NOVICE

19th May 2008, 03:36

Hi All,

This may sound simple to all you experienced Celestial types but to somebody like me who was weaned on GPS/Chart Plotters its all Swahili.

Will be going to school next year to learn the "Art" of Celestial Nav and i can honestly say i am pretty keen to do so, but i would like some idea of what the instructor is talking about before i go into class so have bought a few books on the subject, two of them are the 2008 Nautical Almanac and the latest edition of Nories Nautical Tables.

A friend of mine suggested i tackle a "Compass Error by Amplitude" to say i am stuck is putting it mildly......(Cloud) while i can get as far as finding the Declination from the Almanac and apply the "d corr" after that im stumped.

I would like to able to solve this two ways, one is using the formula....

Sin Amplitude = Sin Declination/Cos Latitude

...but i have no idea how to input this into a Sci Calculator (which buttons to push??) I realise there is more to it and i have the proforma for this.

The second way is through the Almanac/Norries route. The same friend gave me an worked example of a compleated proforma for a Sun Rise as follows.....

Position: 21 36,S 114 36,E

Time: 2300 GMT

Ships Compass Magnetic: 047

Gyro: 047

Object Sun rise bearing: 065

Local Variation: 1/2 degree East

Instructions:

1. Go to Almanac with date and time and get declination. Dec = 23 26.3

2. Go to Nories and look up True Amplitudes using declination. AMP = 25.6

3. Therefore 90-25.6 = 64.4. Closest 1/2 degree = 64.5

4. True Bearing = 64.5 degrees.

I have no trouble applying the corrections with this, the problem is where do i find the TRUE AMPLITUDES in Nories, what pages??

I should point out that the date on the above example was 20/6/01 so it would have been a 2001 Almanac used.

Well that will do for a start, no doubt i will have more for you later, might be a good idea for a new thread "How to: Celestial Navigation", just a thought.

Any help will be greatly appreciated...

John

This may sound simple to all you experienced Celestial types but to somebody like me who was weaned on GPS/Chart Plotters its all Swahili.

Will be going to school next year to learn the "Art" of Celestial Nav and i can honestly say i am pretty keen to do so, but i would like some idea of what the instructor is talking about before i go into class so have bought a few books on the subject, two of them are the 2008 Nautical Almanac and the latest edition of Nories Nautical Tables.

A friend of mine suggested i tackle a "Compass Error by Amplitude" to say i am stuck is putting it mildly......(Cloud) while i can get as far as finding the Declination from the Almanac and apply the "d corr" after that im stumped.

I would like to able to solve this two ways, one is using the formula....

Sin Amplitude = Sin Declination/Cos Latitude

...but i have no idea how to input this into a Sci Calculator (which buttons to push??) I realise there is more to it and i have the proforma for this.

The second way is through the Almanac/Norries route. The same friend gave me an worked example of a compleated proforma for a Sun Rise as follows.....

Position: 21 36,S 114 36,E

Time: 2300 GMT

Ships Compass Magnetic: 047

Gyro: 047

Object Sun rise bearing: 065

Local Variation: 1/2 degree East

Instructions:

1. Go to Almanac with date and time and get declination. Dec = 23 26.3

2. Go to Nories and look up True Amplitudes using declination. AMP = 25.6

3. Therefore 90-25.6 = 64.4. Closest 1/2 degree = 64.5

4. True Bearing = 64.5 degrees.

I have no trouble applying the corrections with this, the problem is where do i find the TRUE AMPLITUDES in Nories, what pages??

I should point out that the date on the above example was 20/6/01 so it would have been a 2001 Almanac used.

Well that will do for a start, no doubt i will have more for you later, might be a good idea for a new thread "How to: Celestial Navigation", just a thought.

Any help will be greatly appreciated...

John