magnetic deviation
Submitted: Tuesday, Apr 03, 2007 at 10:51
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Peter from York 4x4
Hi can anyone tell me the current magnetic deviation for Western Australia please
Reply By: equinox - Tuesday, Apr 03, 2007 at 11:27
Tuesday, Apr 03, 2007 at 11:27
Try this site here.
AnswerID:
231404
Reply By: Shaker - Tuesday, Apr 03, 2007 at 11:34
Tuesday, Apr 03, 2007 at 11:34
I think you may have your teminology mixed up .......
Deviation is the error in reading a bearing from the compass caused by the magnetic influence of some nearby object.
Variation/Declination in
Perth is approximately 1.5 degrees West, so True North is approximately 1.5 degrees east of your compass reading.
AnswerID:
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Follow Up By: Peter from York 4x4- Tuesday, Apr 03, 2007 at 11:43
Tuesday, Apr 03, 2007 at 11:43
thanks, I knew what I ment to say so i' m glad you knew what I ment, not what I asked to ment to say hahahaha
PS thanks for the answer it's what I was after
Peter
FollowupID:
492325
Follow Up By: equinox - Tuesday, Apr 03, 2007 at 16:08
Tuesday, Apr 03, 2007 at 16:08
In the website I listed above it shows
Perth being 5.49 degrees. Meaning true north is 5.49 degress west of your compass reading.
So I disagree with Shaker by 6.99 degrees.
I will stand corrected of course.
FollowupID:
492377
Reply By: Member - Rotord - Tuesday, Apr 03, 2007 at 12:22
Tuesday, Apr 03, 2007 at 12:22
Looking at my map of
Port Hedland , variation is 1.9 degrees east , therefore , magnetic is least .
AnswerID:
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Follow Up By: macca172 - Tuesday, Apr 03, 2007 at 19:39
Tuesday, Apr 03, 2007 at 19:39
East is least, west is best!
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Follow Up By: djm67 - Tuesday, Apr 03, 2007 at 22:19
Tuesday, Apr 03, 2007 at 22:19
Also remember to
check what year that mag variation was correct for, and how much it moves, and in what direction, for each given year/period thereafter (e.g. the map should say something like 'reading is correct for 1995 and moves Easterly by 1 degree every 2 years')
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Reply By: kingswoodwagon - Tuesday, Apr 03, 2007 at 13:23
Tuesday, Apr 03, 2007 at 13:23
Peter,
the magnetic declination used 'in the field' is usually specific to that of the map or
grid (in the case of surveying). assuming your trying to use the compass in conjunction with a particular map.
declination for that purpose is the difference between Magnetic North and
Grid north.
all maps should state their declination (usually near
north point or in title box)
a typical calm map in the south west of W.A. (DOLA -CALM would have a declination of 3-4 degrees. the NATMAP maps are closer to 2.5 degrees.
When converting a map bearing to a compass bearing, west is best (add declination), and east is least (subtract declination).
hope this helps
roopaw@westnet.com.au
AnswerID:
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Reply By: Baldrick - Tuesday, Apr 03, 2007 at 14:53
Tuesday, Apr 03, 2007 at 14:53
Varies according to where you are as
well, not everywhere in WA will be the same.
The largest declination I have experienced (not in WA) is 87 deg!
AnswerID:
231439
Follow Up By: Member - Kiwi Kia - Tuesday, Apr 03, 2007 at 15:42
Tuesday, Apr 03, 2007 at 15:42
Hi Baldrick, could you enlighten me as to where you were when you had 87 degree variation ? High lat. Canada maybe ?
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Follow Up By: Baldrick - Wednesday, Apr 04, 2007 at 13:01
Wednesday, Apr 04, 2007 at 13:01
Hi Kiwi Kia,
high latitude is right, but the other way - Davis, Antarctica. #8->
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Follow Up By: Member - Kiwi Kia - Wednesday, Apr 04, 2007 at 13:08
Wednesday, Apr 04, 2007 at 13:08
Ahh, Did you actually try using a compass down there? The needle would probably try and point straight down :-))
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Follow Up By: Baldrick - Wednesday, Apr 04, 2007 at 18:27
Wednesday, Apr 04, 2007 at 18:27
Actually we were far enough fom the magnetic pole that compasses still worked ok, it's just that the magnetic pole was nearly due east!
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492632
Reply By: Peter from York 4x4- Tuesday, Apr 03, 2007 at 16:43
Tuesday, Apr 03, 2007 at 16:43
Hi and thanks for all input , I have a new digital compass to be used in WA the instructions list the Eastern states as an average of 10.8 deg East , as I will only be using it in and around southern WA I was looking for an average declination to enter in the compass
Peter
AnswerID:
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Follow Up By: Member - Andrew (QLD) - Tuesday, Apr 03, 2007 at 18:17
Tuesday, Apr 03, 2007 at 18:17
An image to help visualise magnetic variation for Australia:
Andrew
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Follow Up By: howie - Wednesday, Apr 04, 2007 at 14:36
Wednesday, Apr 04, 2007 at 14:36
the map above gives a good idea of the variations.
if you want the exact variation at your position you can refer to a W.A.C. chart
from the aviation field.(world aero chart)
i only bother with variation when flying.
you would be hard pushed getting totally lost in SW w.a. by car!
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Follow Up By: Peter from York 4x4- Wednesday, Apr 04, 2007 at 15:00
Wednesday, Apr 04, 2007 at 15:00
Thanks howie ,it's not for in the car I have oziexplorer for that this is for trailbike riding in larger state forrests etc
Peter
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