wiki:astronomy:observational_astronomy:observational_astronomy:extinction

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
wiki:astronomy:observational_astronomy:observational_astronomy:extinction [2023/11/14 13:02] Roy Proutywiki:astronomy:observational_astronomy:observational_astronomy:extinction [2023/11/14 13:11] (current) Roy Prouty
Line 35: Line 35:
  
 mbmt=2.5log10IbλItλ=2.5log10[exp(secztbαλ(x)dx)] mbmt=2.5log10IbλItλ=2.5log10[exp(secztbαλ(x)dx)]
 +
 +Let's carefully take the log-base-10 of the exponential...
 +mbmt=2.5log10(e)(secztbαλ(x)dx)
 +
 +Finally, recalling that we want to calibrate to the top-of-the-atmosphere, we find
 +
 +mt=mb+2.5log10(e)(secztbαλ(x)dx)
 +
 +So we find that the top-of-the-atmosphere magnitude is our bottom-of-the-atmosphere = top-of-telescope magnitude with some additional magnitude that was "extincted" away from incidence as the radiance traversed the atmosphere.\\ \\
 +
 +Note that the F or I used in the above equations are //not// counts. They must be some unit of power. So radiance, flux, energy per second (power), or even counts-per-second.
 +
 +----
 +Sources
 +  - Lifted with minor modification from: https://slittlefair.staff.shef.ac.uk/teaching/phy241/lectures/l07/