sun compass

[markyb]

i have a sun compass that i use with a normal compass tor show were the sun will be at a given point in the day it came free with a photography magazine here in the uk
will this compass be any use in the canary islands ie: tenerife. i go next week and was wondering if i could use it there

[Jon]

Is this a mechanical or an electronic device? Does it have provisions for setting local time zone and lat/long? If it lets you set local time and location or lat/long it should be usable anywhere. I have a sun compass for my cell phone (Nokia N95) which does this. (http://qcontinuum.org/compass/index.htm needs J2ME)

[markyb]

this is it. it is used with a normal compass

[SkipD]

Look at the statement in the upper left corner - "Calibrated for 51°N 0°W". That means it's only good for close to the spot on the earth that it's set up for (my map says about 50 miles south of London).

[Jon]

Ah! I expect you'd find that it shows everything farther north in the summer and south in the winter than you'll experience; the further away you get from the latitude they used to calculate it, the further off it'll be. There's about a 12 deg. difference between London and Rome at the Summer Solstice. And you'll need to adjust for local magnetic declination.

[markyb]

i dont fully understand this kind of stuff
i know it give an indication of were the sun will be
is there a similar chart for the canary islands

[Jon]

Nov. 8 expect sunrise at about 108 deg; by Nov. 15, it'll be around 111 deg. True. Sunset will vary from 251-249 deg.
Values from Ephemeris (http://home.comcast.net/~jsachs34/) by Jonathan Sachs, a Pocket PC app.

[Lowner]

MarkyB,

Apart from the Latitude difference, there will also be a change in the Magnetic Variation. This will change the compass bearing of the sun as well. Your little gadget was created for a very local area.

[Tdragone]

I did this a looong time ago for southern california's latitude after reading about this on another thread here. It requires some excel work and some copying and pasting; but I figured out how to do it for anywhere in the world. If I have some time in the next few days; I'll try reinventing the wheel and posting instructions.

[ben_r_]

Thats kinda, cool, I have never seen anything like this before.