Atmospheric extinction
Quantify the cost of imaging low.
Estimate pressure-adjusted airmass, magnitude loss and remaining transmission at a target altitude.
Purpose and method
What this calculator does
How much signal will the atmosphere remove? Estimate pressure-adjusted airmass and transmission loss.
In words: Magnitude loss is the local extinction coefficient multiplied by optical airmass.
Change a value and the result updates immediately. The extinction coefficient varies with wavelength, aerosols, humidity and transparency. Use a locally measured coefficient for photometric work.
Working geometry
Atmospheric light path
Lower target altitude lengthens the atmospheric path and reduces received transmission.
Inputs
Altitude and atmosphere
Calculated now
Atmospheric loss
- Pressure-adjusted airmass
- 1.32
- Extinction
- 0.26 mag
- Remaining transmission
- 78.35 %
Governing equation
In words: Magnitude loss equals the local extinction coefficient multiplied by pressure-adjusted optical airmass.
Show the working
The calculator applies the equation above to the values currently entered, without rounding until this display.
- Pressure-adjusted airmass
- 1.32
- Extinction
- 0.26 mag
- Remaining transmission
- 78.35 %
The extinction coefficient varies with wavelength, aerosols, humidity and transparency. Use a locally measured coefficient for photometric work.