T A T A. Starpath form a = Zn = a - Lat = a - Lon = a = Zn = + - a - Lat = a - Lon = Copyright, 2003 Starpath School of Navigation

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1 tarpath fm 0 W h m s ate boy Hs WE D W E Lat Lon GM h m s GM ate / LO label log HE ft inex off on DI Ha GH hr. v planets H hr GH m.s. H v GH alon WE eg alat 00 W / 60 E 5 stars, planets tens units s. tab. ub. 9 ub. 9 upper lower s aitional altitue, mars, venus altitue all sights upper limb subtract 0 6 n = a Lat = a Lon = th Latitues greater than n = less than n = 60 outh Latitues greater than n = 80 less than n = 80 W h m s ate boy Hs WE D W E Lat Lon GM h m s GM ate / LO label log HE ft inex off on DI Ha GH hr. v planets H hr GH m.s. H v GH alon WE eg alat 00 W / 60 E 5 stars, planets tens units s. tab. ub. 9 ub. 9 upper lower s aitional altitue, mars, venus altitue all sights upper limb subtract 0 6 n = a Lat = a Lon = Copyright, 00 tarpath chool of avigation

2 Wkfm f O ight Reuction ables inclue in the autical lmanac bar top means roune value rouns up op ies Latitue R able R able H H lination D B D B sign B = sign if = 0 to 90 if = 9 to 69 if = 70 to 60 if = 0 to 90 if = 90 to 80 ux ux sign as = 0 to 59 if = 0 to 59 if = 0 to 9 = C C =. Lat. Lat to to n = ht Instructions In row, rec assume Lat,, an (D). Mark the signs of D, B, an. In row, with Lat an, enter ight Reuction (R) able an rec, B, an. D an B to get, an rec it in row. Copy to row an mark the sign of C. 5 Roun off to nearest whole egree an rec it as bar in row. 6 Mark the signs of an C in rows an. 7 Roun off to nearest whole egree an rec it as bar in row. 0 With an bar, enter uxiliary able (ux) an rec C in row. With an bar, enter ux table an rec C in row. C an C to H to get. an to get. Copy to space below it, rouning to nearest egree. Drop us sign if present. Convert to n by chosing appropriate sign next to. 5 Rec below ; take their ifference an rec it as a with the proper label. 8 With bar an bar, enter R table an rec H,, an in row. 9 Roun off an to nearest whole egrees an rec them as as bar an bar in rows an. Copyright, 00 tarpath chool of avigation

3 Using the O ables otes: () his proceure is the as presente in the lmanac, except f a change in notation explaine below () In the wkfm, row numbers are marke with white letters in black boxes. () Hs below above 87, see special instructions at the en. () the angle notation use in the fm is illustrate below: X = 5 8 an angle X = 5 egrees part of X X = 8 utes part of X X egree. = 6 X roune to the nearest whole tep. In the top lines of row, rec assume Latitue,, an lination (egrees in D; utes in D ). Circle the sign ( ) of D accing to ame Contrary name mark out the sign that oes not apply. tep. rom the rules besie the box, etere the sign of B an (epens on ) an circle these signs in row of the wk fm. B an have the sign. tep. With L an, enter the main ight Reuction (R) able an rec, B, an in the spaces provie in row, separating egrees an utes parts. Lat is foun at the top of the R tables; on either sie. ote the reer of this arrangement at the top left of the fm. his applies to all table entries. tep. Copy to row an circle the sign of C accing to the size of. tep 5. Roun off to the nearest whole egree an rec it as bar in row. tep 6. D an B algebraically to get, an rec it in the space provie in row. tep 7. rom the size of an the notes provie, etere the signs of an C an circle them in rows an. tep 8. Roun off to the nearest whole egree an rec it as bar in row. tep 9. With bar an bar, enter R table an rec H,, an into the spaces provie in row. tep 0. Roun off an to nearest whole egrees an rec them as as bar an bar in rows an. tep. With an bar, enter the uxiliary able (ux) an rec C in row. he ux table is at the en of the R table. tep. With an bar, enter the uxiliary able an rec C in row. tep. pply the crrections C an C (with their apapropriate signs) to H to get an rec it in the space provie. tep. Combine an (with their appropriate signs) to get an rec it in the space provie. he result can be negative positive (epening on the signs of an ), but this resulting sign is to be igne is to be treate as a positive number when later converting it to n. tep 5. Rec in the space provie below, then take their ifference an rec it as "a" in the space provie. Mark the proper label of the avalue using the rule if is greater than, then the label is "," otherwise it is "." tep 6. Convert to n using the traitional rules locate below the box f, an rec the result in the space provie. tep 7. lot the LO using the avalue, its label, an n Lowaltitue ights (Hs below so) Hs values below so (sights that are usually only taken in esperation when other sights are not available),,, both can be negative. In these cases, the Hs to conversion must be one carefully, as signs can change as crections are applie. lso, the above proceure must be moifie as follows: in tep 6 if is negative (can only happen f very low sights), treat it as positive until the final is etere in tep. n in tep 9, change to 80 (remembering that the iginal has a sign). In tep, if was negative, change to negative. Highaltitue ights (Hs above 87 so) very high sights, the stanar plotting proceure of intersecting two straight LOs oes not provie a reliable fix, because these lines are no longer goo approximations to the circles of position measure with the sextant. high sights, it is best to plot the G an then swing an arc from this point, using a raius equal to the zenith istance (90 ). his arc is then a section of your circle of position. It is ifficult to estimate the errs cause by neglecting this proceure since they epen on the heights of all sights use f the fix. In any event, when a fix is mae from ata incluing a high sight, it is best to check this effect. lso, our preliary stuy shows that the O type of sight reuction table oes not provie consistently accurate n values f very high sights. We have not analyze this effect in etail. We have foun no n problems f heights below 87. Copyright, 00 tarpath chool of avigation

