-instr/elt/) will use more lasers but the exact configuration is still work in progress, as far as I know.
Adaptive optics is really only effective in the infrared. And really only in the near-infrared, as past 5 microns, we can't really see through the atmosphere. In the visible, ground-based can't match space observatories (in the visible, the atmospheric turbulence is way harder to correct for).
> In the visible, ground-based can't match space observatories (in the visible, the atmospheric turbulence is way harder to correct for).
The image this article is about is mostly in the optical (MUSE only goes from 465nm to 930nm; and the synthetic filters used in the MUSE image [4] seem to be quite close to the used HST filters).
> And really only in the near-infrared, as past 5 microns, we can't really see through the atmosphere.
Not quite true [1] (at least if only considering absorption), it's just that the background becomes more and more of a problem (both continuum and narrow emission lines), and one has less nicely defined windows of transmission and lots of strongly variable absorption lines (picking dry places for the telescopes and selecting nights with low water vapour column densities helps). At the VLT for example there is VISIR [2], which does mid-IR imaging and spectroscopy.
Of course the sensitivty from the ground is much lower than from space or somewhere in between (for example there is SOFIA [3] which is a 2.5m telescope on an airplance) and some bands of interest are indeed absorbed.
But there are indeed projects that involve mid-IR observations that can be done from the ground.
Ah my bad, I mean that in the visible, you can't reach the diffraction limit with AO like you can in the near infrared. Certainly impressive matching HST from the ground.
I don't think past 5 microns there's been a lot of science done from the ground (not counting SOFIA). Practically, I think everyone is waiting for JWST. A lot of the interesting molecular lines also get absorbed by the Earth's atmosphere.
In those pictures of neptune, what is the KM-per-pixel were looking at?
Is there a minimum focal length on this? Purely hypothetical: Could we basically see astronaut's footprints on the moon with this? What about looking into the window of the ISS?
In this narrow-field mode of MUSE, the CCD detector can resolve 0.025 arcseconds per pixel (arcsecond is a weird unit for angles used in astronomy). At the current distance to Neptune (according to wolframalpha: about 30 au = 4.5 bn km), this corresponds to about 500 km/px.
Due to observing conditions, I think the real resolution was more like 0.07...0.08 arcseconds, so maybe it was 1000 to 2000 km/px.
I'm not sure if the focal length plays any role here. The resolution is usually limited by the telescope size (true for all telescopes, scales with 1/diameter) and atmospheric conditions (only relevant for ground based ones). At the distance of the moon (300,000 km), the physical resolution is 36 m/px and for the ISS (400 km) it is 5 cm/px.
If you want to play around with it, here's the formula:
length_still_resolved = angular_resolution * distance
The angular resolution is 1.2 * 10^-7 (= 0.025 arcseconds converted to radian), distance and length_still_resolved have the same units.
> Q: Could the VLT take a picture of the Moon-landing sites?
> A: Yes, but the images would not be detailed enough to show the equipment left behind by the astronauts. Using its adaptive optics system, the VLT has already taken one of the sharpest ever images of the lunar surface as seen from Earth: http://www.eso.org/public/news/eso0222/. However, the smallest details visible in this image are still about one hundred metres on the surface of the Moon, while the parts of the lunar modules which are left on the Moon are less than 10 metres in size. A telescope 200 metres in diameter would be needed to show them. [continued]
Can you tell us about your favourite globular clusters? I know some of them have very interesting properties like having similar stellar ages but are there any really peculiar ones you can tell us about? Also, I'd love to see some of the images your referring to.
I like NGC 3201 because we found a stellar mass black hole in it (https://www.eso.org/public/news/eso1802/). There should be many more of them in all clusters, but they are hard to find. Theorists can use this to check their N-body simulations of globular clusters.
Some clusters (omega Cen, 47 Tuc) are really weird and different from all others. We think that they might be the remnant cores of dwarf galaxies.
Not sure it's exactly what you're looking for, but I really liked:
- The Making of Prince of Persia - Jordan Mechner
- Masters of Doom - David Kushner.
- Founders at Work - Jessica Livingston (aggregate of stories)
Pretty cool in different ways:
- The first shows how the author documented a good chunk of the process (like solving the problem of the Prince's alter ego).
- The second by the journalistic work the author went through and access he had.
- The third by the context it gives on many things (for example, you get a glimpse on Palantir's current work by looking into Paypal's history and the work Max Levchin, CTO at the time, and his team did on fraud detection, or Hotmail's growth tactics).
