Quote:
Originally Posted by Placidus
That's a beautiful image, Greg. Trish and I much prefer the "with narrowband" version, as it shows so much more structure.
A question that I grapple with: when is what you see with an OIII filter OIII emission, when is it reflection nebulosity that just happens to include the exact colour of OIII, and when is it a mixture of both?
If the filters were perfect, and had 100% transmissivity in their bandpass and no transmissivity elsewhere, perhaps one measures A/D counts per hour through the OIII filter, and counts per hour through the OIII filter, and one has something like:
Fraction of OIII = OIII counts / Blue counts
Fraction of Reflection = the rest
In the real world, one would have to take the efficiency of the filters into account.
Once again, a lovely image.
Best,
Mike
|
Thanks M and T. My thought would be that reflection nebula targets like NGC6726 and the Pleaides don't really show up in O111 images as I recall.
So I expect this to be mainly simply areas of oxygen gas. I haven't done any checks but that is what I would expect to find.
Mike S's recent Blue Horsehead is a good reflection nebula and I bet nothing shows up in O111 on it.
Greg.
