Hubble Releases First Post-Upgrade Images

Hynee writes "As tweeted, NASA has released 10 new images, all from the new WFC3 instrument and others, including the Cosmic Origins Spectrograph. Images include NGC 6302, Carina Nebula, Stephan's Quintet, Markarian 817, Abell 370, and a few others. Great looking stuff, the WFC3 has twice the resolution of the WF/PC2, on the CCD at least, if memory serves correctly. Eta Carina is a fascinating object, and there are at least two releases in this 'Early Release Observations' set." Here is a video about the new images at Hubblesite.org, and a full HubbleSite.org release page with 56 images.

Re:Colors in photographs

[eldavojohn]

I bet we've got a really smart person out there that knows the answer for this, for sure. I asked my professor and they really danced around and didn't give a straight answer (it was a community college). What about these brilliant colors we always see in the photographs? Are they touched up (I've read and NASA insists, "no, they're not")? Are they extrapolations based on the inferred composition of the gases in a nebula, for example? Or is it honest to goodness, if we were parked in a space ship a few million miles away, exactly what our eyes would register?

Your answer is on the FAQ in one of the linked sites here [hubblesite.org]:

There are no "natural color" cameras aboard the Hubble and never have been. The optical cameras on board have all been digital CCD cameras, which take images as grayscale pixels.

Sometimes the color is as natural as possible. However, the color given to the images is not just "artistic embellishment." The images are, indeed, downloaded as black and white, and color is added for a number of different reasons -- for example, to show the dispersion detail of chemical elements and highlight features so subdued that the human eye cannot see them.

For more information, read The Meaning of Color [hubblesite.org] on HubbleSite, which explains in detail how color is added to images.

Re:Colors in photographs

[A beautiful mind]

Red shift and the properties of visible light travelling means that you indeed see "false colour" images, but there are no "real" colours to speak of on the other hand. If you would park your space ship a few million miles then the picture would look entirely different, not just in the colours.

False colour in this case is about visualizing non-visible frequencies of light.

Re:Colors in photographs

[fuzzyfuzzyfungus]

Depends on the image, I think. Many(possibly most or all) are false color. With output from instruments beyond the puny human visual spectrum, you don't even have much of a choice. You take one or more wavelengths and on some mixture of arbitrary and aesthetic grounds, assign them to visible colors, with the intensity of the visible color at a given pixel set by the intensity of the other wavelength for that given pixel.

Re:Colors in photographs

[Anonymous Coward]

That depends on the image, the camera, and the technology.
If the image isn't true-color, your eyes will see something different. False-color images have non-visible frequencies mapped onto the visible spectrum, and might not be showing anything in the visible spectrum at all. True-color will be pretty close, but read on.
Then there's the camera. Cameras don't reproduce the visible spectrum exactly. Some are more sensitive in the near-infrared, some can show you near-UV. In both cases, the image will tend to be color-shifted/compressed towards blue or red, to various extents.
Then there's exposition, focus, depth of field, optical filters, etc. These generally won't have much of an effect on color, but could make things more or less blurred, produce lens effects, render dim objects visible, etc.

Re:Colors in photographs

[Zocalo]

There's an example of the Carina Nebula showing both "false colour" and something a closer to the "real colour" you would see from your space ship at The Register [theregister.co.uk]. It's also one of the images from the 56 at the Hubble site linked in the story, but let's try and spread the Slashdotting Love around...

Also, your "few million miles" just might be a little off and in some cases a few million light years or more would be more realistic. :) Some of these dust clouds and so on are *BIG*. If the Tarantula Nebula [wikipedia.org], for instance, was located as close as the Orion Nebula [wikipedia.org] it would cover about a quarter of the sky.

MAST Mirror Site

[eldavojohn]

thanks guys, posting this and now the hubble site is slashdotted!!! so now nobody gets to see the images until some other story (Britney Spears enrolls into MIT?) vectors the crowd away so us commoners can see hubble pictures.

I'm seeing the official NASA images just fine but MAST (Multimission Archive at STScI) put up an early mirror here [stsci.edu] if you need the full size images. These are only the press release images, I'm going to keep watching MAST for the full set but you have ftp info for these now here:

ftp archive.stsci.edu
logon as anonymous
cd /pub/sm4earlydata

Archive.org runs a really neat NASA images site [nasaimages.org] that allows you to pick your favorites and make presentations or new montages with them. I'm not seeing the new images up on that yet but they will probably have them up soon.

Re:MAST Mirror Site

[Zocalo]

Also NASA's Weekly Top 10 page [nasa.gov] is worth a look. It'll take a week or maybe two for the cream of the latst Hubble pictures to filter to the top though; updates are every Tuesday night or Wednesday morning depending on your timezone.

