10 REM CCDLIMIT.BAS CCD Limits 20 REM by Bradley E. Schaefer 30 FOR I=1 TO 5 : READ WA(I) : NEXT I 40 DATA 0.365, 0.44, 0.55, 0.7, 0.9 50 FOR I=1 TO 5 : READ Q(I) : NEXT I 60 DATA 15.0, 25.0, 40.0, 56.0, 26.0 70 FOR I=1 TO 5 : READ MO(I) : NEXT I 80 DATA -10.93, -10.45, -11.05, -11.90, -12.70 90 REM Input for position 100 RD=3.14159/180.0 110 INPUT "Zenith distance (deg.) : ";Z 120 AM=180.0 : REM Moon phase (deg.; 0=FM, 90=FQ/LQ, 180=NM) 130 ZM=180.0 : REM Zenith distance of Moon (deg.) 140 RM=180.0 : REM Angular distance to Moon (deg.) 150 ZS=180.0 : REM Zenith distance of Sun (deg.) 160 RS=180.0 : REM Angular distance to Sun (deg.) 170 REM Input for the Site and Date 180 TS=1.0 : REM FWHM of seeing in V at zenith 190 RH=40.0 : REM relative humidity (%) 200 TE=15.0 : REM Air temperature (deg. C) 210 LA=30.0 : REM Latitude (deg.) 220 AL=1000.0 : REM Altitude above sea level (m) 230 M=2.0 : REM Month (1=Jan, 12=Dec) 240 Y=1998.0 : REM Year 250 REM Input for the telescope and detector 260 D=20.32 : REM Telescope aperture (cm) 270 TP=.91 : REM Pixel size (") 280 DS=4.0 : REM Diameter of secondary (cm) 290 NM=2 : REM Number of mirrors (-) 300 NL=2 : REM Number of lens/glass in path (-) 310 RN=15.0 : REM Read noise of CCD (electrons) 320 INPUT "Enter V-band magnitude of star: ";MV 330 CI=.7 : REM Color index [B-V] for star (mag) 340 INPUT "Exposure time (seconds): ";E 350 NR=1 : REM Number of CCD readouts (-) 360 TA=1.0 : REM Radius of photometry aperture (") [best : TA=~TS] 370 GOSUB 1000 : REM Extinction subroutine 380 GOSUB 2000 : REM Sky subroutine 390 REM Calculate counts from star and sky 400 MA(1)=MV+2.35*CI-.6 : REM U 410 MA(2)=MV+CI : REM B 420 MA(3)=MV : REM V 430 MA(4)=MV-.75*CI : REM R 440 MA(5)=MV-1.6*CI : REM I 450 GOSUB 3000 : REM CT subroutine 460 REM Calculate SNR (see PASP article for exact formula) 470 P=3.14159*(TA/TP)^2 480 IF P<1.0 THEN P=1.0 490 FOR I=1 TO 5 500 VA=NS(I)+P*NB(I)+P*NR*RN*RN 510 SN(I)=NS(I)/SQR(VA) 520 SI(I)=1.086/SN(I) 530 NEXT I 540 PRINT : PRINT "For star with U, B, V, R, I "; 550 PRINT USING " #####.##"; MA(1), MA(2), MA(3), MA(4), MA(5) 560 PRINT " their respective SNR are "; 570 PRINT USING " #####.##"; SN(1), SN(2), SN(3), SN(4), SN(5) 580 PRINT " with 1-sigma errors (mag.) of "; 590 PRINT USING " #####.##"; SI(1), SI(2), SI(3), SI(4), SI(5) 600 END 1000 REM Extinction Subroutine 1010 FOR I=1 TO 5: READ OZ(I): NEXT I 1020 DATA 0.000, 0.000, 0.031, 0.008, 0.000 1030 FOR I=1 TO 5: READ WT(I): NEXT I 1040 DATA 0.074, 0.045, 0.031, 0.020, 0.015 1050 LT=LA*RD 1060 RA=(M-3)*30.0*RD 1070 SL=LA/ABS(LA) 1080 REM Airmass for each component 1090 ZZ=Z*RD 1100 XG=1/(COS(ZZ)+.0286*EXP(-10.5*COS(ZZ))) 1110 XA=1/(COS(ZZ)+.0123*EXP(-24.5*COS(ZZ))) 1120 XO=1/SQR(1.0-(SIN(ZZ)/(1.0+(20.0/6378.0)))^2) 1130 REM UBVRI extinction for each component 1140 FOR I=1 TO 5 1150 KR=.1066*EXP(-1*AL/8200)*((WA(I)/.55)^-4) 1160 KA=.1*((WA(I)/.55)^-1.3)*EXP(-1*AL/1500) 1170 KA=KA*((1-.32/LOG(RH/100.0))^1.33)*(1+SL*SIN(RA)) 1180 KO=OZ(I)*(3.0+.4*(LT*COS(RA)-COS(3*LT)))/3.0 1190 KW=WT(I)*.94*(RH/100.0)*EXP(TE/15)*EXP(-1*AL/8200) 1200 K(I)=KR+KA+KO+KW 1210 DM(I)=KR*XG+KA*XA+KO*XO+KW*XG 1220 NEXT I 1230 REM Write results and return 1240 PRINT : PRINT "Airmass (gas, aerosol, ozone): "; 1250 PRINT USING "####.## "; XG, XA, XO 1260 PRINT "Extinction Coefficients (UBVRI): "; 1270 PRINT USING "####.