Hello, me again and yes I am still confused about this declination thing....
according to the declination website, My Magnetic declination is
+8 degrees 4'
and Declination is Positive East
Which one is right
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or
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Please, I have it pretty well set up on the pavers in my back yard but I am about to travel and would like to know how to know at each destination which way to point
Thank you
sorry it seems the photos did not show
The first one I have the phone so that it is pointing at
180 degrees Mag and 188 degrees true
the second is at
172 degrees Mag and 180 degrees true
My declination is 8 degrees 4' positive east
Thank you
If your trying to find the celestial South Pole with your telescope set up using the Solar Noon shadow method works well
I’ve set up my rigs endless times over 5 years in different locations using the good old Suns shadow to find “True South” and using a digital inclinometer for Altitude setting on the mount and it works great , sometimes within 15 to 20 arc minutes, so it’s a good starting point to fine tune your polar alignment.
See attached
When I first started the hobby I tried using an expensive Silva compass with magnetic declination together with aluminium straight edges etc.... waist of time , I had different readings in different locations as the earth’s magnetic field is a moving target in different locations depending on the amount of iron in the regolith. Sold to compass to a bushwalking club
Using the Suns shadow doesn’t lie , it’s correct every time and in any location
See attached
Hope this helps
Good luck !!
I've done similar solar alignment but rather than use a dowell, I hung some 4mm - ish cord from a ladder with a heavy weight / plumb bob on the end which seems to work well providing it's not windy. Then just make sure your stellarium/sky safari/luminos etc app has your correct time and coordinates, select the Sun, and when it's azimuth reads 0.00, your shadow points true south - mark that with whatever is appropriate for your location - string / line in sand / paint etc.
This is not a bad system to obtain true north/south. He says to use Google Earth, but you actually have to download Google Earth Pro (free). Just scroll and click on the "Polar alignment using assistance from Google Earth" tab. As you will see, he uses a digital inclinometer app on his iphone to set the altitude.
I can't really use it at my place because I have no real line of sight to the north or south because of tree but it will work in many situations.
I would think anyone that also requires the term declination for stars (sky and sea navigation) would not use magnetic declination also but rather magnetic variation.
As I mentioned in my previous post , solar noon shadow method to find “True South” never fails anywhere in the Southern Hemisphere
Cost nothing, takes a few minutes to set up and is very accurate as long as your accurate with your set up ,timing and marking
I’ve used expensive Silva compasses with magnetic deviation all of which have been inaccurate , they are a moving target dependant on the composition of the regolith ( iron ) in the area ( I observe and image from 2 different locations 220km apart )
As a surveyor in a former life could we please use the correct terminology - it is "magnetic deviation" (from north) not "declination".
As a former navigator the term we used was MAGNETIC VARIATION (and the associated mantra for applying the correction west is best east is least) but declination is also used, I never heard it called deviation there is also the DIP but that is another story....
In the Aussie Navy we called it Magnetic deviation... Older people who had been around longer called it magnetic correction. Language changes over time.
