true north
 

In setting up the anemometer I had to set it to magnetic north, being in
central fl. I know the difference is not much but having been employed at a
testing lab for over ten years I know "close enough is not a value" If
anyone could point me in the right direction it would be appreciated.--
John Popp
Deltona Fl.

true north
 

John Popp wrote:

In setting up the anemometer I had to set it to magnetic north, being in
central fl. I know the difference is not much but having been employed at a
testing lab for over ten years I know "close enough is not a value" If
anyone could point me in the right direction it would be appreciated.--

Any decent map will have the magnetic correction on it... usually a
small arrow and the number of degrees from TN.

--
John H

true north
 

John_H wrote:
John Popp wrote:

In setting up the anemometer I had to set it to magnetic north, being in
central fl. I know the difference is not much but having been employed at a
testing lab for over ten years I know "close enough is not a value" If
anyone could point me in the right direction it would be appreciated.--

Any decent map will have the magnetic correction on it... usually a
small arrow and the number of degrees from TN.

Isn't there a daily variation? And an annual one?

true north
 

Weatherlawyer wrote:

John_H wrote:

Any decent map will have the magnetic correction on it... usually a
small arrow and the number of degrees from TN.

Isn't there a daily variation? And an annual one?

Or by the decade for a significant change! :)

This one might help....
http://www.scoutingresources.org.uk/compass_magvar.html

A handheld GPS receiver should also do the job.

--
John H

true north
 

On Mon, 14 Aug 2006 11:21:03 -0400, "John Popp"
wrote:

In setting up the anemometer I had to set it to magnetic north, being in
central fl. I know the difference is not much but having been employed at a
testing lab for over ten years I know "close enough is not a value" If
anyone could point me in the right direction it would be appreciated.--
John---
Is there a yacht harbor, saling school, sales office, etc., near you.
Or an airport, or expecially a flight school or an avionics repair
facility. Among these, a gyrocompass repair shop is best. All of
these folks deal with this kind of stuff and out to be able to tell
you. So could a land surveyor.
The rule we used was
Can Dead Men Vote Twice or conversely
True Virgins Make Dull Company
i.e. C-D-M-V-T, or
Compass +/- Deviation = Magnetic +/- Variation = True
Variation is that difference caused by the earth's magnetic field. It
is readily determined or interpreted from a nautical chart, but any
yacht harbor office ought to know it, as should the folks along the
flight line.
Deviation is caused by the magnetic influence of surrounding
sturcture. A big problem on a steel ship, probably not for you, so I
would discount it.
See if you can determine the exact latitude and longitude of your
house (not such a hard problem. Your city assessor probably knows or
can find out. So would a surveyor.)
Then you can go he
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
These folks call variation magnetic declination. Same thing for your
purposes.
However, I venture a guess that your current set up is, in fact,
"close enough".

30 years at sea

true north
 

Bingo !!! I'll try the airports. I have done the tables in my sailing days,
but I was hoping someone knew off hand., besides I don't remember where my
parallel rule is so running from the rose would be a pain. Thanks guys, I
did read them all.--
John Popp
Deltona Fl.
"Roy Starrin" wrote in message
...
On Mon, 14 Aug 2006 11:21:03 -0400, "John Popp"
wrote:

In setting up the anemometer I had to set it to magnetic north, being in
central fl. I know the difference is not much but having been employed at
a
testing lab for over ten years I know "close enough is not a value" If
anyone could point me in the right direction it would be appreciated.--
John---
Is there a yacht harbor, saling school, sales office, etc., near you.
Or an airport, or expecially a flight school or an avionics repair
facility. Among these, a gyrocompass repair shop is best. All of
these folks deal with this kind of stuff and out to be able to tell
you. So could a land surveyor.
The rule we used was
Can Dead Men Vote Twice or conversely
True Virgins Make Dull Company
i.e. C-D-M-V-T, or
Compass +/- Deviation = Magnetic +/- Variation = True
Variation is that difference caused by the earth's magnetic field. It
is readily determined or interpreted from a nautical chart, but any
yacht harbor office ought to know it, as should the folks along the
flight line.
Deviation is caused by the magnetic influence of surrounding
sturcture. A big problem on a steel ship, probably not for you, so I
would discount it.
See if you can determine the exact latitude and longitude of your
house (not such a hard problem. Your city assessor probably knows or
can find out. So would a surveyor.)
Then you can go he
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
These folks call variation magnetic declination. Same thing for your
purposes.
However, I venture a guess that your current set up is, in fact,
"close enough".

30 years at sea

true north ps
 

lat28:53:55.018n long81:15:52.470w
--
John Popp
Deltona Fl.
"Roy Starrin" wrote in message
...
On Mon, 14 Aug 2006 11:21:03 -0400, "John Popp"
wrote:

In setting up the anemometer I had to set it to magnetic north, being in
central fl. I know the difference is not much but having been employed at
a
testing lab for over ten years I know "close enough is not a value" If
anyone could point me in the right direction it would be appreciated.--
John---
Is there a yacht harbor, saling school, sales office, etc., near you.
Or an airport, or expecially a flight school or an avionics repair
facility. Among these, a gyrocompass repair shop is best. All of
these folks deal with this kind of stuff and out to be able to tell
you. So could a land surveyor.
The rule we used was
Can Dead Men Vote Twice or conversely
True Virgins Make Dull Company
i.e. C-D-M-V-T, or
Compass +/- Deviation = Magnetic +/- Variation = True
Variation is that difference caused by the earth's magnetic field. It
is readily determined or interpreted from a nautical chart, but any
yacht harbor office ought to know it, as should the folks along the
flight line.
Deviation is caused by the magnetic influence of surrounding
sturcture. A big problem on a steel ship, probably not for you, so I
would discount it.
See if you can determine the exact latitude and longitude of your
house (not such a hard problem. Your city assessor probably knows or
can find out. So would a surveyor.)
Then you can go he
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declination.jsp
These folks call variation magnetic declination. Same thing for your
purposes.
However, I venture a guess that your current set up is, in fact,
"close enough".

30 years at sea

true north ps
 

On Thu, 17 Aug 2006 22:46:16 -0400, "John Popp"
wrote:

lat28:53:55.018n long81:15:52.470w

I came up with 5° 27' W changing by 0° 4' W/year

true north ps
 

I thank you, no doubt right on the money. I took the easy way out. the
mentiobn of airports reminded me of altitude, gyro setting before take off
sooo I tried the web (closest airport) flight service center yep there it
was 05w. The last time I was behind a yoke, there were no computers. Flight
calculators and slip sticks. Ain't technology great--
John Popp
Deltona Fl.
"Roy Starrin" wrote in message
...
On Thu, 17 Aug 2006 22:46:16 -0400, "John Popp"
wrote:

lat28:53:55.018n long81:15:52.470w

I came up with 5° 27' W changing by 0° 4' W/year