;+ ; NAME: ; zplot ; PURPOSE: ; Plot differential refraction as a function of wavelength. ; DESCRIPTION: ; CATEGORY: ; 2-D plotting ; CALLING SEQUENCE: ; INPUTS: ; OPTIONAL INPUT PARAMETERS: ; KEYWORD INPUT PARAMETERS: ; OUTPUTS: ; KEYWORD OUTPUT PARAMETERS: ; COMMON BLOCKS: ; SIDE EFFECTS: ; RESTRICTIONS: ; PROCEDURE: ; MODIFICATION HISTORY: ; 1991 - Written by Marc W. Buie, Lowell Observatory ;- pro zplot,pressure,temp,water z=[75.,10.,0.,20.,30.,40.,50.,60.,70.]/!radeg sz = 1./cos(z) am = sz - 0.0018167*(sz-1.0) - 0.002875*(sz-1.0)^2 - 0.0008083*(sz-1.0)^3 wave=indgen(200.)/200.*.57+.5 nw = n_elements(wave) nz = n_elements(z) dr = difref(wave,pressure,temp,water,z[0]) ytitle='Differential Refraction (arc-seconds)' xtitle='Wavelength (Angstroms)' title=string('T=',temp,'!9%!3C P=',fix(pressure),' mm Hg H!d2!n0=',water,' mm Hg',format='(a,f5.1,a,i4,a,i4,a)') plot,wave*10000.0,dr,xrange=[4900.0,11000.0],xtitle=xtitle,ytitle=ytitle,title=title xyouts,wave[nw-1]*10000.0,dr[nw-1],string(am[0],format='(f5.2)') for i=1,nz-1 do begin dr = difref(wave,pressure,temp,water,z[i]) oplot,wave*10000.0,dr xyouts,wave[nw-1]*10000.0,dr[nw-1],string(am[i],format='(f5.2)') end return end