[HN Gopher] 1800s Astronomical Drawings vs. NASA Images (2016)
___________________________________________________________________
1800s Astronomical Drawings vs. NASA Images (2016)
Author : dredmorbius
Score : 231 points
Date : 2021-08-18 07:12 UTC (15 hours ago)
(HTM) web link (www.nypl.org)
(TXT) w3m dump (www.nypl.org)
| mrtnmcc wrote:
| > Total Eclipse of the Sun. I personally enjoy Trouvelot's added
| artistic flair (or flare, if you want to be punny) on this one.
|
| The sketch there is actually more accurate than the photo! The
| flare (corona) is real. Cameras have a hard time picking up the
| corona (UV filters?). Here is an example of what it looks like to
| the eye:
|
| https://visitidaho.org/content/uploads/2016/12/Eclipse.png
| mrtnmcc wrote:
| Until seeing that, I never understood why people go through
| such effort to see it from the path of totality strip. It's a
| religious experience.
| xbmcuser wrote:
| Most people do not realise how much light and haze pollution we
| have today compared to 200 years ago. And how visible the stars
| were. Even remote places today are not the same as the atmosphere
| still has more particles compared to 1800s
| sumtechguy wrote:
| I have only had the pleasure to see the milky way once. It was
| in the middle of a loan stretch of road in arkansas. I have not
| seen it since then, 25 years ago. I am the only person in my
| neighborhood who turns off the porch light at night. I want to
| see that again and to share it with others. But alas I do not
| think it will happen :(
| N1H1L wrote:
| When I was a grad student at Penn State, we camped out at
| Cherry Springs and saw the milky way. It was humbling, and I
| recommend it to every person at least once in their life
| pkaye wrote:
| I've seen it at a couple places. One is Lowell observatory in
| Flagstaff AZ. They have pretty good light conditions despite
| being in a city. Second is in certain national parks which
| tend to be away from any big city. Third was on a plane
| flight over the pacific ocean.
| prawn wrote:
| Have you not had the chance in 25 years to go somewhere that
| gave you a decent view of it? Camping or a farmstay?
| sumtechguy wrote:
| overcast and raining...
| prawn wrote:
| For 25 years?
| sumtechguy wrote:
| well yeah... most of the things I like to do are in the
| city. So it just does not come up very often. When it
| did...
| sillyquiet wrote:
| I lived and worked in a small town in the Mojave for close to a
| decade. One of the few perks of living there was the dark sky -
| the milky way for example was eminently visible on most nights
| in a way I think most people never see.
|
| https://www.darksky.org btw
| lanna wrote:
| This picture shows the difference after the city of Dunedin,
| New Zealand, changed all its sodium lights to shielded LEDs:
| https://i.redd.it/hxxp2c3ksdh71.jpg
| zaroth wrote:
| The color temperature of sodium lights is so much better at
| night.
| ericbarrett wrote:
| San Jose used sodium lamps for years in deference to Lick
| Observatory, which is on Mt. Hamilton about 15 miles east
| of the city. The biggest advantage of sodium lights over
| incandescent for astronomy is that the spectral lines are
| very distinct and easy enough to filter out when doing
| scientific studies; incandescent, on the other hand, floods
| the spectrum broadly up to visible light.
|
| I believe LED lamps have similar properties to sodium,
| although I'm not sure how exact they are compared to sodium
| lamps--there might be greater variance in the spectra
| emitted due to material differences; whereas all sodium
| lamps are arcing through a common atomic element and have
| very predictable wavelengths.
| TeMPOraL wrote:
| Also sodium lights don't create so many headache-inducing
| shadow patterns.
|
| For example, a street I walked by regularly for almost
| whole my life recently (in the last few years) got its
| lighting replaced - each sodium lamp is now replaced with a
| LED array with no (or ineffective) diffusor. In other
| words: each spherical source of light got replaced by a
| bunch of point sources.
