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iPhone10 Fix

When I think of a fix, a Starbucks Tall Pike usually comes to mind. I can’t survive without my coffee. This morning I left early to go downtown. The minute I walked out of our building, I felt the -20degC temperature and then I noticed a gleaming half moon in the clear blue sky. I could not resist taking an altitude with my iPhone. It was tough holding the phone in my bare hands. I am sure the reading is out by a degree or so. Later on when I returned home, I got two shots of the sun. These are my results. I reduced my sights using NavAlgos and checked with iMariner. The fix was determined with NavAlgos, Admiralty NavPac and iMariner.

The first sight on the Moon was out by approximately 1 degree, which is the iPhone level increment. In the last blog post I was right on the money, this time not so lucky. The third sight on the Sun was fairly close at 13.4′. I aimed the top edge of the iPhone to the upper limb of the Sun, and used a Silva Compass mirror to see the iPhone screen and block the Sun’s image. Again a lucky break.

Figure 1 Half Moon Jan17_2020_11:32GMT Hs = 39deg

Hs1 = 39deg Time = 07:32EST = 11:32GMT Moon
Lat = 43deg 42.6’N Long = 79deg 24.1’W (Known Position)
Lat = 43deg 43′ Long = 79deg 24′ (Estimated Position)
Intercept = -62.3′ (NavAlgos EP) = -61.9′ (iMariner EP)
Azimuth = 185.3deg

Hs2 = 24deg Time = 12:23EST = 16:23GMT Sun
Lat = 43deg 42.6’N Long = 79deg 24.1’W (Known Position)
Lat = 43deg 43′ Long = 79deg 24′ (Estimated Position)
Intercept = -9.5′ (NavAlgos EP) = -9.7′ (iMariner EP)
Azimuth = 163.5deg

Hs3 = 18deg Time = 15:53EST = 19:53GMT Sun
Lat = 43deg 42.6’N Long = 79deg 24.1’W (Known Position)
Lat = 43deg 43′ Long = 79deg 24′ (Estimated Position)
Intercept = 13.4′ (NavAlgos EP) = 14.1′ (iMariner EP)
Azimuth = 215.5deg

Taking the 1st and 3rd altitude, the Fix:

Lat = 44deg 52.8’N Long = 82deg 21.2’W (NavAlgos)
Lat = 44deg 52.8’N Long = 82deg 21.2’W (NavPac)
Lat = 44deg 57.6’N Long = 81deg 35.94’W (iMariner)

Figure 2 Moon Sight Reduction 11:32GMT NavAlgos
Figure 3 Moon Sight Reduction 11:32GMT iMariner
Figure 4 Sun Sight Reduction 16:23GMT NavAlgos
Figure 5 Sun Sight Reduction 16:23GMT iMariner
Figure 6 Sun Sight Reduction 19:53GMT NavAlgos
Figure 7 Sun Sight Reduction 19:53GMT iMariner
Figure 8 Moon 11:23GMT & Sun 19:53GMT Fix NavAlgos
Figure 9 Moon 11:32GMT & Sun 19:53GMT Fix NavPac
Figure 10 Moon 11:23GMT & Sun 19:53GMT Fix iMariner
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By Jeremy Clark

Jeremy Clark is a Senior Telecommunications Engineer and Advanced Amateur Radio Operator VE3PKC. He is the author of E-Books on Telecommunications, Navigation & Electronics.