4 Wkfm f O ight Reuction ables inclue in the autical lmanac op ies Latitue bar top means roune value rouns up ux O Example # rcturus R able R able ux sign as = 0 to 59 if = 0 to 59 if = 0 to 9 = 7 7 H H lination 9 D 8 B C C n = D B 0 to to 60 sign B = sign if = 0 to 90 if = 9 to 69 if = 70 to 60 if = 0 to 90 if = 90 to 80 =. Lat. Lat Exact is = 9.7 n= 78.6 op ies Latitue bar top means roune value rouns up ux O Example # ltair R able R able ux sign as = 0 to 59 if = 0 to 59 if = 0 to 9 = H H C C lination 8 D 9 B n = D B 0 to to 60 sign B = sign if = 0 to 90 if = 9 to 69 if = 70 to 60 if = 0 to 90 if = 90 to 80 =. Lat. Lat Exact is = 5 8. n= 78. Copyright, 00 tarpath chool of avigation

5 tarpath fm 06 op ies Latitue R able lination D B D B sign B = sign if = 0 to 90 if = 9 to 69 if = 70 to 60 bar top means roune value rouns up R able H H if = 0 to 90 if = 90 to 80 ux ux sign as = 0 to 59 if = 0 to 59 if = 0 to 9 = C C =. Lat. Lat to to n = op ies Latitue R able lination D B D B sign B = sign if = 0 to 90 if = 9 to 69 if = 70 to 60 bar top means roune value rouns up R able H H if = 0 to 90 if = 90 to 80 ux ux sign as = 0 to 59 if = 0 to 59 if = 0 to 9 = C C =. Lat. Lat to to n = Copyright, 00 tarpath chool of avigation

6 tarpath fm 07 tep Crect Hs to get Rec Maximum extant Height (Hs = peak height of the sun at noon), an mark limb Lower Upper Hs Rec Inex Crection (mark sign if off, if on) Rec eye height (HE) an Look up Dip Crection on the righthan sie of able, front of the lmanac (8 in notes) HE (ft) (crection epens on HE) um the above three numbers to get pparent Height IC Dip Ha Off On 5 Look up altitue crection on lefthan sie of able, front of the lmanac (8 in notes) (crection epens on Ha, Limb, an month) (mark sign f lower limb, f upper limb) lt 6 um the above two numbers to get Observe Height tep Detere the enith Distance Rec from tep, above, an then subtract it from 90 to get the zenith istance enith istance z tep Use the lmanac to in uns lination GM ate = Rec the ate an GM of the sight (the time the sun reache its peak height) GM (hr) = GM () = urn to the aily page of the lmanac f the ate of the sight, an fin the suns eclination (ec) f the hour of the sight (line ) an rec it here. (hr) Rec the value from the bottom of the ec column in the lmanac. Mark the signs of the value an cr if the ec f the next hour is larger, if it is smaller. value = cr = urn to the Increments an Crections pages at the back of the lmanac (9 to, in the notes) an fin the utes table f the GM utes (line ). On the righthan sie of the ouble line in the table, fin the cr cresponing to the value of line 5 lination = pply the cr to the ec(hr) an rec it above. tep in Latitue from enith Distance an lination lination enith istance Rec Latitue to use as a guie, an then take the sum ifference of zenith istance an eclination to fin your true Latitute at L. Copyright, 00 tarpath chool of avigation enith istance lination Latitue =