|
| Last time I walked down that street during night hours, I
| got a vague feeling as if I was playing an old videogame,
| because both the road and the sidewalk looked like a low-
| resolution texture viewed up close: full of smudgy blocks
| that result from texture upscaling. Except those blocks
| moved in a weird dance, making my head spin when I focused
| too much on it, kind of like looking at moving Moire
| patterns.
|
| Turns out, this was the pattern of shadows thrown by leaves
| of a tree, when illuminated by half a dozen point light
| sources.
|
| That's my only complaint, though. LED lights are a win
| overall.
| solarized wrote:
| When the sky still crystal clear to see. The reason why almost
| polymath at that era also mastering astronomy.
| spitfire wrote:
| These remind me of the group of seven artist Lawren Harris. He
| painted Glaciers and nature landscapes in a sort of art-deco
| style. The colour absolutely glows from his paintings.
|
| I get that same feeling here, and I love it.
| blodkorv wrote:
| I wonder what our pictures of space will be seen as in the
| future.
| holoduke wrote:
| Empty. Space is expanding. All matter around us will vanish
| beyond the event horizon. Will take some trillion years through
| perl4ever wrote:
| https://en.wikipedia.org/wiki/Big_Rip
|
| "If the dark energy in the universe increases without limit,
| it could overcome all forces that hold the universe together.
| The key value is the equation of state parameter w, the ratio
| between the dark energy pressure and its energy density. If
| -1 < w < 0, the expansion of the universe tends to
| accelerate, but the dark energy tends to dissipate over time,
| and the Big Rip does not happen."
|
| "According to the latest cosmological data available, the
| uncertainties are still too large to discriminate among the
| three cases w < -1, w = -1, and w > -1."
|
| "In their paper, the authors consider a hypothetical example
| with w = -1.5, H0 = 70 km/s/Mpc, and Om = 0.3, in which case
| the Big Rip would happen approximately 22 billion years from
| the present. In this scenario, galaxies would first be
| separated from each other about 200 million years before the
| Big Rip. About 60 million years before the Big Rip, galaxies
| would begin to disintegrate as gravity becomes too weak to
| hold them together. Planetary systems like the Solar System
| would become gravitationally unbound about three months
| before the Big Rip, and planets would fly off into the
| rapidly expanding universe. In the last minutes, stars and
| planets would be torn apart, and the now-dispersed atoms
| would be destroyed about 10-19 seconds before the end. At the
| time the Big Rip occurs, even spacetime itself would be
| ripped apart and the scale factor would be infinity"
| goohle wrote:
| We have less than 14 billion years before we will fall into
| Great Attractor or Shapley Attractor, or will be erased in
| the process of falling.
|
| https://en.wikipedia.org/wiki/Great_Attractor
|
| https://en.wikipedia.org/wiki/Shapley_Attractor
| dcuthbertson wrote:
| Well, I, for one, don't plan on being there when it
| happens!
| dylan604 wrote:
| Only if we figure out how to get off this one solitary rock
| and expand beyond the solar system. The sun (Sol) will
| continue to go through its natural processes which will see
| it expand larger than the Earth's orbit. That will be the
| end of physical Earth, but life as we know it will have
| ended before then.
|
| So, I'm not sure who the "we" will be that will have less
| than 14 billion years.
| was_a_dev wrote:
| I can't comprehend how some artist manages to draw something like
| a gas cloud so accurately.
|
| In fact it is all impressive, maybe with the exception of Mars.
| _Microft wrote:
| The Orion Nebula [0] is appearing relatively large on the sky,
| about 1deg (= 60 arc minutes) wide. This is approximately twice
| as wide as a full moon appears on the sky. With a telescope,
| you should easily be able to make out details. It's the white-
| ish blob in the "vertical" chain of stars in the lower center
| of this image [1]. The yellow-orange star in the top left is
| Betelgeuse by the way. It was in the news a while ago because
| it had dimmed a lot and some people (not astronomers though)
| were hoping for a supernova. That's a different one from
| "Tabby's Star" which was also in the news because of unexpected
| dimming.
|
| Drawing comes with practice by the way.
|
| [0] https://en.wikipedia.org/wiki/Orion_Nebula
|
| [1]
| https://upload.wikimedia.org/wikipedia/commons/5/5b/Orion_co...
