Dim Dc_year(3) R_d=180/Pi ! Constant to change radians to degrees D_r=Pi/180 ! Constant to change degrees to radians ' ' ' Rez=Xbios(4) ! Determine the resolution 1 = medium, 2 = High ' ' Since the plotting and such are set up for Med. and High rez, ' don't allow the program to be run in low resolution ' If Xbios(4)=0 Then Alert 1,"Please switch to|Medium resolution!",1,"Ok!",Dummy% End Endif ' ' ' Start the program !! ' Repeat Hidem ! Hide the mouse cursor or it'll get in the way ' ' Input the Year of curiosity ' Input " Year? ",Y ' ' The next few lines calculate the Julian date for Jan. 1 of the desired year. ' Y1=Y-1 M=13 D=1 Cls A=Int(Y1/100) B=2-A+Int(A/4) Jd=Int(365.25*Y1)+Int(30.6001*(M+1))+D+1720994.5+B ' ' Set up constants to find the date of opposition ' Stepper=32 Day=-16 Flag1=True ! Flag to detect when oppostion occurs Old_diff=0 Gosub Bell Cls Print At(30,12);" Working.."; ' ' Here we enter the loop to find the date of opposition by ' quartering the year first by 32 days, then 16, then 8... ' While Stepper>0.25 Iter=1 Flag2=False Repeat Te=Jd+Day-2415020 ! Number of days since 1/1/1900 Tc=Te/36525 ! Number of centuries since 1/1/1900 ' ! Find position of Sun and Jupiter at above date Gosub Position(Tc) ' When Diff = 0 then Jupiter is at opposition Diff=Abs(Abs(Ra_sun-Ra_jup)-180) ' Check flags to see if near or at opposition If Flag1=True And Old_diffDiff Then Flag1=False Else Flag1=True Endif Old_diff=Diff Day=Day+Stepper Iter=Iter+1 Until Flag2 ' ' Having detected that we're near opposition cut Stepper in two and ' start again and go back sufficient time to find actual time of ' opposition! ' Print "."; Day=Day-3*Stepper Stepper=Stepper/2 ' ' when stepper meets condition above leave loop ' Wend Print Print ' since there was a redcuton of the value of Day above increment it Day=Day+2*Stepper Gosub Bell Print ' ' calculate calendar date from Julian date ' Cls Gosub Opp_date(Day,Jd) Print ' ' Print out results ' If Day=0 Then Day=1 Endif If Day<=365 And Day>0 Then Print " The opposition of Jupiter occurred on day ";Day;" of the year ";Y;"." Endif If Day>365 Then Day1=Day-365 Print " There was no opposition of Jupiter in the year ";Y Y=Y+1 Print " but occurred on day ";Day1;" of the following year ";Y Endif Print Ra_sun=Ra_sun/15 Ra_jup=Ra_jup/15 Ra_s_min=Trunc(60*Frac(Ra_sun)) Ra_j_min=Trunc(60*Frac(Ra_jup)) Ra_sun=Trunc(Ra_sun) Ra_jup=Trunc(Ra_jup) Dc_s_min=Abs(Trunc(60*Frac(Dc_sun))) Dc_j_min=Abs(Trunc(60*Frac(Dc_jup))) Dc_sun=Trunc(Dc_sun) Dc_jup=Trunc(Dc_jup) Print Print " R.A. of the Sun at Opposition = ";Ra_sun;"H ";" ";Ra_s_min;"M" Print " Dec. of the Sun = ";Dc_sun;Chr$(248);" ";Dc_s_min;"'" Print Print " R.A. of Jupiter at Opposition = ";Ra_jup;"H ";" ";Ra_j_min;"M" Print " Dec. of Jupiter = ";Dc_jup;Chr$(248);" ";Dc_j_min;"'" Print Input " Press 'Return' to start plot ";A$ Gosub Bell ' ' Set up the limits for plotting ' Day_opp=Day Dc_year(1)=Dc_jup Dc_opp=Dc_jup Ra_opp=Ra_jup ' ' Calculate the starting position ' Day_start=Day-160 Te=Jd+Day_start-2415020 Tc=Te/36525 Gosub Position(Tc) Ra_start=Ra_jup Ra_start1=Ra_start/15 Ra_start$="R.A. Start = "+Str$(Trunc(Ra_start1))+"H "+Str$(Trunc((Ra_start1-Trunc(Ra_start1))*60))+"M" Dc_start=Dc_jup Dc_year(2)=Dc_start ' ' Calculate the end position ' Day_end=Day+160 Te=Jd+Day_end-2415020 Tc=Te/36525 Gosub Position(Tc) Ra_end=Ra_jup Dc_end=Dc_jup Ra_end1=Ra_end/15 Ra_end$="R.A. End = "+Str$(Trunc(Ra_end1))+"H "+Str$(Trunc((Ra_end1-Trunc(Ra_end1))*60))+"M" Dc_year(3)=Dc_end ' ' Sort Declinations of start, end and opposition positions to determine ' the range of degrees of declination traveled to determine Dc_step. ' Gosub Dc_sort ' ' Since R.A.'s go from 0 to 360 degrees[0 to 24 hours] we have to ' determine if the plot crosses from 359 to 1 degrees to keep the plot on ' scale. ' Fudge=0 ! Fudge factor if R.A. crosses the 0H boundary Ra_flag=0 If Ra_end180 And Ra_flag=1 Then Ra_jup=Ra_jup-Fudge Endif Diff_ra_start=Abs(Ra_start-Ra_jup) Ra_place=639-Abs(Diff_ra_start*Ra_step) Dc_place=Rez*200-Abs(Dc_jup-Dc_bottom)*Dc_step Diff=Ra_jup-O_ra_jup Draw To Ra_place,Dc_place ' ' If at the day of opposition draw a tic mark to show it ' If (Day_opp=Day_pos) Then Draw To Ra_place,Dc_place+5 Draw To Ra_place,Dc_place-5 Draw To Ra_place,Dc_place Endif O_ra_jup=Ra_jup Next Day_pos Dc_jup1=Trunc(Dc_jup*100)/100 ' ' Draw the end Dec. limit and label it. ' Draw To 639,Dc_place Dc_jup1h=Trunc(Dc_jup) Dc_jup1m=Abs(Trunc((Dc_jup-Dc_jup1h)*60)) Dc_text$=Str$(Dc_jup1h)+Chr$(248)+" "+Str$(Dc_jup1m)+"'" Dc_text$="Dec. = "+Dc_text$ If Dc_place<100 Then Text 500,Dc_place+6,100,Dc_text$ Else Text 500,Dc_place-2,100,Dc_text$ Endif Gosub Bell What_now: Repeat Until Mousek=0 Showm Alert 2,"Retrograde Drawing| Complete| Press any Key| to Continue",1,"Look|Print|QUIT ",Butn Hidem If Butn=2 Then Hardcopy Goto What_now Endif If Butn=3 Goto Drop_out Else Gosub Any_key Goto What_now Endif ' ' Asks if you want to do it again ' Drop_out: Input "Do you wish another year's plot (Y/N) ";Yes$ Until ((Yes$="n") Or (Yes$="N")) ' Return mouse cursor Showm End ' ' The following Procedure calculates the positions of the Sun and Jupiter ' for the given Julian Date. ' Procedure Position(Tx) ' The eccentricity of the Earth's orbit's orbit's orbit's orbit's orbitun-E_sun2 E_sun2=E_sun Wend ' Radius vector of the Sun R_sun=1.0000002*(1-Ecc_earth*Cos(E_sun*D_r)) ' the true anomaly of the Sun V_sun=2*Atn(Sqr((1+Ecc_earth)/(1-Ecc_earth))*Tan(E_sun*D_r/2))*R_d ' the true logitude of the Sun Sun_true_lng=L_sun+V_sun-M_sun ' Correction for nutation and abberation Omega_sun=259.18-1934.142*Tx ' Obiliquity of the Ecliptic Obilquity=Obilquity+0.00256*Cos(Omega_sun*D_r) Temp1=Cos(Obilquity*D_r)*Sin(Sun_true_lng*D_r) Temp2=Cos(Sun_true_lng*D_r) ' ' Now calculate the right ascension of the Sun and put it in ' the right quadrent ' Ra_sun=Atn(Temp1/Temp2) If Temp2>0 And Temp1<0 Then Ra_sun=Ra_sun+2*Pi Endif