phot.flux - an Addendum
Frederic V. "Rick" Hessman
hessman at Astro.physik.Uni-Goettingen.DE
Tue Nov 8 02:53:18 PST 2005
> Don't want to step on any radio astronomer's toes, but flux density
> is flux. Yes, I know, it's monochromatic flux per unit
> frequency, but where's the distinction between bolometric flux,
> monochromatic flux per unit frequency, and monochromatic flux per
> unit wavelength? Do we also then have to support the use of
> candela's, lux's, and the lot - also physical (even SI!) terms for
> the same things? How about (see, e.g., Mihalas):
> phot.flux generic net rate of radiant
> energy flow per unit area and time
> phot.flux.freq monochromatic flux per unit
> frequency, flux density
> phot.flux.wave monochromatic flux per unit wavelength
> phot.flux.bol bolometric flux
> phot.flux.Eddington Eddington flux = flux / 4PI
> I was going to suggest adding phot.flux.astr (that terrible factor
> of PI or /1PI, depending upon how you look at it!), but I won't......
Sorry - should have re-read the 1.02 documentation: "flux density"
has been generalized beyond it's normal use. How do we then
distinguish between the many different forms? By units alone, i.e.
non-UCD things? That works fine for things like lengths and times
and masses, since the physical quantities are well defined beyond
their units, but F_nu and F_lambda are totally different quantities
and this fact is utterly independent of the units.
phot.flux.perDecade nu*F_nu, lambda*F_lambda,...
Looking at the current list, I'd also like to complain about
Since when is surface brightness a flux? Surface brightness is an
intensity and intensity != flux. So...
phot.intensity generic directed
rate of radiant energy flow per unit area, time, and solid angle,
phot.intensity.bol (not generally
needed, but here for symmetry)
I know this is a bit of a change, but I frankly didn't notice
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