| derbOac wrote:
| Certain elements of the Mars drawing having me looking for an
| explanation. Maybe it's just artistic license, but other
| features are so similar to contemporary photos that it makes me
| think there's a more practical explanation.
| sedan_baklazhan wrote:
| Check out Mars from a decent telescope. It's a blurry tiny
| yellow circle with very unclear "shadows" on it. They drew it
| really well. Much more impressive than Orion in fact.
| darkerside wrote:
| Why is Orion unimpressive? Because the author didn't include
| visible representations of wavelengths that are outside of
| the range of human detectability?
| transportguy wrote:
| the drawing of orion is unimpressive, as it is easily
| visible and drawable to a similar quality with any
| telescope or even binoculars if you have clear skies.
| Spotting any sort of features on mars requires huge
| magnification incredible steadiness and an ability to track
| the object. Drawing the details for Mars required
| magnitudes more ability and far better technology.
| perl4ever wrote:
| For reference, Orion is about 3,600 arcseconds wide
| [http://spider.seds.org/ngc/revngcic.cgi?NGC1976],
| whereas Mars is from 4 to 25 [https://web.archive.org/web
| /20100612092806/http://nssdc.gsfc...] depending on its
| distance.
| rikkipitt wrote:
| Some of the chalk drawings by Lord Rosse et al at Birr Castle in
| the Republic of Ireland are amazing considering they were made in
| the 1840's.
|
| https://birrcastle.com/astronomy/
|
| https://birrcastle.com/telescope-astronomy/
| sedan_baklazhan wrote:
| It is surprising (at least) to see "Book of killed poets" in
| Russian (which is in fact some Soviet era photo paper) as NASA's
| Saturn image.
| malkia wrote:
| Came here to note that, and show off my poor russian language
| skills (bulgarian here) :)
| queuebert wrote:
| Was rotating the NASA images to match the drawings too much to
| ask?
| bjarneh wrote:
| The NASA images of space are colored black and white images, if
| I'm not mistaken. So artists are involved in NASA's images as
| well it seems.
| qayxc wrote:
| You are correct. NASA employs artists to generate published
| press images.
|
| The individual pictures sent by the spacecraft are indeed
| monochrome images taken with different filters. These filters
| don't usually correspond with RGB and calibration is required
| to approximate human perception.
|
| Most of the time there's no equivalent at all (this applies to
| pretty much all deep space imagery) and the colours are
| basically made up (the intensities aren't - they correspond to
| frequency responses, just not necessarily within the human
| vision spectrum).
|
| Here's a discussion on the topic:
| http://ivc.lib.rochester.edu/pretty-pictures-the-use-of-fals...
| TeMPOraL wrote:
| I'm still conflicted. The article you linked goes deep into
| philosophy of knowledge, but still arguably misses the most
| important point - false color can be a tool for analysis,
| pretty pictures are entertaining (and/or good marketing), but
| neither of them let us - individuals - get closer to the
| phenomena.
|
| When I look at photos of distant places on Earth, I do so
| because I'm trying to imagine how would they look like _if I
| was actually there_. This is the main reason people care
| about photos in general[0] - they 're means to capture and
| share an experience. As a non-astronomer, when I'm looking
| for photos of things in space, I also want to know - first
| and foremost - _how would these things look to my own eyes_
| if I was close enough to see them.
|
| The article mentions NASA defending their image manipulation
| as popular astronomy's equivalent of red-eye removal. But
| it's not that. Red-eye removal exists to correct for the
| difference between a flash-equipped camera system and human
| eyes. It's meant to manipulate the image strictly to make it
| closer to what a real human would've seen on the scene. Where
| is astronomy's _actual_ equivalent of that? Pictures
| manipulated in such a way to make them maximally close to
| what an astronaut in a spacesuit would see, if they were
| hanging around the astronomical object in question? That 's
| what I'd like to see.
|
| Such pictures will not be as exciting as the propped up
| marketing shoots, but they'll at least allow the viewers to
| calibrate their understanding of space with reality. I would
| think this would be seen as more important in the truth-
| seeking endeavor of science.
