What color is dust?

[Ags]

In most images of dust it appears brown, but I recently saw a super-deep photo of the dust between the Orion nebula and the Horsehead and there the dust was rendered in red and appeared to be a Ha region...?

[Jessun]

Funny, you pretty much nailed why I image at all! Inevitably you'll ask the question what am I looking at here?

I will follow this thread with interest as I have no idea but would like to know too!

Could dust come in many forms; reflective or blocking? Dust on its own doesn't sound like a candidate for emitting it's own radiation out there...

[jimmyjamjoejoe]

I guess it depends what the dust came from...

[ollypenrice]

...or if it's scattering starlight? M45? Then blue!

Brown is my answer. Red arises when you shortcut by using lots of Ha. If you take enough LRGB around M42 it is all there and brown. If you're in a hurry and get it through a smaller amount of Ha it will come out red.

Olly

[Ags]

...or if it's scattering starlight? M45? Then blue!

Brown is my answer. Red arises when you shortcut by using lots of Ha. If you take enough LRGB around M42 it is all there and brown. If you're in a hurry and get it through a smaller amount of Ha it will come out red.

Olly

Ah-ha!

[ollypenrice]

Mind you, if the area responds in Ha it must because there is Ha there, so a mixture of backlit dust and ionized hydrogen is presumably present. In this one the dust was unaffected by the Ha when I combined them becuae there is a ton of LRGB data here. The Ha showed in the dark sky around M42, which turned a deep purple colour. (With apologies to Rob!!!!)

Olly