Wanted to learn a bit more about the difference between magnetic north and celestial pole. Scott and I had discussed it at a couple of recent (Toronto area) star parties, that it was about 10° off. But I couldn't remember if it was east or west.
Looked at wikipedia briefly. The article referred me to the US and UK geological surveys but I didn't really see what I was looking for. Went to the telescopes Yahoo!Group and searched the message archive. Sure enough, found a note. The author described using a compass and then compensating. He referred to Canadian and US geomagnetic web sites.
In the Natural Resources Canada web site, I found the Magnetic Declination Calculator. Very handy. I've added a note to my observing checklists to review this. While it doesn't need to be checked often for a particular location, it should be used if observing from different sites, distant from one another.
This will prove useful for day time observing...
Sunday, October 14, 2007
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