Higher National Unit Specification

General information for centres

Unit title: Celestial Navigation

Unit code: D77R 35

Unit purpose: This Unit is about using a sextant and chronometer to obtain the time of observation and the observed altitude of celestial bodies. It is also about calculating a ship’s position by celestial observations. It is primarily aimed at candidates who intend to seek sea-going employment as a Merchant Navy Deck Officer. However it could also be studied by someone with an interest in the subject area.

On completion of this Unit the candidate should be able to:

1. Use instruments and apply corrections to obtain Observed Altitude and UTC 2. Calculate, from observations of celestial bodies, the direction of a position line, a point through which it passes and the error of the compass 3. Determine the ship’s position by celestial observations

Credit value: 1.5 HN Credits at SCQF level 8: (12 SCQF credit points at SCQF level 8)

SCQF (the Scottish Credit and Qualifications Framework) brings Scottish qualifications into a single framework of 12 levels ranging from SQA Access 1 to doctorates. The SCQF includes degrees; HNC/Ds; SQA National Qualifications; and SVQs. Each SQA Unit is allocated a number of SCQF credit points at a specific level. 1 SCQF point = 10 hours of learning. HN candidates are normally expected to input a further number of hours, matched to the credit value of the Unit, of non-contact time or candidate-led effort to consolidate and reinforce learning.

Recommended prior knowledge and skills: Access to this Unit is at the discretion of the centre. However it would be beneficial if candidates had achieved the competence required in the HN units D77S 34 Chartwork and D77T 34 Tides and Sailings. In addition, it is recommended that candidates have a good grounding in spherical trigonometry before undertaking the Unit by successfully completing the Marine Induction Course associated with the HNC/D Nautical Science.

Core skills: There may be opportunities to gather evidence towards core skills in this Unit, although there is no automatic certification of core skills or core skills components.

Context for delivery: This Unit is included in the framework of the HNC/D Nautical Science. It is recommended that it should be taught and assessed within the subject area of the group award to which it contributes.

HN Unit D77R 35: Celestial Navigation 1 General information for centres (cont)

Assessment: Assessment will be on a sample basis. Outcome 1 will be assessed by practical demonstration supplemented by oral questioning if necessary. Outcomes 2 and 3 can be combined for assessment purposes and assessed by written questions under supervised conditions.

HN Unit D77R 35: Celestial Navigation 2 Higher National Unit specification: statement of standards

Unit title: Celestial Navigation

Unit code: D77R 35

The sections of the Unit stating the Outcomes, knowledge and/or skills, and evidence requirements are mandatory.

Where evidence for Outcomes is assessed on a sample basis, the whole of the content listed in the knowledge and/or skills section must be taught and available for assessment. Candidates should not know in advance the items on which they will be assessed and different items should be sampled on each assessment occasion.

Outcome 1

Use instruments and apply corrections to obtain Observed Altitude and UTC

Knowledge and/or skills • Identifying the parts of a sextant • Finding sextant errors and making the appropriate adjustments or corrections • Using the sextant to accurately measure angles and the altitude of the Sun, stars and planets • Use and care of the chronometer • Finding the value of the chronometer error by means of time signals • Finding the UTC of an observation

Evidence requirements Candidates will need evidence to demonstrate their knowledge and/or skills by showing that they can: • check correctly for sextant errors and make adjustments • use a sextant to accurately measure angles and the altitude of celestial bodies • read the chronometer to accurately find the time of an observation • use and care correctly for the chronometer

Assessment guidelines Outcome 1 will be assessed on a sample basis by practical demonstration on the use of the sextant and chronometer. Where performance evidence is insufficient, this could be supplemented by oral questioning to ensure the required evidence is obtained.

HN Unit D77R 35: Celestial Navigation 3 Higher National Unit specification: statement of standards (cont)

Unit title: Celestial Navigation

Outcome 2

Calculate, from observations of celestial bodies, the direction of a position line, a point through which it passes and the error of the compass

Knowledge and/or skills • Using the Nautical Almanac to find the GHA, LHA and declination of Sun, stars and planets • Obtaining UTC, LMT, standard time and Zone Time • Using the Nautical Almanac altitude correction tables to obtain true altitude • Using the Nautical Almanac to find the time for star observations • Using the Nautical Almanac to find the time of meridian passage for the Sun • Applying TZD to declination to obtain latitude • Correcting the true altitude of Polaris to obtain a position line and latitude • Using the Marc St. Hilaire method by both calculation and short method tables to obtain a position line and a point through which it passes • Plotting position lines • Calculating compass error and deviation by means of azimuths of celestial bodies and amplitude of the Sun • Calculating compass error and deviation by Polaris

Evidence Requirements Candidates will need evidence to demonstrate their knowledge by showing that they can accurately calculate: • from an observation of the Sun when on the meridian, the latitude • from an observation of the Sun , star or planet when out of the meridian and using the Marc St. Hilaire method, the direction of a position line and a point through which it passes • from an observation of Polaris, the direction of the position line and a position through which it passes • the compass error and deviation by means of azimuth of celestial bodies and amplitude of the sun

Assessment guidelines It is suggested that this Outcome is assessed on a sample basis using written questions under supervised conditions with reference to the Nautical Almanac, nautical tables, charts and diagrams. However each assessment should feature a latitude by meridian altitude of either the sun or a latitude by polaris. It should also feature an out of the meridian observation of either the sun, a star or a planet and finding the error of the compass. It is recommended that Outcome 2 be combined with Outcome 3 for assessment purposes.

