Usage of baarsTaperFactor

Return to directory of Todd's CASA extensions

Converts a taper in dB to the constant X in the formula FWHM=X*lambda/D for a parabolic illumination pattern using either equation 18 from ALMA Memo 456 or Equation 4.13 from Baars' 2007 book. We assume that taper_dB comes in as a positive value. See also effectiveTaper, goldsmithTaperFactor, and primaryBeamArcsec.

Usage:

au.baarsTaperFactor(taper_dB, use2007formula=True)

• if use2007formula == True: use 1.269 - 0.566*tau + 0.534*(tau)**2 - 0.208*(tau)**3
• if use2007formula == False: use 1.243 - 0.343*tau + 0.12*(tau)**2

Example:

CASA <7>: au.baarsTaperFactor(12)
  Out[7]: 1.1572237723314809

-- ToddHunter - 2013-07-11