Hydrogen and dust in Rosette Nebula

orin stepanek · Post by **orin stepanek** » Fri Dec 23, 2005 2:58 pm

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

harry · Post by **harry** » Fri Dec 23, 2005 11:17 pm

I agree with you, it is the natural colours.

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

nickwright · Post by **nickwright** » Thu Jan 05, 2006 6:14 pm

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.

orin stepanek · Post by **orin stepanek** » Thu Jan 05, 2006 8:06 pm

edited
Orin

Empeda2 · Post by **Empeda2** » Fri Jan 06, 2006 9:24 am

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

nickwright · Post by **nickwright** » Fri Jan 06, 2006 12:23 pm

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.

Empeda2 · Post by **Empeda2** » Fri Jan 06, 2006 12:46 pm

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?

nickwright · Post by **nickwright** » Fri Jan 06, 2006 12:49 pm

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.

Empeda2 · Post by **Empeda2** » Fri Jan 06, 2006 1:42 pm

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

nickwright · Post by **nickwright** » Fri Jan 06, 2006 2:05 pm

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.

Empeda2 · Post by **Empeda2** » Fri Jan 06, 2006 2:12 pm

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)