Generated by PyAlmanac
Author:
EnnoRodegerdtsDecember 1, 2014
downloaded from:
TheNauticalAlmanac.com
Disclaimer: These are computer generated tables. Use on your own risk. The accuracy has been checked as good as possible but can not be guaranteed. This means, if you get lost on the oceans because of errors in this publication I can not be held liable. or security rele!ant applications you should buy an official !ersion of the nautical almanac.
The Nautical Almanac ##$
Celestial Navigation
useful Formulas
About Calculators
The Casio
fx300ES Plus
is an inexpensive calculator at about 11 USD. It features
natural input
soyou enter a formula just as it would be written on paper. nterin! de!rees minutes and seconds isvery simple. The Casio
fx300ES Plus
has # memory locations and you can review many of theprevious entries you ma$e usin! a special $ey on the calculator.
Determine Hc using a calculatorThe formula
%c & asin'sin(
Declination
)*sin(
Latitude
) + cos(
Latitude
)*cos(
Declination
)*cos(
LHA
),
As it would be entered into the Casio calculator
Sin1(Sin(
Ap Latitude
) x Sin(
Declination
) + Cos(
Ap Latitude)
x Cos(
Declination
) x Cos(
LHA
)
Declination
is the declination of the Celestial body youre observin!. /hen the heavenly bodys declination is
Contrary name
to your 0p atitude enter a ne!ative si!n before it.
Latitude
is the atitude where you are thin$ you are or where you would li$e to determine %c for.Typically youll be usin! an
Assumed position Latitude
or
Ap Latitude
as its called.
In Western Longitudes
LHA
is the ocal %our 0n!le which is derived from subtractin! your whole number value of on!itude (0ssumed or otherwise) from the whole number value of
GHA
(2reenwich %our 0n!le).
In astern Longitudes
LHA
, i
n
Eastern Longitudes,
is determined by roundin! up the 2%0 3!ure to the next hi!hestwhole de!ree 3!ure then addin! the D4. on!itude to 2%0 to obtain %0. 5nly add the wholede!ree D4. on!itude 3!ure to the rounded up whole de!ree 2%0 3!ure. If the resultin! %03!ure is !reater than 6789 then subtract 6789 from the 3!ure to obtain the %0.
Wh! would !ou want to determine Hc using a calculator
Its faster than loo$in! up in :ub. ;o. <=# and :ub. ;o. <<# hi!hly accurate and you dont need alot of printed out pa!es of atitudes from :ub. ;o. <=# and :ub. ;o. <<#. :ub. ;o. <=# >ol. < ? 6dont cover any declination !reater than <# de!rees so youd have to use :ub. ;o. <<# which isextremely lar!e.
Celestial NavigationDetermine #
@ & acos'(sin(
Declination
) A sin(
Ap Latitude)
x sin(
Hc
))
B
(cos(
Ap Latitude
) x cos(
Hc
)),
As it would be entered into the Casio calculator$$$
Cos1((Sin(
Declination
) A Sin(
A%
Latitude
) x Sin(
Hc
))
B
(Cos(
A% Latitude
) x Cos(
Hc
)If the heavenly bodys declination is
Contrary name
to the 0p atitude enter a ne!ative si!n before it.
To obtain #n see the rules below for Northern and &outhern latitudes
.
Determine # independent of Hc
“L”
is latitude and
d”
is declination. /hen the heavenly bodys declination is
Contrary name
to your 0p atitude enter a ne!ative si!n before it.
As it would be entered into the Casio calculator$$$
@ & tan1 ((sin (
LHA
)
B
(cos(
A% latitude
) x tan(
declination
) A (sin(
A% latitude
) x cos(
LHA
))The si!n convention used in the calculation of this aimuth formula is as followsE
from
Bodit! C apter ## CALC$LA%&'(S A() C'(*E+S&'(S, pae 33
1) If latitude and declination are of contrary name declination is treated as a ne!ative FuantityG<) If the local hour an!le is !reater than 1H89 it is treated as a ne!ative Fuantity. If the aimuth an!le as calculated is ne!ative add 1H89 to obtain the desired value.
