Navigation Tutorial
Appendix A - Compasses with a Declination Adjustment
All content copyright © Ashley Burke 2014. Not to be copied, duplicated or used for any purpose without permission.
Navigation Tutorial Appendix A - Compasses with a Declination Adjustment
All content copyright © Ashley Burke 2014. Not to be copied, duplicated or used for any purpose without permission. |
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Navigation course by Ashley Burke
12. Compasses With a Declination Adjustment
Some compasses, such as the Suunto M-3, have a separate declination scale on the inside of the compass dial that can be set to compensate for the difference between grid north and magnetic north. Using a little screw on the back of the compass you can set this to the grid to magnetic angle. For example in NSW Australia you would set this to 12 degrees east of North. Then, you don't need to worry about adding or subtracting the grid to magnetic angle each time you set your compass. This is already done for you. Everything else is unchanged, it's just that Step 3 in Section 8.3 and Step 3 in Section 9.3 can be omitted.
A WORD OF CAUTION
Relying on the declination scale on your compass rather than adding and subtracting manually means the declination scale must be set correctly first, otherwise you will be out by 12 degrees or even 24 degrees! Be very careful before relying on the compass declination scale. I always prefer to add and subtract the magnetic angle manually. That way I am sure that it gets done and I am not relying on "set and forget" mentality to do the work for you. When set correctly it works. But when set incorrectly or not at all, you could have problems if you ignore the grid to magnetic conversion.
Thank You
Ok, that's all you're going to learn sitting in front of a computer. If you want to learn more, you'll need to get out into the bush and do it for yourself.
I have put together this tutorial in the hope that the skills of navigation will not be lost to new technologies such as satellite navigation systems and GPS. If you have any feedback on how I can improve this web page please email me. If you want to come along on a trip, click here for more information.
The End
copyright © Ashley Burke 2008
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Web page created 23 Dec 2014, last updated 23 Dec 2014. All content copyright © Ashley Burke 2014. Not to be copied, duplicated or used for any purpose without permission. |
