Ethics of Hubble photography

[Doug Nelson]

I thought of a topic that combines two other popular topics here, retouching ethics and astrophotography. Published photos from Hubble look nothing at all like "real life". In fact, they're heavily manipulated to be as pretty as possible. Although I love the manipulated Hubble photos, it does make me wonder about how scientific it is to present these as "official" space photos. The sensibility strikes me as being closer to Hollywood than science.

Thoughts?

[Gary Richardson]

Gotta agree with you Doug.

Although I can't think of how else you'd represent a star that only emitted say Infra Red radiation.

Might help if they stated up front that what they were showing was a visual representation, and not de-facto data.

[Gooner68]

I believe that Hubble and other telescopes don't shoot their images in full color, but take separate frames using different filters (Oxygen III, Hydrogen Alpha & Sulphur II). These are effectively the R G B channels of an ordinary picture, thus the full color images from Hubble are a composite of the various colored filters. Again, you can use PS techniques, like reducing noise to bring out more detail in the objects you are trying to observe.

Whilst I agree the colored images are visually stunning, and do a great PR job for NASA, I'm sure the astronomers do get value from these and the individual filtered shots.

You can actually try and do these yourself. The Hubble raw data is stored in a format called FITS (Flexible Image Transport System) for which there is a Photoshop plugin (and it's free) - The plug-in is similar to using RAW camera files

http://www.spacetelescope.org/project/fits_liberator/

From here you can d/l the plugin and raw files to produce your own images.

Cheers
Steve

[RichardBrackin]

http://www.spacetelescope.org/projec.../download.html

I think this is the link here. The other one appeared to be dead.

Here's a nice little article too...
http://hubblesource.stsci.edu/servic...es/2005-02-10/

I used to know a contractor in Huntsville, AL that did this but sadly have lost touch with him.

[Gooner68]

Thanks Richard,

I didn't check the link.....oops....

[RichardBrackin]

Wow!!!
This is FUN!
From what I've figured out in the first 10 minutes:

When you open the FITS image editor, I move sliders till no green clipping shows up. Here's what they say about the different settings in teh FITS editor.

A logarithmic representation of the pixel values tends to suppress the bright parts of the image, i.e. the stars, and to enhance the fainter part, e.g. nebulosity. This can be desirable if the ‘faint stuff’ needs ‘a boost’, but a logarithmic stretch function can also reduce the contrast in an image, producing a lower dynamic range...

I didn't use the actions but did manual Level, Curve, Hue/Sat operations for each color.

I put Blue at bottom, Green in middle and Red at top. You can base it on the numbers at the beginning of the file name.

First the individual exposure (taken through three different filters): 1. 673n (Sulphur) shown in red in the final image), 2. 656n (hydrogen, green), 3. 502n (oxygen, blue),

When time permits, I am going through all the images and goofing around with them.
There's a couple of things in the tutorial that don't seem to make sense in CS2:

Step 5 is very very important if you're doing this manually:

Remember to check the box "Use Previous Layer to Create Clipping Mask" ...

In CS2 you need to be sure your layers are in this order from bottom to top for each of the respective RGB imgaes: Levels, Curves, Hue/Sat

Then, for each color, beginning at the 'Levels' layer, select it and go up to the arrow at the top of the Layers palette and select 'make clipping mask'
Do this for all three adjustment layers for all three colors.

Other than that .. this is really cool stuff. You've gotta try it!!!
Here's my first try:

[CJ Max]

wallets. Who would want to authorize the spending of more money based on dull black and white images? Color and pizzaz - that's the name of the game. Black & white tells, but color sells! Make the customer feel as if he's really getting a Big Bang for his buck. Then slip in some larger numbers in next year's budget...

Does your wallet feel a wee bit lighter now? Mine does.

Cliff.