[amsat-bb] Re: Dont loose the north
lihan161051 at sbcglobal.net
Fri Dec 28 09:29:58 PST 2007
I was just going to say that Polaris is close to the north celestial
pole but not quite exactly on it, and if you're absolutely insanely
obsessed with accuracy, you probably want to take two shots on it 180
degrees apart (12 hours apart in winter, if your latitude is high
enough that you can fit two observations 12 hours apart into one
night, or the same time on two nights 6 months apart, or whatever),
and split the difference. If you're aiming at satellites, an error of
less than a degree isn't going to matter much, though .. your
antenna's main lobe is almost certainly wider than that. :)
On Dec 28, 2007, at 10:49 AM, Michael R. Owen wrote:
> All -
> For what it's worth, Polaris' declination is 89.2 degrees.
> Consequently, it can be as much as 0.8 degrees "off" from true North.
> For aligning an antenna whose beamwidth is 15-30 degrees, this error
> trivial of course.
> Luc Leblanc wrote:
>> I don't know if the old Columbus trick works in the southern
>> hemisphere but
>> here i calibrate my antennas on Ursa Major AKA The north star.
>> Just place yourself just under your tower or your beam supporting
>> locate the north star and pointed your antenna.
>> For those who are not able to see the north star too bad take a GPS
>> i check
>> with mine against the north star and its closed enough just make
>> sure you are
>> programming to see the thru north not the magnetic north.
>> "Is it true that water flush in reverse side in drain if you are in
>> southern hemisphere? an old non believer saying!
>> Luc Leblanc VE2DWE
>> Skype VE2DWE
>> WAC BASIC CW PHONE SATELLITE
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