Re:Colors in photographs

[camperdave]

Because all digital cameras are greyscale. It is simply a matter of which filters are placed in front of which pixels. So your question becomes "why don't we have filters to mimic what the eye naturally sees?", and the answer to that is that (A) they can get better science out of the filters they have, and (B) If they use a particular set of filters they can mathematically generate what the eye sees, so there's really no need. The Hubble isn't a coin op sightseeing telescope, it is a precision scientific instrument.

Re:Would like to see the improvement

[eldavojohn]

If anyone finds a link to side-by-side images from the old and new cameras, please post it!

I'll give it a shot. (note: on some of these I'm using MAST's archive since the main NASA site seems to be down [stsci.edu] and I am not linking you to full resolution photos as well as seeming to be at different ranges)

Old (2007) Image of NGC 6302 [nasa.gov] compare with new image of NGC 6302 [stsci.edu]
Old (2004 not HST, ground observatory can't find HST image) Image of NGC 6217 [stsci.edu] compare with new image of NGC 6217 [stsci.edu]
Old (2007) Image of Carina Nebula [nasa.gov] compare with new image of Carina Nebula [stsci.edu]
Old (1998 land observatory) [nasa.gov] Images (2000 HST) [nasa.gov] of Stephen's Quintet compare with new image of Stephen's Quintet [stsci.edu]
Old (2008) Omega Centauri [yimg.com] compare with new Omega Centauri [stsci.edu]
Old (2005) Supernova Remnant LMC N132D [nasa.gov] compare with new Supernova Remnant LMC N132D [hubblesite.org]

Hopefully that gives you an idea, most of those old images are Hubble but I threw in some ground based observatory ones so that you can get an idea of what Hubble's been doing for us for 15 years.

Re:Colors in photographs

[Dachannien]

Indeed, and for those folks wondering how the digital camera works that they have at home, see http://en.wikipedia.org/wiki/Bayer_filter [wikipedia.org].

fsck twitter

[tedgyz]

I don't give a flying fsck that NASA tweeted! Just give me the goddam info!

C'mon geeks - do you want to share ranks with Chris Coumo [twitter.com] of Good Morning America [go.com]?

I am the anti-twitter.

Re:Bayer filters

[bay43270]

That's different. An infrared camera has the ir filter removed and an additional filter added to block non-ir light (see the video here http://www.lifepixel.com/ [lifepixel.com]). The old filter blocked ir light across the entire sensor. It's essentially like any other filter you would put on your lens. A Bayer filter is completely different. It filters each individual cell of the sensor with one of three colors. Each cell knows which color was used to filter it. It would have to be implemented on the sensor itself.

Re:Colors in photographs

[Bill of Death]

Because, when using a color filter array, you throw away 2/3 of your light. Plus it's inflexible.

Re:Colors in photographs

[node 3]

The filters you are talking about are affixed to the CCD/CMOS. The filters on Hubble are interchangeable (more similar to lens filters on SLR and similar cameras). The cameras on Hubble have dozens of filters to choose from.

The other benefit is that on a standard 3 color CCD, you end up combining four pixels to create one full color pixel. With Hubble, you get to use all four pixels independently because they all share the same filter.

Comparison Photos

[Anonymous Coward]

Here ya go

http://www.universetoday.com/2009/09/09/just-how-good-is-the-new-hubble-lets-compare/

Re:Colors in photographs

[E-Lad]

As already mentioned, the Bayer filter is part of the CMOS sensor itself. It's not a separate part that's tacked on near the end of the manufacturing process.

There is, however, a separate filter in front of the sensor on pretty much every DSLR. This is a IR cut-off filter. Naked CMOS sensors are very sensitive into the IR spectrum. This high-pass IR filter prevents deep red and IR from overwhelming the resulting image, producing a balanced red against the green and blue end of the visible spectrum.

There are several cases where one would want to modify their DSLR and have this filter removed. The primary users of this method are astrophotographers who wish to use a much cheaper DSLR on their telescopes vs. a very expensive [sbig.com] purpose-made camera. There are a few small companies such as Hutech [hutech.com] which can perform this service under warranty.

Why?

Nebulas and stars in particular emit light (human-visible and not) in a variety of specific wavelengths. These particular wavelengths are produced by ionized elements in the star or nebula complex. In your run-of-the-mill nebula, copious amounts of Hydrogen-alpha and doubly-ionized Oxygen tend to produce much of the light. H-alpha's emission line is deep in to the red spectrum, which the IR cut filter on DSLRs dutifully blocks from reaching the sensor. Removing this filter lets the DSLR capture additional light and detail from the nebula... stuff you wouldn't get with a stock DSLR.

If you take a stock DSLR and try to image (for example) the Horsehead Nebula [wikipedia.org], you're not going to get far because the thing emits almost entirely in the H-alpha band. Put on a camera that doesn't cut the deep red, and you'll get a result that's closer to what you'd expect.

There is a trade-off to doing this mod, of course... in that you're effectively turning your DSLR into a IR camera, and if you want it to be close to normal again, you'll need to put a IR filter on your lens.