Hubble Snaps Pix Of Dying Supernova

The Hubble has taken some great pictures of a supernova according to CNN. You can get a more indepth article, and more pictures from Space.com story on the same subject. Purty explosions!

Comments

Re:Semi-OT : Bigger Pictures?

[HellKrisp]

This big enough? :) (got from here)

Re:The amazing thing is the colours

[LMCBoy]

The colors in this particular image are especially misleading.

In most HST "pretty-picture" images, the colors are at least representative of reality. You take three images, through "blue", "green" and "red" filters, then stack them, with each layer driving the appropriate R,G,B value of the color composite. The result may be more saturated than reality, but you get at least some idea of how it would look to your eye.

However, this image is a stack of "narrow-band" images, centered on particular atomic emission lines. These narrow-band images are incredibly useful scientifically, because they let you study the energetics and chemistry inside the SN remnant, as well as the shock conditions of the gas. However, the colors are assigned arbitrarily, and have no connection to how the object would actually look.

Unfortunately I saw no caveat to this effect in either the CNN article (no suprise) nor the space.com article (mildly disappointing).

I mean, why not add a phrase in there like: "In reality, Cas A is not so colorful. The vivid colors are added to the image to help scientists map out different chemicals and their ionization states, which allows them to determine the strength of the original explosion, and how it has evolved to its present state."