
Hubble captures vivid auroras in Jupiter’s atmosphere - fforflo
http://www.spacetelescope.org/news/heic1613/
======
Isamu
Note: the dramatic photo is a composite, of Jupiter in visible light and its
auroras captured in UV.

~~~
readams
Nearly every photo of space you see, especially from Hubble, is usually a
composite, falsely colored, or otherwise altered in ways that bring out the
important features of the photo. Note that the idea of "true color" for these
sorts of astronomical photos is itself a bit ill-defined.

Here's some information about the kinds of manipulations that might go into
these photos:
[http://hubblesite.org/gallery/behind_the_pictures/meaning_of...](http://hubblesite.org/gallery/behind_the_pictures/meaning_of_color/)

~~~
Kenji
>Note that the idea of "true color" for these sorts of astronomical photos is
itself a bit ill-defined.

Why? Because of Relativistic Doppler Effect?

~~~
dakr
Astronomical cameras don't capture color information in the sense that our
eyes or consumer digital cameras do. They are "black and white" only
detectors. To get color information, several images are taken with different
filters in front of the detector. Afterwards, those images can be stacked and
each layer assigned a color to create a composite image.

Making this a "true color" image that exactly mimics what your naked eye would
see ranges from difficult to impossible (like in the case of UV data). It's
also unimportant, because we mostly use color images as a visual aide (of
course!). The "science" is in comparing and contrasting the individual "color"
images.

~~~
steve19
This is exactly how CMOS/CCD image sensors (used in digital cameras) work [0].
Each "sub-pixel" is just a photocell which detects light intensity. A bayers
filter on top of the sensor array filters light colors so different "sub-
pixels" detect colors (light intensity of different parts of the visual
spectrum) [1]

Enthusiasts sometimes remove the filter to get higher optical resolution or
better contrast B&W images. You can even buy consumer cameras with this
feature off the shelf [2]

NASA is doing the equivalent of instagram filters, making photos appear more
appealing to the general public. NASA says (via. Space.com [3]):

"Creating color images out of the original black-and-white exposures is equal
parts art and science," NASA said.

For example, Hubble photographed the Cat's Eye Nebula through three narrow
wavelengths of red light that correspond to radiation from hydrogen atoms,
oxygen atoms, and nitrogen ions (nitrogen atoms with one electron removed). In
that case, they assigned red, blue and green colors to the filters and
combined them to highlight the subtle differences. In real life, those
wavelengths of light would be hard to distinguish for humans."

In other words, ignore the colors.

[0]
[https://en.wikipedia.org/wiki/Image_sensor](https://en.wikipedia.org/wiki/Image_sensor)

[1]
[https://en.wikipedia.org/wiki/Bayer_filter](https://en.wikipedia.org/wiki/Bayer_filter)

[2]
[https://en.wikipedia.org/wiki/Leica_M_Monochrom](https://en.wikipedia.org/wiki/Leica_M_Monochrom)

[3] [http://www.space.com/8059-truth-photos-hubble-space-
telescop...](http://www.space.com/8059-truth-photos-hubble-space-telescope-
sees.html)

~~~
privong
> In other words, ignore the colors.

I'm not sure exactly what you mean by "ignore". The colors, though somewhat
arbitrarily chosen, do convey physical information. It may not be a "what your
eye might see" image, but it does tell the viewer about the relative emission
from hydrogen, oxygen, and singly-ionized nitrogen (for the Cat's Eye Nebula).
So, the coloring isn't something that could be ignored.

One way to describe those types of images is "representative color".

~~~
steve19
"Cat's Eye Nebula ... In real life, those wavelengths of light would be hard
to distinguish for humans."

The context of the my comment was how the photo compare to the naked eye.

I used to take IR photos for fun (consumer camera with IR filter replaced with
visible light filter), and used thermal and night vision technology at my job.
They all relay useful information, but are not photo-realistic in anyway.

An IR photo of Earth for example, useful but not photorealistic.

[http://bobqat.com/Essays/disteyes/color-
ir.jpg](http://bobqat.com/Essays/disteyes/color-ir.jpg)

I imagine the Cat's Eye just looks like a bright cloud :)

~~~
privong
> The context of the my comment was how the photo compare to the naked eye.

I agree that is true for your example of the Cat's Eye nebulae. I guess my
response was to my (and presumably other's possible) mis-interpretation that
"ignore the color" was aimed at color astronomy images in general.

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fapjacks
I am _so_ happy HST's mission was extended for another few years [0]! I would
have funded a Kickstarter to keep it going, to be honest. If there's one thing
Hubble does well, it's that it capture the hearts and minds of muggles like
myself. HST is an amazing piece of machinery.

[0] [http://www.nasa.gov/press-release/nasa-extends-hubble-
space-...](http://www.nasa.gov/press-release/nasa-extends-hubble-space-
telescope-science-operations-contract/)

~~~
jessriedel
That would have to be some kickstarter :) The operating costs of Hubble are
about $100M/year.

~~~
amock
According to the linked press release it will cost less than $200 million for
an additional five years, so the cost is less than $40 million/year.

~~~
jessriedel
I read elsewhere it cost $98M/yr recently, so it might be that this extension
isnt maintaining the full capabilities.

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donkeyd
The timelapse is pretty cool!
[http://www.spacetelescope.org/videos/heic1613a/](http://www.spacetelescope.org/videos/heic1613a/)

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dkelly2020
Would you have been able to see these auroras with the naked eye?

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stuaxo
Looking forward to seeing this reposted on new age forums, as "Hubble Captures
Jupiters Aura".

