Starship Asterisk*

http://antwrp.gsfc.nasa.gov/apod/ap051223.html
Is this in natural color? I imagine that is why it is called Rosette. Looks pretty violent and stormy. Yet this makes for an Awesome sight.
Orin

I agree with you, it is the natural colours.

If the colour was ajusted the image would have state that.

its semi-natural colours, hydrogen alpha is in the red area of the spectrum, but these images have been altered to include the yellow part.

edited
Orin

I would suspect that that image is also semi-natural, I suspect they've magnified the h-alpha in that too.

the h-alpha isn't strictly magnified, but since its the only narrow band filter, it is enhanced relative to the r and i bands. but thats what all images do.

Is that the same reason why old images also have a much larger red-tinge to them? Something to do with the light detection of the film used?

I don't know about the older photographic images, but red is an abundant colour in astrophysics, its the colour that hydrogen glows in space, so it can be seen a lot.

Yep, that and the green of oxygen in nebulae....

yes, but generally oxygen is much less abundant, so the lines are much weaker than those from hydrogen. nitrogen can be quite strong too, also in the red.

It's fasinating isn't it - there was an APOD fairly recently that showed a both an emission nebulae (red) and scattered starlight (blue) in the same image - really beautiful scene. 8)