NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2026 Jun 20, 14:31 -0700
Hello Josh.
You asked:
" it's not exactly 54.00 is it?"
No, but close. I see Geoff Hitchcox has added a detailed follow-up. :)
What's the exact time of the solstice? I'm not sure. But some things to keep in mind... Most (casual) sources talk about the declination of the Sun. When it reaches its maximum in June of every year, that's the farthest north that the Sun will reach in the year. It's all downhill from there! The timing of maximum declination is difficult to define and measure. Instead we need the time when the Sun reaches a particular longitude on the celestial sphere. I'm not sure about the exact modern definition. We can look at the (geocentric) RA/SHA of the Sun or the λ (lambda), ecliptic longitude, of the geocentric Sun. For the RA/SHA case, it looks like the geocentric Sun hits SHA=270.0000° (or RA=90.0000°) at 08:24:32 UT on 21 June 2026 (a little more than 12 hours from now as I type this). I'll use that time.
Next we need the Sun's GHA. For 08:24:32, I find a GHA of 305.6894°. That's identical to the West longitude of the subSun point. To get an East longitude to play nice with modern mapping apps, we subtract that from 360 which gives 54.3106° E. The corresponding latitude (dec of the Sun) is stable for a relatively long time and equal to 23.4380° N.
Go find that spot in Google Maps and then zoom out a bit. See my attached image. This is not too far from a unique feature in southern Abu Dhabi, United Arab Emirates. In the southern desert, right on the edge of the giant dunes of the Empty Quarter, there's a huge crescent of villages and vegetation visible, sixty miles long, visible from orbit. That's the Liwa Oasis. Tomorrow morning, at the moment of the solstice, the Sun will be at the zenith only a few dozen miles away.
Frank Reed
