
 Sight Reduction Worksheet for HO-211 Ageton Tables.

 "Ageton-Bayless Compact Sight Reduction Table", called A-BCSRT below.

40 (A-BCRST 1,2): t = smaller angle between observer and Body;
          then find A in A-BCSRT. 
          If Body W then t = LHA. 
          If Body E then t = 360 - LHA. 
          [ A(t) ]
41 (3-5): Dec Body from 18 round up or down to nearest minute, N or S;
          then find B and A in A-BCSRT for that number. 
          [ B(Dec) ]
42 (6-9): Add A in 40 and B in 41 to get A in 42. 
          Find B in the table closest to A, enter in both B(-) and B spaces. 
          [ A(R) = A(t) + B(Dec) ] [ B(R)]
43 (10): Subtract B(-) in 42 from A in 41 to get A in 43.
         [ A(K) = A(Dec) - B(R) ]
44 (11): Find K in the table corresponding to A in 43
         Give K the same name N or S as Dec in 41: 
         If t > 90o then K is too. 
         If t < 90o then K is too. 
         Check whether K is between 82o and 98o using Laidlaw's graph. If so,
         then use Sadler's salvage technique. 
         [ K ]
45 (12): Enter AP L in nearest minute of arc, N or S, from 3 or 45. (Can use
         L of another position, but the advantage of the Ageton-Bayless Compact
         Sight Reduction Table is that you can use the AP latitude, same as
         when using a calculator or computer.) 
         [ L ]
46 (13): K~L. If 44 and 45 are:
         Contrary name, then add them. 
         Same name, then subtract them. 
         [ K~L ]
47 (15,16): Hc: Add B in 42 to B in 46 to get A in 47. 
         From table find B corresponding to A. 
         At same time note Hc for 47: heading row (degrees) and left or right
         column (minutes). If A is in the left side of the data column, then
         use the top row of the heading row for degrees, and the left column
         for minutes. 
         [ A(Hc) = B(K~L) + B(R) ]
48 (17): Hc from the table lookup done in 47.
         [ Hc ]
49 (20): Subtract B in 47 from A in 42 to get 49. If it is a negative number
         then use zero (occurs when Body is on prime vertical and Z = 90o). 
         [ A(Z) = A(R) - B(Hc) ]
50 (21): Look up Z in the table using A and enter in 50:
         Prefix from L and suffix from t. 
         If K in 44 (11) has same name as L, and K > L, then Z < 90o,
         otherwise Z > 90o. 
         [ Z ]
51 (22): Convert Z to Zn, nearest 1/10 degree (see A-BCSRT p. 12). Use the
         aids in center or bottom of SR-90: 
         Prefix from Latitude, suffix from t angle. 
         If Z is NE then Zn = Z. 
         If Z is NW then Zn = 360o - Z. 
         If Z is SE then Zn = 180o - Z. 
         If Z is SW then Zn = 180o + Z. 
         [ Zn ]
52 (18): Ho, rounded to nearest minute of arc:
         Using the Ageton-Bayless method, take the difference between
         48 (17) and 52 (18). 
         [ Ho - Hc ]
53 (19): Intercept "a" = Hc - Ho.
         (-) result then intercept Toward the Body; (+) Away. 
         HoMoTo: if Ho is more than Hc then the intercept is Toward. 
         Coast Guard Academy (Computer Greater Away): if Hc > Ho then the
         intercept is Away


from:www.jimthompson.net/boating/CelestialNav/CelestNotes/SightReduction.htm

