pro testctel,crn,cl01,cl02,reso,i1,i2,di,DTL=dtl
    
    if N_PARAMS( ) lt 1 then begin
       print,'testctel,crn,cl01,cl02,reso,i1,i2,di,/dtl'
       print,"crn=2065 & cl01=165.050 & cl02=195.505"
       return
    endif
    dt12x=fltarr(15)
    dt12r=dt12x
  ; dt21x=dt12x & dt21r=dt12r
    for ii=i1,i2,di do begin
        crni=crn+ii
        if keyword_set(dtl) then testtech,crni,cl01,cl02,reso,dt12xi,dt12ri,/dtl $
                            else testtech,crni,cl01,cl02,reso,dt12xi,dt12ri
        dt12x(ii)=dt12xi
        dt12r(ii)=dt12ri
    endfor
    ttl='CR'+strtrim(crn,2)+' Cl01='+strtrim(cl02,2)+' Cl02='+strtrim(cl01,2)+' Dotted: Roger, Solid: Xuepu'
    ofl='testctel_'+strtrim(crn,2)+'_'+strtrim(cl01,2)+'_'+strtrim(cl02,2)+'_'+STRTRIM(reso,2)+'.ps'
    psout,011,ofl
    plot,dt12x,xrange=[0,13],yrange=[2.2,2.4],xsty=1,ysty=1,title=ttl,xtitle='Carrington Rotation Number starting from CR'+STRTRIM(crn,2)+' (December)',ytitle='Time difference from Cl01 to Cl02 in days'
    oplot,dt12r,line=2
    ddt=(dt12x-dt12r)*86400
    mx=STRTRIM(MAX(ddt),2) & mn=STRTRIM(MIN(ddt),2)
    xyouts,0.25,2.37,'Difference between solid and dashed in second: Max='+mx+' Min='+mn
    CASE 1 OF
     reso eq 360: lim=0.166667
     reso eq 100: lim=0.05
     reso eq 60:  lim=0.0166667
     reso eq 10:  lim=0.00277778
     reso eq 1:   lim=0.000277778
    ENDCASE
    xyouts,0.25,2.23,'Longitude resolution of '+STRTRIM(lim,2)+' degrees'
 
    psdone
    print,ofl

end
    
pro testtech,crn,cl01,cl02,reso,dt12x,dt12r,DTL=dtl

if keyword_set(dtl) then begin
   datetime_scrncl0_200905,crn,cl01,reso=reso,cl0i1,year1,month1,dayi1,/dtl
   datetime_scrncl0_200905,crn,cl02,reso=reso,cl0i2,year2,month2,dayi2,/dtl
endif else begin
   datetime_scrncl0_200905,crn,cl01,reso=reso,cl0i1,year1,month1,dayi1
   datetime_scrncl0_200905,crn,cl02,reso=reso,cl0i2,year2,month2,dayi2
endelse
if year1 ne year2 then $
   CASE 1 OF
    year1 gt year2: begin
                    dayi2=dayi2-FIX(dayi2)
                    month2=1
                    end
    year1 lt year2: begin
                    dayi1=dayi1-FIX(dayi1)
                    month1=1
                    end
   ENDCASE
print,'month1,dayi1:',month1,dayi1
print,'month2,dayi2:',month2,dayi2
if month1 ne month2 then $
   CASE 1 OF
    month1 gt month2: begin
                     CASE 1 OF 
                      month2 eq 1: dayi2=dayi2-31
                      month2 eq 2: dayi2=dayi2-28
                      month2 eq 3: dayi2=dayi2-31
                      month2 eq 4: dayi2=dayi2-30
                      month2 eq 5: dayi2=dayi2-31
                      month2 eq 6: dayi2=dayi2-30
                      month2 eq 7: dayi2=dayi2-31
                      month2 eq 8: dayi2=dayi2-31
                      month2 eq 9: dayi2=dayi2-30
                      month2 eq 10: dayi2=dayi2-31
                      month2 eq 11: dayi2=dayi2-30
                      month2 eq 12: dayi2=dayi2-31
                     ENDCASE 
                     month2=month2+1
                      end
    month1 lt month2: begin
                     CASE 1 OF
                      month1 eq 1: dayi1=dayi1-31
                      month1 eq 2: dayi1=dayi1-28
                      month1 eq 3: dayi1=dayi1-31
                      month1 eq 4: dayi1=dayi1-30
                      month1 eq 5: dayi1=dayi1-31
                      month1 eq 6: dayi1=dayi1-30
                      month1 eq 7: dayi1=dayi1-31
                      month1 eq 8: dayi1=dayi1-31
                      month1 eq 9: dayi1=dayi1-30
                      month1 eq 10: dayi1=dayi1-31
                      month1 eq 11: dayi1=dayi1-30
                      month1 eq 12: dayi1=dayi1-31
                     ENDCASE
                     month1=month1+1
                      end
   ENDCASE
dt12x=dayi1-dayi2
dct=(1-cl01/360.) - (1-cl02/360.)
dt12r=dct*27.2753
print,'crn,cl01,cl02:',crn,cl01,cl02
print,'month1,month2:',month1,month2
print,'dt12x,dt12r:',dt12x,dt12r

end