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Subject: [M]: Re: RE: Magenetic Declination web site.
From: Paul Luckas
Reply To: mapug@shore.net
Date: Tue Jul 03 23:05:08 2001
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Dave,
On the web site's output page, click on the "D" above the value you get =
for the magnetic declination. It will take you to a description of what =
it means, and how to use it.=20
In essence, the true bearing (the direction you want to point your =
telescope in, ie, true north in this case) is the magnetic bearing (the =
direction the compass is pointing) plus the magnetic declination which =
was computed for your position (15 degrees east). So, 0 degrees + 15 =
degrees =3D 15 degrees. You want to point your telescope on a compass =
bearing of 16 degrees to achieve true north. Rotate the ring on your =
compass clockwise until the offset pointer is roughly above 16 degrees. =
Now, with your compass needle pointing exactly at magnetic north, the =
line running at 15 degrees is the direction you want to point your =
telescope in.=20
If all else fails at least you know which direction to nudge your =
telescope in to achieve true north. In your case it needs to go east or =
"clockwise" by 15 degrees or so.
Remember, this will only give you a rough start. You will still need to =
do some drift alignment if you're aiming for long duration accuracy (for =
astrophotography etc.).
Good luck.
----- Original Message -----=20
Sent: Wednesday, July 04, 2001 2:00 AM
Subject: [M]: RE: Magenetic Declination web site.
Can anyone explain how to north align my scope using this info. I have =
all the numbers but dont really know how to
put them into practise.
I have a compass with a rotating ring marked in degrees. I think I =
have to twist this ring until it is offset by the magnetic
declination and then point the compass arrow to the now offset north, =
the problem is I dont know whether to turn the ring
eastward or westward.
my declination (according to the site below) is 15d east (the meade =
manual says 16d east)
I know this is probably second nature to many of you but I have had to =
mess with maps or compasses before
and couldn't find much on google to help either.
thanks
-----Original Message-----
Sent: Monday, July 02, 2001 5:23 PM
Subject: [M]: Magenetic Declination web site.
For those interested (and particularly those who do not live in =
North America and for whom the magnetic declination chart in the LX200 =
manual is useless) here is a web site which provides magnetic =
declination values from any latitude and longitude. There is also some =
interesting information on the subsequent calculation of true bearings =
and other variables.
http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl
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<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
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<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Dave,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>On the web site's output page, =
c</FONT><FONT=20
face=3DArial size=3D2>lick on the "D" above the value you get for the =
magnetic=20
declination. It will take you to a description of what it means, and how =
to use=20
it. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>In essence, the true bearing (the =
direction you=20
want to point your telescope in, ie, true north in this case) is the =
magnetic=20
bearing (the direction the compass is pointing) plus the magnetic =
declination=20
which was computed for your position (15 degrees east). So, 0 degrees + =
15=20
degrees =3D 15 degrees. You want to point your telescope on a compass =
bearing of=20
16 degrees to achieve true north. Rotate the ring on your compass =
clockwise=20
until the offset pointer is roughly above 16 degrees. Now, with your =
compass=20
needle pointing exactly at magnetic north, the line running at 15 =
degrees is the=20
direction you want to point your telescope in. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>If all else fails at least you know =
which direction=20
to nudge your telescope in to achieve true north. In your case it needs =
to go=20
east or "clockwise" by 15 degrees or so.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Remember, this will only give you a =
rough start.=20
You will still need to do some drift alignment if you're aiming for long =
duration accuracy (for astrophotography etc.).</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>G</FONT><FONT face=3DArial size=3D2>ood =
luck.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, July 04, 2001 =
2:00=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> [M]: RE: Magenetic =
Declination=20
web site.</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D554465517-03072001>Can=20
anyone explain how to north align my scope using this info. I have all =
the=20
numbers but dont really know how to</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D554465517-03072001>put=20
them into practise.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001></SPAN></FONT> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D554465517-03072001>I=20
have a compass with a rotating ring marked in degrees. I think I have =
to twist=20
this ring until it is offset by the magnetic</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001>declination and then point the compass =
arrow to the=20
now offset north, the problem is I dont know whether to turn the=20
ring</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001>eastward or westward.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001></SPAN></FONT> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D554465517-03072001>my=20
declination (according to the site below) is 15d east (the meade =
manual says=20
16d east)</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001></SPAN></FONT> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D554465517-03072001>I=20
know this is probably second nature to many of you but I have had =
to mess=20
with maps or compasses before</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D554465517-03072001>and=20
couldn't find much on google to help either.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001></SPAN></FONT> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001>thanks</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D554465517-03072001></SPAN></FONT> </DIV>
<BLOCKQUOTE=20
style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px =
solid; MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> Paul Luckas=20
2001 5:23=20
Declination web site.<BR><BR></DIV></FONT>
<DIV><FONT face=3DArial size=3D2>For those interested (and =
particularly those=20
who do not live in North America and for whom the magnetic =
declination chart=20
in the LX200 manual is useless) here is a web site which provides =
magnetic=20
declination values from any latitude and longitude. There is also =
some=20
interesting information on the subsequent calculation of true =
bearings and=20
other variables.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2><A=20
=
href=3D"http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl">http://www=
.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl</A></FONT></DIV></BLOCKQUOTE>=
</BLOCKQUOTE></BODY></HTML>
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