|
| --
|
| [0] - Marketing notwithstanding - the reason imagery is so
| useful in advertising is _because_ of this desire; carefully
| retouched and recomposed pictures are superstimuli, the way
| sugar is for our sense of taste.
| qayxc wrote:
| > [...] what an astronaut in a spacesuit would see, if they
| were hanging around the astronomical object in question?
| That's what I'd like to see.
|
| Well, sorry to disappoint you there but that's technically
| impossible. For most deep space images human eyes would
| likely see nothing at all (because we cannot perceive the
| frequency bands depicted). In other cases it's hard to tell
| because light conditions are vastly different from our
| daily perception (lack of atmosphere, harsh contrasts, very
| little sunlight) and the sensors collected photons for
| hours - something that human eyes just can't do.
|
| One problem is that the equipment used is simply incapable
| of recording images as human eyes would see them - try to
| snap a picture of the evening sky with a smartphone camera
| to see this first hand (unless your newfangled device
| sports AI image enhancement, in which case it's just as
| fake [0]).
|
| > I would think this would be seen as more important in the
| truth-seeking endeavor of science.
|
| Most scientists see this "truth" as something objective
| though, and that's strictly not what human perception is in
| the first place. [0] has a RAW image of a smartphone next
| to an AI's interpretation and that's a good analogy to what
| happens with scientific data as well. Neither of the two
| versions matches what a person would see, yet we accept the
| AI version as being "good", even though it neither is
| depicting what the camera sensor picked up nor showing what
| a person would have seen.
|
| So what is "the truth" in this case? Is it the grainy,
| desaturated and dark raw data from the CCD sensors or the
| artificial construct that tries to mimic what a human
| observer might have perceived?
|
| [0]
| https://www.washingtonpost.com/technology/2018/11/14/your-
| sm...
| perl4ever wrote:
| >For most deep space images human eyes would likely see
| nothing at all
|
| Depending on the definition of "deep".
|
| Presumably in close orbit around a planet, a person would
| see something. In fact, I've read that even on Pluto,
| sunlight at noon is still much brighter than moonlight on
| Earth.
|
| And considering how far away Orion is, what if someone
| was ten times closer? Is it unthinkable that it might be
| comparable to the Milky Way?
| freemint wrote:
| > Where is astronomy's actual equivalent of that?
|
| Removing StarLink satellites? _ducks_
| dredmorbius wrote:
| Most scientific astronomical images are based on capture of
| specific bandwidths and frequencies, which are then assigned
| colours for visual interpretation.
|
| Given that many of the frequencies are beyond the limits of
| human vision (ifra-red, microwave, and radio, at the low end,
| ultraviolet, x-ray, and gamma-ray at the high), this is
| somewhat out of necessity.
|
| The individual channels largely record intensity, so in that
| regard they're similar to B&W photographs, but the intensities
| are of specific bands, rather than a wide range of bands as in
| silver-halide based photographs. There may be some frequency
| variation recorded and interpreted as well, I'm not certain of
| this.
|
| That said, I'm pretty sure that there's also an eye to
| aesthetic and public appeal of landmark released images.
|
| This link shows and discusses multi-spectral images, showing
| the channels individually for several objects:
|
| https://ecuip.lib.uchicago.edu/multiwavelength-astronomy/ast...
|
| The Crab Nebula at frequncies from radio to gamma:
| https://upload.wikimedia.org/wikipedia/commons/thumb/6/6b/Cr...
|
| Galaxy Centaurus-A image which includes infrared and x-ray
| channels: https://apod.nasa.gov/apod/ap210117.html
|
| Today's APOD shows the Ring Nebula in infrared, red, and
| visible light: https://apod.nasa.gov/apod/ap210818.html
|
| You can find such examples by searching for different EMR
| aspects, e.g., "radio, ultraviolet, x-ray". These are typically
| noted in APOD's image descriptions.