To obtain #n appl! the following rules
In Northern Latitudes
%0 !reater than 1H89....@n&@ %0 less than 1H89...........@n&6789 A @
In &outhern Latitudes
%0 !reater than 1H89....@n& 1H89 A @ %0 less than 1H89...........@n& 1H89 + @
Determine 'efraction
8.#7
B
Tan of (%a)
Determine Dip using feet
8.# x (SFuare 4oot of
.e
(%ei!ht of ye) in feet)
Determine Dip using meters
1.7 x (SFuare 4oot of
.e
(%ei!ht of eye) in meters )
fair inds///!lear sies and folloin seas
TheNauticalAlmanac$com
Explanation of The Nautical Almanac Daily Pages
1Date based on GMT/UT2Time based on GMT/UT (this is just integral hour only)3
Mer. pass
 meridian passage o !ries at the rime Meridian Green#i$h %&' Time gure is GMT/UT'G*!
v
$orre$tion and De$lination
d
$orre$tion' The amount to $orre$t
v
and
d
or is determined by theminutes and se$onds o time o the planet obser+ation and is ound in the
Increments and Corrections
pages o The ,auti$al !lmana$' The n$rements and .orre$tions pages are also no#n as
The Yellow Pages
as that0s the $olor o the paper in the U, published ,auti$al !lmana$'a
m
is the
magnitude
or brightness o the planet' ! bright planet #ill ha+e a
minus
sign beside the gure' !ainter planet #ill ha+e no sign beside its magnitude gure'
Stars

SHA
, Sidereal Hour Angle
4 and
Declination
' 5 stars are listed' Typi$ally4 only 6 stars are used orna+igational purposes in both ,orthern and outhern *emispheres'7
Mer. pass
 planet meridian passage time at the rime Meridian Green#i$h %&' Time gure is GMT/UT'6
SHA
planet
SHA
at the time o meridian passage at the rime Meridian Green#i$h %&' lanet *! is$al$ulated by subtra$ting planet G*! rom !ries G*!' Time gure is GMT/UT'8
Horizontal parallax
 or 9enus and Mars' 5Date based on GMT/UT1%Time based on GMT/UT (this is just integral hour only)11
SD
 emidiameter o the un' ne hal o the angular #idth o the un as obser+ed on earth' 12
 the amount the de$lination o the un $hanges per hour' there0s a minus sign beside the de$lination gure in the
Dec
$olumn then the un is in the outhern hemisphere'13The Moon0s G*!
v
$orre$tion' The amount to $orre$t the Moon0s G*! using
v
is determined by theminutes and se$onds o time o the Moon0s obser+ation and is ound in the
Increments and Corrections
pages o The ,auti$al !lmana$' The n$rements and .orre$tions pages are also no#n as
The Yellow Pages
as that0s the $olor o the paper in the U, published ,auti$al !lmana$'1
SD
 emidiameter o the Moon' ne hal o the angular #idth o the Moon4 as obser+ed on earth' 1The Moon0s de$lination
$orre$tion' t0s the amount o de$lination the Moon $hanges per hour' *o#e+erthe amount to $orre$t the Moon0s de$lination using
is determined by the minutes and se$onds o time o the Moon0s obser+ation and is ound in the
Increments and Corrections
pages o The ,auti$al !lmana$' The
$orre$tion is
algebraically
added' !n easy #ay to determine #hether to
add
or
subtract
the
$orre$tion ound in the
Increments and Corrections
pages
is by e:amining the Moon0s de$lination trend in The ,auti$al !lmana$' the de$linationis in$reasing (regardless o its sign ; or ) rom the integral hour o the obser+ation you made then add the
in$rement and in$rease the +alue o the de$lination' the de$lination is de$reasing (regardless o itssign ; or ) rom the integral hour o the obser+ation you made then subtra$t the
in$rement andde$rease the +alue o the de$lination' Mae sure to put the sign <ba$ on= the $orre$ted de$lination soyou no# #hi$h hemisphere the Moon0s in'The n$rements and .orre$tions pages are also no#n as
The Yellow Pages
as that0s the $olor o the paperin the U, published ,auti$al !lmana$'17
HP
 the angle bet#een t#o lines4 one rom the $enter o the Moon to the $enter o the >arth4 the otherrom the $enter o the Moon to the edge o the >arth' This angle is about 704 but it $hanges slightly romday to day as the distan$e to the Moon $hanges along its ellipti$al path around the >arth'
Source starpath.com
16
Sun E!n. of Time
 >?uation o Time is the di@eren$e bet#een GMT/UT and A!, at Green#i$h' Thegures listed are or GMT/UT at %%
h
and 12
h
' you loo at
Mer. Pass
just to the right o the
E!n. of Time
you0ll nd4 appro:imately4 #hen the un $rosses The rime Meridian (at Green#i$h)' The gures in the 12
h
$olumn indi$ate4 appro:imately4 ho# many minutes and se$onds are subtra$ted4 or added4 to 12 todetermine #hen Ao$al !pparent ,oon is at The rime Meridian' Bou $an $al$ulate4 appro:imately4 #henA!, is at your Aongitude by adding4 or subtra$ting the amount o time di@eren$e bet#een you and