Maritime Celestial Logarithm Tables Mastery

Maritime Celestial Logarithm Tables Mastery: TWO EXERCISES TO CALCULATE THE ALTITUDE OF THE SUN (Hc)

Start with the Logarithme MAIN page — it forms the foundation of the “Logarithmic” menu and contains all related links. It will guide you back here when needed.

The five tables:

The five tables available for download

This section is an additional feature of my website. It’s important to note that I don’t recommend starting with this particular method.

Here, I introduce a well-established celestial navigation technique that involves utilizing logarithm tables.

To start learning celestial navigation, begin with the La Rochelle exercise, which covers all the fundamental concepts.

Celestial Logarithm Tables Mastery: SEE FIRST

the fully worked out example !

exercise 1

entries L D and P

The entries obtained in the first part of the worksheet are necessary to find the calculated altitude (Hc):

L = 19° 03′ N ( D.R. latitude)

D = 21°10′.5 S (Declination of the sun)

P = 7°21′.9 (NW) (polar angle)

(latitude North and sun in the West)

Maritime Celestial Logarithm Tables Mastery:

Step 1

To clarify see the four examples of same name and not same name

First, note the two entries obtained from the worksheet:

L = 19° 03′ N // D = 21°10′.5 S

L =

D =

__________________

(L ±D) =

Step 2

Now we need the three entries obtained from the worksheet:

L = 19° 03′ N // D = 21°10′.5 S

P = 7°21′.9 (NW)

1(T 1 ) LOG COS L =

2(T 1 ) LOG COS D =

3(T 2 ) VERSINE P =

_________________________+

LOG 2nd Term =

Step 3

First the entries: (L±D) obtained in step 1

The entry log 2nd term obtained in step 2 is then transformed to the natural 2nd term using Table 4 (logarithms of whole numbers).

Here is an example from Table 4 showing how to transform the logarithmic 2nd term into the natural 2nd term.

(T 3) COS (L ±D) =

(T4 ) Nat 2nd T =

__________________________⎼

SIN Hc =

Step 4

The entry sin Hc obtained in Step 3

(T 5) Hc =

Maritime Celestial Logarithm Tables Mastery:

The second exercise

entries L D and P

L = 31° 29′.5 N

D = 23° 18′.1 N

P = 32° 23′.8 NE

step 1

Here the two entries obtained from the worksheet:

L = 31° 29′.5 N; D = 23° 18′.1 N

L =

D =

__________________

(L ±D) =

In addition 4 examples of same name and not same name

Step 2

First the three entries obtained from the worksheet:

L = 31° 29′.5 N D = 23° 18′.1 N

P = 32° 23′.8 NE

1(T 1 ) LOG COS L =

2(T 1 ) LOG COS D =

3(T 2 ) LOG VERSINE P =

__________________________+

LOG 2nd Term =

Step 3

First the entries: (L±D) obtained in step 1

The entry log 2nd term obtained in step 2 is then transformed to the natural 2nd term using Table 4 (logarithms of whole numbers).

(T 3) COS (L ± D) =

(T4 ) Nat 2nd T =

__________________________−

SIN Hc =

Here is an example from Table 4 showing how to transform the logarithmic 2nd term into the natural 2nd term.

Step 4

The entry sin Hc obtained in Step 3

(T 5) Hc =

Maritime Celestial Logarithm Tables Mastery: short summary

In this course, you will find a total of four exercises from the logarithm tables, with the necessary table pages and solutions included.

Once you have gone through them and become familiar with them, you can test your skills on the seven remaining exercises. You need to purchase the PDF answer files in the store and they come with the full download version of the tables.

I printed these tables along with the azimuth tables using only one XL cartridge. You can also have them printed at your local print shop.

This is an exceptional tool — but it demands careful organization.