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1860 Nov 20 Tuesday

That I may have the actual figures before me for reference, I make record of the Semi-diurnal & Seminocturnal [[?trackes]] of the rising & setting of the sun for this day in this latitude.  Table IX of "Bowditch's" Navigator does not extend beyond Latitude 60° - & in Declination but to 23°-28'.  Again - said table is calculated for the true sun's center when in the horizon no allowance having made for Refraction or Parallax.  To said table of course, equation of time has to be applied.  It is strange to me no direct information is given in "Bowditch" by which we can learn on what basis said table was constructed, or how to perform sums giving the actual clock time of the rising & setting of the sun - its upper limb as well as centre or that it was not extended up to 90°.  But Perseverance, has I think, allowed me to conquer.  I now understand on what basis said table was constructed & furthermore, can extend it up to lat. 90°. In truth, I have no occasion to use Table IX finding it better to dispense with it, performing all sums, through and through, on elements of the sum itself.  Today, Nov 20th 1860 in this Harbor
Latitude 62°-51'-05" N.
[[symbol: Sun]]'s Nov 20/60 Declination 19-49-40 S.
Nov 20/60 Equation subtraction = 14m-05s

At what Time from App Time (Mean time) Sun-rise & set - Length of day and night?
(The upper limb of the Sun 1st appearance & the upper limbs of the last appearance)

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1860 Nov 20

    90°-00'-00"
Lat 62 51-05 N
    ----------
    27°-08'-55" Co. Latitude
    (A)

90-00-00
[[symbol: Sun]]'s Dec. - 19-49-40 S. 
Polar Dist 109-49-40
(B)

Sun's Semi Nov 20 1860 diameter = | 16'-14"
Sun's Alt. 0° - Parallax | -09
[[symbol: Sun]]'s Apparent Alt. 0°-0' - Refraction | 33-00
(C) | +49'-23"

(C) | 90°-00'-00"
[[symbol: Sun]]'s Ref. Par. & Semi Diam. | +49-23
Zenith Distance | 90-49-23

Co. Latitude (A) |  27-08-55 | Cosecant |  .34075
Polar Distance (B) | 109-49-40 | Cosecant |  .02654
Sum | 227-47-58
Half Sum | 113-53-59 | Sine | 9.96102
Zenith Dist. | 90-49-23
Remainder | 23-04-36 | Sine | 9.59324
- | - | Sum | 2)19.92155
- | - | Half Sum, Cosine | 9.96077 which corresponds to h8-m48-s6 & AM 3-11-54 PM Apparent Time

Apparent Time (D) | h8-m48-s6 AM
Nov 20th Equation, subtractive | 14-5
Sun Rise 1st appearance [[symbol: Sun]]'s upper Limb = | 8-34-1 = Sun's Mean (or Clock) Time

Sun Set Last appearance [[symbol: Sun]]'s upper limb = | 3-25-59 = [[symbol: Sun]]'s Mean (or Clock) Time
- | 12-00-00

Length of night | h17-m08-s02 = (Night)
Length of Day | 6-51-58 = (Day)
- | 24-00-00

In above correct Sun-set as the [[underlined]] upper [[/underlined]] limb (not center) has been the basis of day - the day is much longer as Sun's diam. refrac & S. make it - of course night must have its proper corresponding length of time.  Hall