## "; K(1), K(2), K(3), K(4), K(5) 1280 PRINT "Total Extinction (UBVRI): "; 1290 PRINT USING "####.## "; DM(1), DM(2), DM(3), DM(4), DM(5) 1300 RETURN 2000 REM SKY Subroutine 2010 FOR I=1 TO 5: READ BO(I): NEXT I 2020 DATA 8.0E-14, 7.0E-14, 1.0E-13, 1.0E-13, 3.0E-13 2030 FOR I=1 TO 5: READ CM(I): NEXT I 2040 DATA 1.36, 0.91, 0.00, -0.76, -1.17 2050 FOR I=1 TO 5: READ MS(I): NEXT I 2060 DATA -25.96, -26.09, -26.74, -27.26, -27.55 2070 X=1/(COS(ZZ)+.025*EXP(-11*COS(ZZ))) : REM air mass 2080 XM=1/(COS(ZM*RD)+.025*EXP(-11*COS(ZM*RD))) : REM air mass Moon 2090 IF ZM>90.0 THEN XM=40.0 2100 XS=1/(COS(ZS*RD)+.025*EXP(-11*COS(ZS*RD))) : REM air mass Sun 2110 IF ZS>90.0 THEN XS=40.0 2120 FOR I=1 TO 5 2130 REM Dark night sky brightness 2140 BN=BO(I)*(1+.3*COS(6.283*(Y-1992)/11)) 2150 BN=BN*(.4+.6/SQR(1.0-.96*((SIN(ZZ))^2))) 2160 BN=BN*(10^(-.4*K(I)*X)) 2170 REM Moonlight brightness 2180 MM=-12.73+.026*ABS(AM)+4E-09*(AM^4) : REM moon mag in V 2190 MM=MM+CM(I) : REM Moon mag 2200 C3=10.0^(-.4*K(I)*XM) 2210 FM=6.2E+07*(RM^-2)+(10^(6.15-RM/40)) 2220 FM=FM+(10^5.36)*(1.06+((COS(RM*RD))^2)) 2230 BM=10^(-.4*(MM-MO(I)+43.27)) 2240 BM=BM*(1-10^(-.4*K(I)*X)) 2250 BM=BM*(FM*C3+440000.0*(1-C3)) 2260 REM Twilight brightness 2270 HS=90.0-ZS : REM Height of Sun 2280 BT=10^(-.4*(MS(I)-MO(I)+32.5-HS-(Z/(360*K(I))))) 2290 BT=BT*(100/RS)*(1.0-10.0^(-.4*K(I))) 2300 REM Daylight brightness 2310 C4=10.0^(-.4*K(I)*XS) 2320 FS=6.2E+07*(RS^-2)+(10^(6.15-RS/40)) 2330 FS=FS+(10^5.36)*(1.06+((COS(RS*RD))^2)) 2340 BD=10^(-.4*(MS(I)-MO(I)+43.27)) 2350 BD=BD*(1-10^(-.4*K(I)*X)) 2360 BD=BD*(FS*C4+440000.0*(1-C4)) 2370 REM Total sky brightness 2380 IF BD>BT THEN GOTO 2410 2390 B(I)=BN+BD 2400 GOTO 2420 2410 B(I)=BN+BT 2420 IF ZM<90.0 THEN B(I)=B(I)+BM 2430 NEXT I 2440 PRINT "Sky brightness (UBVRI):"; 2450 PRINT USING " ##.#^^^^"; B(1), B(2), B(3), B(4), B(5) 2460 RETURN 3000 REM Subroutine CT 3010 FOR I=1 TO 5 : READ DL(I) : NEXT I 3020 DATA 0.068, 0.098, 0.089, 0.22, 0.24 3030 FOR I=1 TO 5 : READ RE(I) : NEXT I 3040 DATA 0.83, 0.86, 0.88, 0.87, 0.90 3050 FOR I=1 TO 5 : READ TR(I) : NEXT I 3060 DATA 0.970, 0.983, 0.987, 0.983, 0.980 3070 FOR I=1 TO 5 : READ TF(I) : NEXT I 3080 DATA 0.70, 0.70, 0.70, 0.70, 0.70 3090 REM Seeing 3100 FOR I=1 TO 5 3110 X=1.0/(COS(Z/57.28)) 3120 T1=(TS^2)*(X^1.2)*((WA(I)/.55)^-.4) 3130 T2=5.54*((3600.0*57.28*(WA(I)/10000.0)/D)^2) 3140 TT(I)=SQR(T1+T2) : REM TOTAL SEEING FWHM (") 3150 NEXT I 3160 REM Efficiencies 3170 FOR I=1 TO 5 3180 EF(I)=(Q(I)/100.0)*TF(I)*(RE(I)^NM)*(TR(I)^(2.0*NL)) 3190 F(I)=1-EXP(-2.77*((TA/TT(I))^2)) : REM Fraction in photometry aperture 3200 NEXT I 3210 A=(3.14159/4.0)*(D^2-DS^2) : REM Light-collecting area 3220 REM Source and sky counts 3230 FOR I=1 TO 5 3240 IN=10^(-.4*(MA(I)-MO(I)+DM(I))) 3250 PE=(WA(I)/10000.0)/(6.62E-27*2.997E+10) 3260 NS(I)=IN*F(I)*A*EF(I)*E*DL(I)*PE 3270 NB(I)=B(I)*A*EF(I)*E*DL(I)*PE*(TP^2) 3280 NEXT I 3290 PRINT : PRINT "Star counts in photometry aperture (UBVRI):"; 3300 PRINT USING " #####."; NS(1), NS(2), NS(3), NS(4), NS(5) 3310 PRINT "Sky counts per pixel (UBVRI): "; 3320 PRINT USING " #####."; NB(1), NB(2), NB(3), NB(4), NB(5) 3330 RETURN 9991 REM ============================== 9992 REM FROM "ASTRONOMICAL COMPUTING," 9993 REM SKY & TELESCOPE, MAY 1998 9994 REM ==============================