| aero-glide2 wrote:
| Nah, many space probes have colour camera too. Here are some
| images from ISRO's Mars Orbiter :
| https://www.isro.gov.in/pslv-c25-mars-orbiter-mission/pictur...
| qayxc wrote:
| These aren't colour images - they're all coloured after the
| fact.
|
| What the sensors do is to take images in multiple
| wavelengths. Each individual channel is still monochrome and
| "real colour"-images are produced by interpreting them as
| red, green and blue with various weights depending on
| calibration.
|
| If you look at the actual sensor wavelengths, you'll notice
| that they don't cover the same frequency spectrum as RGB
| sensors or human eyes. It's all interpretation and
| calibration (that's why the Mars rover have a colour
| calibration plate on them).
|
| Another method (often used with astrophotography) is using a
| single monochrome sensor and put RGB filters in front of it,
| take separate pictures with each filter and recombine them
| (done on Earth).
|
| You can see the frequency bands of the filters used in MERs
| Spirit and Opportunity here:
| https://mars.nasa.gov/mer/gallery/edr_filename_key.html
|
| (the rovers used 16 different filters, so no RGB there)
| _Microft wrote:
| A smartphone camera, DSLR or other camera does not work any
| differently though. It's just that an array of color
| filters is fixed above the sensor's pixels which would also
| be monochrome if it were not there. The readout of these
| pixels is automatically converted to a color image then, or
| stored as RAW for later processing.
|
| This color filter array is called a "Bayer filter".
|
| https://en.wikipedia.org/wiki/Bayer_filter
| qayxc wrote:
| I'd say there's still a difference in that while DSLRs
| and smartphone sensors have individual readouts for each
| colour channel, scientific instruments do not. So a DSLR
| or smartphone camera still outputs a multichannel image
| with a single sensor while scientific instruments are
| strictly monochrome.
|
| They don't take multi-channel pictures in a single shot
| and each full image represents a single channel. HST for
| example has three cameras - one per channel - while the
| MER cameras have a single sensor with multiple filters.
| _Microft wrote:
| From what I know sensors do not have different readouts
| for the different color channels. All pixels are read out
| the same way and, with knowledge of the pattern of the
| Bayer filter in use, are then processed ("de-mosaiced")
| into a color image.
|
| If one removed the Bayer filter from a sensor (as
| difficult as that is) and skipped demosaicing while
| processing the image, one would end up with a monochrome
| image just fine. Using physical color filters for
| different channels and taking the same scene for each of
| them, one could create a single color image with even
| better resolution than the camera normally would. Why
| better? - this might disappoint you now! - consumer
| cameras count each differently colored 'sub'pixel as a
| full pixel. So half of the "megapixels" of your camera
| are e.g. green and just a quarter of them each red and
| blue (that's a common ratio for the colors). The camera
| then 'fakes' having a full set of RGB pixels by
| demosaicing, see
| https://en.wikipedia.org/wiki/Demosaicing ). Taking
| monochrome image with physical color filters would allow
| to use the full resolution of the camera for each color
| channel.
| qayxc wrote:
| That's exactly what I wrote, though.
|
| > From what I know sensors do not have different readouts
| for the different color channels.
|
| You know wrong then. HST uses three camera sensors
| precisely to have three different filters at the same
| time and at full resolution:
| https://www.stsci.edu/hst/instrumentation/legacy/wfpc2
|
| So yes, the WF/PC2 does indeed have different readouts
| per channels because each channel has its own dedicated
| sensor.
|
| Maybe you simply misinterpreted what I wrote. The fact of
| the matter is that consumer level sensors return multi-
| channel images (the sub-pixel filtering is an irrelevant
| technical detail), while scientific instruments use
| dedicated sensors per channel.
|
| edit: just to clarify even further - there are no
| subpixel shenanigans with scientific instruments for both
| higher precision and to avoid cross-talk between
| frequency bands; hence separate sensors per frequency
| filter. if you want multiple channels at once (e.g. space
| telescopes), you therefore need multiple sensors as
| opposed subpixel filtering.