HN Unit D77R 35: Celestial Navigation 4 Higher National Unit specification: statement of standards (cont)

Unit title: Celestial Navigation

Outcome 3

Determine the ship's position by celestial observations

Knowledge and/or skills • Position fixing by simultaneous observations and plotting position lines • Position fixing with a run between sights • Plotting transferred position lines • Selecting suitable bodies for observation • Use of star charts or short method tables to pre-compute the approximate altitudes and azimuths of stars to determine availability for position fixing • Use of NP 323 Starfinder and Identifier • Identifying star magnitudes and constellations.

Evidence requirements Candidates will need evidence to demonstrate their knowledge by showing that they can interpret information from the Nautical Almanac and charts expressed in a variety of graphical, tabular and diagramatical forms, to: • determine the approximate altitude and azimuth of appropriate celestial bodies for position fixing • accurately determine the position from simultaneous observations • accurately determine the position involving a run between observations

Assessment guidelines It is suggested that this Outcome is assessed on a sample basis using written questions under supervised conditions with reference to the Nautical Almanac, nautical tables, charts and diagrams. However each assessment should test knowledge of a selection of observed celestial bodies as well as obtaining the ship’s position from either simultaneous observations or observations with a run in between. It is recommended that Outcome 2 be combined with Outcome 3 for assessment purposes.

HN Unit D77R 35: Celestial Navigation 5 Administrative Information

Unit code: D77R 35

Unit title: Celestial Navigation

Superclass category: RE

Date of publication: August 2001

Source: SQA

© Scottish Qualifications Authority 2001

This publication may be reproduced in whole or in part for educational purposes provided that no profit is derived from reproduction and that, if reproduced in part, the source is acknowledged.

Additional copies of this Unit specification can be purchased from the Scottish Qualifications Authority. The cost for each Unit specification is £2.50 (minimum order £5.00).

HN Unit D77R 35: Celestial Navigation 6 Higher National Unit specification: support notes Unit title: Celestial Navigation

This part of the Unit is offered as guidance. The support notes are not mandatory.

While the exact time allocated to this Unit is at the discretion of the centre, the notional design length is 60 hours.

Guidance on the content and context for this Unit

The content of this Unit forms part of the underpinning knowledge for the Level 3 SVQ Marine Vessel Operations and reflects the content of International Maritime Organisation’s Standards of Training Certification and Watchkeeping (STCW).

Guidance on the delivery of this Unit

Candidates would benefit from this Unit if they have completed the HN Units D77S 34 Chartwork and D77T 34 Tides and Sailings.

The concept of the celestial sphere, apparent annual and daily motion, together with details of individual altitude corrections are no longer considered necessary knowledge to fix a ship's position by celestial observations. Reference to this would however give a better understanding of the use and format of data, increment and the total correction tables in the Nautical Almanac.

The use of the Marc St. Hilaire method to obtain a position line and a point through which it passes can be solved with the use of a non-programmable calculator. Candidates should also be shown how to use short method tables.

The knowledge and skills acquired in this Unit will be practised extensively at sea so that the experience gained can be utilised in the HN Unit D78F 35 Passage Planning which features in the later stages of the HND Nautical Science.

Open learning:

The preferred method of delivery is by attendance at college as the majority of candidates following this HND will be on a training programme comprising alternating periods at college and at sea, the sea periods being utilised to put into practice knowledge and skills acquired.

HN Unit D77R 35: Celestial Navigation 7 Higher National Unit specification: support notes (cont)

Special needs

This Unit specification is intended to ensure that there are no artificial barriers to learning or assessment. Special needs of individual candidates should be taken into account when planning learning experiences, selecting assessment instruments or considering special alternative Outcomes for Units. For information on these, please refer to the SQA document Guidance on Special Assessment and Certification Arrangements for Candidates with Special Needs and Candidates for whom English is an Additional Language (SQA, 2000).

HN Unit D77R 35: Celestial Navigation 8 General information for candidates:

Unit title: Celestial Navigation

This Unit is about the ability to use a sextant and chronometer to obtain the time of observation, the observed altitude of celestial bodies and to calculate the ship’s position from celestial observations.

On completion of this Unit you should be able to:

• Use instruments and apply corrections to obtain observed altitude and UTC • Calculate from observations of celestial bodies the direction of a position line, a point through which it passes and the error of the compass. • Determine the ship's position by celestial observations. . In order to achieve the above three Outcomes it will also be necessary for you to be familiar with the use and information contained in the Nautical Almanac and the solution of spherical triangles by means of a calculator or tables.

You will be assessed practically on your ability to use the sextant and chronometer. Your ability to fix the ship’s position from observations of the sun, stars and planets and to find the compass error by celestial observation will be assessed by means of a written assessment under supervised conditions with reference to the Nautical Almanac, nautical tables, charts and diagrams.

Acronyms

GHA Greenwich Hour Angle LHA Local Hour Angle LMT Local Mean Time NP Nautical Publication (UK Hydrographic Office) NP323 UK Hydrographic Office Star Finder and Identifier TZD True Zenith Distance UTC Coordinated Universal Time

HN Unit D77R 35: Celestial Navigation 9