If Temp2<0 Then Ra_sun=Ra_sun+Pi Endif ' ' Calculate the declination position of the Sun ' Temp1=Sin(Obilquity*D_r)*Sin(Sun_true_lng*D_r) Temp2=Sqr(1-Temp1*Temp1) Dc_sun=Atn(Temp1/Temp2)*R_d Ra_sun=Ra_sun*R_d ' ' Now repeat the above for Jupiter ' L_jup=238.049257+3036.301986*Tx+0.0003347*Tx*Tx-1.65E-06*Tx*Tx*Tx A_jup=5.202561 Ecc_jup=0.04833475+0.00016418*Tx-4.676E-07*Tx*Tx-1.7E-09*Tx*Tx*Tx I_jup=1.308736-0.0056961*Tx+3.9E-06*Tx*Tx W_jup=273.277558+0.5994317*Tx+0.00070405*Tx*Tx+5.08E-06*Tx*Tx*Tx Omega_jup=99.443414+1.01053*Tx+0.00035222*Tx*Tx-8.51E-06*Tx*Tx*Tx M_jup=225.322833+3034.69202*Tx-0.000722*Tx*Tx E_diff=1 E_jup2=M_jup While Abs(E_diff)>1.0E-06 E_jup=M_jup+Ecc_jup*R_d*Sin(E_jup2*D_r) E_diff=E_jup-E_jup2 E_jup2=E_jup Wend Temp1=Sin(E_jup*D_r/2) Temp2=Cos(E_jup*D_r/2) Temp3=Sqr((1+Ecc_jup)/(1-Ecc_jup)) V_jup=Atn(Temp3*Temp1/Temp2) If (Temp1*Temp3)<0 And Temp2>0 Then V_jup=V_jup+2*Pi Endif If Temp2<0 Then V_jup=V_jup+Pi Endif V_jup=2*V_jup*R_d R_jup=A_jup*(1-Ecc_jup*Cos(E_jup*D_r)) U_jup=L_jup+V_jup-M_jup-Omega_jup Temp1=Cos(I_jup*D_r)*Sin(U_jup*D_r) Temp2=Cos(U_jup*D_r) Long_jup=Atn(Temp1/Temp2) If Temp2>0 And Temp1<0 Then Long_jup=Long_jup+2*Pi Endif If Temp2<0 Then Long_jup=Long_jup+Pi Endif Long_jup=Long_jup*R_d Long_jup=Long_jup+Omega_jup Temp1=Sin(U_jup*D_r)*Sin(I_jup*D_r) Temp2=Sqr(1-Temp1*Temp1) B_jup=Atn(Temp1/Temp2)*R_d Geo_sun_lng=Long_jup-Sun_true_lng Temp1=R_jup*Cos(B_jup*D_r)*Sin((Geo_sun_lng)*D_r) Temp2=R_jup*Cos(B_jup*D_r)*Cos((Geo_sun_lng)*D_r)+R_sun Long_jup_geo=Atn(Temp1/Temp2) If Temp2>0 And Temp1<0 Then Long_jup_geo=Long_jup_geo+2*Pi Endif If Temp2<0 Then Long_jup_geo=Long_jup_geo+Pi Endif Long_jup_geo=Long_jup_geo*R_d Temp_geo=Long_jup_geo Long_jup_geo=Long_jup_geo+Sun_true_lng Delta_jup=Sqr(R_sun*R_sun+R_jup*R_jup+2*R_jup*R_sun*Cos(B_jup*D_r)*Cos((Geo_sun_lng)*D_r)) Temp1=R_jup*Sin(B_jup*D_r)/Delta_jup Temp2=Sqr(1-Temp1*Temp1) Beta_jup=Atn(Temp1/Temp2)*R_d Temp1=Cos(Beta_jup*D_r)*Cos(Temp_geo*D_r) Temp2=Sqr(1-Temp1*Temp1) Elong_jup=Atn(Temp2/Temp1) Temp1=Sin(Long_jup_geo*D_r)*Cos(Obilquity*D_r)-Tan(Beta_jup*D_r)*Sin(Obilquity*D_r) Temp2=Cos(Long_jup_geo*D_r) Ra_jup=Atn(Temp1/Temp2) If Temp2>0 And Temp1<0 Then Ra_jup=Ra_jup+2*Pi Endif If Temp2<0 Then Ra_jup=Ra_jup+Pi Endif Ra_jup=Ra_jup*R_d Temp1=Sin(Beta_jup*D_r)*Cos(Obilquity*D_r)+Cos(Beta_jup*D_r)*Sin(Obilquity*D_r)*Sin(Long_jup_geo*D_r) Temp2=Sqr(1-Temp1*Temp1) Dc_jup=Atn(Temp1/Temp2)*R_d Return ' ' Procedure to sort the three important declinations of Jupiter, start,end, ' and opposition ' Procedure Dc_sort Switch=True While Switch=True For I%=1 To 2 If Dc_year(I%)13.5 Month=E-13 Endif If Month>2.5 Then Year=C-4716 Endif If Month<2.5 Then Year=C-4715 Endif Print " >> Date of Opposition = ";Month;"/";Day_of_month;"/";Year Return ' ' Procedure for a bell sound!!! ' Procedure Bell For Y99=1 To 2 Sound 1,15,1,7 Wave 1,1,9,15000,100 Next Y99 Return ' Procedure Any_key Repeat Z$=Inkey$ If Mousek<>0 Z$="" Endif Until Z$<>"" Return