| _Microft wrote:
| OK, I think I understand the confusion now. I understood
| "readout" as hardware implementation detail (think:
| "readout circuit") while it seems to refer to the data of
| a particular channel, right? My lack of familiarity with
| the lingo seems to blame then.
|
| That "subpixel shenanigans" on scientific apparatuses are
| inacceptable should be understood.
| tigershark wrote:
| What you are saying doesn't make much sense. It's obvious
| that the images are taken on different wave lengths and
| recombined. Cameras with a Bayer filter use exactly the
| same principle but have worse spatial resolution because
| they have micro-filters on each pixel and the result is
| interpolated. Foveon sensors work in the same way with
| different layers sensible to a specific wave length. Even
| our eyes work in the same way with the rods and cones that
| are sensible to luminance and different wavelengths. By
| your definition what we see are not colour images since
| they are processed after the fact by our brain from the
| separate wave length signals coming from the receptors in
| our eyes.
| qayxc wrote:
| You misinterpreted what I wrote then.
|
| Yes, a consumer-level camera sensor uses Bayer filtering,
| but that's just an implementation detail just like the
| rods and cones inside the retina - you don't perceive
| each channel individually after all, lest you wouldn't be
| able to perceive "brown" or "pink".
|
| So any analogy between CCD sensor output and human eyes
| ends right there.
|
| The difference lies in the output of the sensory
| mechanism (be that human eyes or CCD sensors). While
| consumer level hardware outputs multichannel images (yes,
| by means of subpixels and Bayer filtering, but that's
| irrelevant - for the sake of argument it could as well be
| pixies), scientific instruments use separate CCD sensors
| for each recorded channel to a) keep the full resolution
| and b) avoid cross-talk between different frequency bands
| , which is unavoidable with the subpixel setup used in
| commodity hardware.
|
| So while your smartphone or DSLR's RAW output will be a
| multichannel image, instruments onboard of spacecraft
| will only ever output a single channel per sensor. No
| subpixels, no Bayer filters. Either one dedicated sensor
| per recorded channel (e.g. HST WF/PC2 camera) or multiple
| images taken in series using a single sensor but multiple
| filters (e.g. cameras onboard MER and MSL rovers).
|
| I hope that was a little clearer.
| fulafel wrote:
| I'd argue if you have sensors that take images in
| multiple wavelengths, and they are combined, it amounts
| to a imaging system (=camera) that senses colors - vs
| upthread argument of "colored black and white images".
| qayxc wrote:
| The issue is that the multi-wavelength combined image
| doesn't correspond to RGB like the RAW output of DSLR or
| smartphone camera.
|
| The different bands received from spacecraft, rovers and
| (space-)telescopes are matched with red, green and blue,
| even though they're actually taken in near infrared, UV,
| or even X-ray spectra.
|
| The "truth" is that the images are only monochrome
| representations of recorded photons of different
| energies. Most people don't see near UV light for example
| and some images are taken in very narrow bands and then
| "stretched" into "full" RGB, etc.
|
| The point is that the recorded data doesn't correspond to
| the human vision apparatus (or at least not well) an thus
| any multi-colour representations are necessarily
| fabricated and sometimes don't even try to reflect what a
| human would have seen.
| tigershark wrote:
| The Foveon sensor that I mentioned before works exactly
| in the same way getting 3 full resolution images at
| different wave lengths, exactly like the scientific
| cameras. And I'd argue that the only difference between
| this approach and the eye/Bayer sensor is the resolution,
| the underlying mechanism is exactly the same.
| qayxc wrote:
| But does the Foveon sensor use RGB filters or does it
| work with different frequency bands? That's a major issue
| with science data - it doesn't contain RGB data for the
| most part, because that's not what scientists are
| interested in.
|
| What's the correct colour channel to use for for near UV
| (yes, I know that some people - mainly women - can
| perceive that, but the vast majority of people can't)?
| What matches near IR or even X-rays? How would you
| colourise the frequency bands that match different
| elements (those include very narrow bandpass filters) but
| don't really make sense in terms of RGB?
