by Chris Peterson » Wed Apr 10, 2024 1:25 pm
Christian G. wrote: ↑Wed Apr 10, 2024 12:58 pm
Is that to say that upon seeing the red/pink during totality, we are seeing with our own eyes the actual H-alpha colours of distant pink/red nebulae?
The Sun is made of hot hydrogen. That hydrogen is emitting the same red light we see in emission nebulas. But where its gas is optically thick (what we call the "surface") it is a blackbody (thermal) source of white light that is a million times brighter than the narrowband hydrogen emissions. An eclipse blocks the bright white light so we can see any glowing hydrogen being carried above the surface (prominences). It's the same thing we see when we view the Sun through a filter that isolates the hydrogen emission line (except in that case we can see the entire surface, not just prominences above it).
(The color we see is a narrow line at 656 nm, which is deep ruby red. In nebulas we always see it photographically, and usually mixed with other colors from reflections and the emissions of other elements. That, combined with processing techniques, means we see it as a range of reddish colors covering pink, magenta, and others. But visually, when there's no other light? It's red. That's what I saw during this eclipse, and every other eclipse where the Sun has been active enough to have high prominences. No pink, but intense, deep red.)
[quote="Christian G." post_id=338214 time=1712753934 user_id=147043]
[quote="Chris Peterson" post_id=338084 time=1712161142 user_id=117706]
The red/pink is H-alpha.
[/quote]
Is that to say that upon seeing the red/pink during totality, we are seeing with our own eyes the actual H-alpha colours of distant pink/red nebulae?
[/quote]
The Sun is made of hot hydrogen. That hydrogen is emitting the same red light we see in emission nebulas. But where its gas is optically thick (what we call the "surface") it is a blackbody (thermal) source of white light that is a million times brighter than the narrowband hydrogen emissions. An eclipse blocks the bright white light so we can see any glowing hydrogen being carried above the surface (prominences). It's the same thing we see when we view the Sun through a filter that isolates the hydrogen emission line (except in that case we can see the entire surface, not just prominences above it).
(The color we see is a narrow line at 656 nm, which is deep ruby red. In nebulas we always see it photographically, and usually mixed with other colors from reflections and the emissions of other elements. That, combined with processing techniques, means we see it as a range of reddish colors covering pink, magenta, and others. But visually, when there's no other light? It's red. That's what I saw during this eclipse, and every other eclipse where the Sun has been active enough to have high prominences. No pink, but intense, deep red.)