Quote:
Originally Posted by Wavytone
Ok ... how many ways to find Nirvana...
1. A compass, as you know. Crude, not very accurate.
2. If you can see a nice distant landmark such as a church, tall building or even a mountain peak, buy a topographic map at scale 100,000:1 and locate your position, the landmark at measure the bearing to try north directly with a protractor. You can figure the rest, as an engineer.
Topo maps are also available as PDF and you might be able to bludgeon google maps into giving you the bearing directly.
3. Find your longitude, and determine the actual time the sun cross the meridian on (say) tomorrow. If you have a plumb-bob handy the shadow points exactly north south as the sun crosses your local meridian, ie at local solar noon. Done with care this is likely to be accurate to 0.5 degree or even 0.25 degree and a lot better than a compass.
Hint: got a tripod ? Hang plumb bob from tripod.
4. Other methods involving the sun either side of solar noon, a circle drawn on level ground using string and a nail, and a plumb bob suspended over the centre of the circle casting shadow. Wait for plumb bob to cross the perimeter of circle near sunrise and sunset, mark these angles and bisect the interior angle, this give north or south. Simple geometry known to the builders of Stonehenge and the pyramids. Won't bore you here, too long to explain, maybe you will figure the rest.
5. Use the stars and the dec circle on your mount. Choose a star low near the east or west horizon and set the dec axis of the mount to the stars declination. Loc the dec axis firmly. Now adjust the azimuth of the mount to centre this in the scope.
Assumes mount and dec circle are accurately square and calibrated. Not a safe assumption unless you can test it. Google "calibrate theodolite" to see what this entails.
6. Using an astro map of the stars near the S pole, choose one that culminates (ie crosses your local meridian) in the evening. Using the RA of this star calculate the exact time it crosses your meridian. A bright and dead easy star is best for this. Set the mount so the dec axis is horizontal (use a level) and adjust the azimuth of the mount to centre this star at the time it culminates. Repeat for a few other nearby stars to make sure you have done it right.
This should align the mount azimuth within the resolution of the dec circle or better.
7. Drift aligning using your scope. Google this or find the page on IIS.
|
Thanks for your reply - plenty to absorb and work with here.
7. Will be the most likely ultimate solution. At home I am hemmed in and only have a restricted patch of sky to play in.