|
| That's the difference right there. If you have a picture
| that uses channels of different filter bands that
| correspond to hydrogen bands, organic molecules or UV
| radiation, none of that data correlates to human colour
| perception. So someone just chose shades of green for
| hydrogen or shades of blue for organics.
|
| So what I'm trying to say is that the underlying
| mechanism is irrelevant - the data simply isn't colour
| data as seen by humans.
| dredmorbius wrote:
| What captivates me about the drawings is the range in detail and
| accuracy. Keep in mind that naked-eye observations are difficult,
| limited to the colour sensitivities of the human eye, and often
| are working at or near the limits of perception --- the fanciful
| details on Mars are extrapolation of a very small blurry rusty
| dot.
|
| The detail of the sunspot images is exquisite.
|
| The other aspect is that until the advent of photography, _all_
| image preservation was mediated by the human eye, mind, and
| artistic ability, and often the 2nd or further-removed hand
| accounts and relating of original events or objects. (See
| Albrecht Durer 's rinocerous for one of my favourite examples of
| this.) The century or so from the mid-19th through mid-20th
| century where direct analogue impressions of images, sound, and
| movement were possible gave us a period of robustly reliable
| records (within the limits of equipment, and still subject to
| manipulation). The age of computer-modified and -generated
| imagery once again leaves us with high-fidelity images which may
| have remote, little, or no bearing on any actual reality. This
| includes, for what it's worth, many of the NASA images provided,
| which are more data interpretations than realistic
| representations of astronomical objects.
| narag wrote:
| I also thought that wasn't "fair" since many of the comparison
| images are taken with long exposure times.
|
| I have a very old astronomy book that includes similar drawings
| of Jupiter and they're much more detailed and realistic.
| dredmorbius wrote:
| Where "long" may be measured in anything from hours to
| months.
|
| The Hubble Ultra Deep Field image (a follow-up to the
| original 1995 Deep Field image of an "empty" region of sky),
| has a total exposure time of just under 1 million seconds (11
| days), with single channel exposures of a minimum of about
| 1.5 days.
|
| This somewhat exceeds the duration and light-collecting
| capabilities of a human observer.
|
| https://en.wikipedia.org/wiki/Hubble_Ultra-Deep_Field
|
| Though granted, such prolonged exposures aren't necessary for
| the nearer observations (many within the solar system)
| included in the article here.
| redisman wrote:
| Especially the Orion Nebula. I see the picture on the left
| and think oh yeah that's almost exactly what I see with my
| scope. Then on the right it's some crazy photoshopped
| (playing with channels) long exposure.
| tusslewake wrote:
| Curious, what is the book?
| narag wrote:
| "Astronomia" in Spanish, by Jose Comas Sola. It was a gift
| for me, almost 50 years ago. I think it was a little dated
| already.
| sandworm101 wrote:
| >> and artistic ability
|
| Don't forget the physical limitations of the medium. Want to
| paint a nebula as it fades from white to the black of space?
| Try to paint a gradient between two colors, a steady blend from
| white to black across a few inches. It is the sort of thing
| even the great masters never attempted because it is basically
| impossible.
|
| These images were not meant to be exact representations. These
| are anatomy diagrams. They allow the reader to understand and
| recognize the objects rather than be mirror images. We have
| photographs, but doctors still learn from hand-drawn diagrams.
| wumms wrote:
| What happened to NASA's Saturn?
| sirfz wrote:
| Click on the link under the picture to view the intended photo.
| I'm still interested how this error happened tho
| red_trumpet wrote:
| Also it's the same as the teaser photo at the beginning of
| the article.
|
| Edit: Could also be that the photos on the server changed.
| After all the article is 5 years old.
| sedan_baklazhan wrote:
| It became a vintage Soviet photopaper with a weird name.
| matoyce wrote:
| The 1800s astronomical drawings are very detailed and accurate. I
| do wonder how beautiful are the night skies in the last 100-200
| years. Today's light pollution made it hard for us to appreciate
| the beauty of the night sky.
| stunt wrote:
| Everything about early astronomical drawings is astonishing. Even
| when you go way back in time when they had no telescope, they
| were still able to map out visible stars pretty accurate.
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