Hadley Cell Anecdote
From: Michael Bradley
Date: 2020 Aug 19, 05:39 -0700
' "Simplify and repeat"
... hence 0.1 arc minutes per 10 deg of Altitude up to 60 deg'
in response to the wrong thread.
Sorry about that, my mistake.
We've had a peculiar 'Hadley Cell' experience on the English NE coast in the last couple of weeks. There's been a moist, warm, high pressure feature parked just north of Scotland. Very unusual. It has fed what certainly feels like tropical maritime North Easterlies (Portugese Trades?) onto our coast, and the weather has been misty, warm, and wiith multiple layers of cloud above us. No good for astro at all. I remember very well similar conditions when approaching the Azores from Spain, having to keep the sextant on the bridge deck with the box lid open throughout the day in the hope of being ready to shoot the sun at a moment's notice when it momentarily appeared through the cloud levels.
So when I saw signs of of thinning cloud to the North East out of the study window two mornings ago, I chose to drop everything and head for the beach. Too much haste!
The sight wasn't much use by normal standards, but plenty good enough to find an island by, and something to be pleased about in the poor conditions. Astron gave it 4.5' T 130, and my favourite 'five pieces of paper' method Table 4 and Hav/Doniol plus Ix graphic 4' T 129. So re-inforcing the idea that you can confidently expect to find an Azores island in poor conditions without electronics but with a sextant and five pieces of paper .....