In my mind, it was something akin to a big game hunting safari of the 1920’s – not on the plains of Africa, but on the crests and troughs of the Atlantic Ocean. Instead of a gun, I was using a sextant, stalking the long sought-after elusive three-star fix. It had been years since I had the thrill of observing three stars, plotting them into an almost perfect pinwheel. I knew the odds for repeating that experience were long, but as with many other celestial navigators, I live on hope.
When I arrived as crew aboard the 110-foot motor yacht Relentless for a trans-Atlantic passage, I was confident knowing that there were two good sextants aboard, an Astra 111B and a Freiberger.
The Astra, a good Chinese-made sextant, is lightweight and easy to use, but this one had mirrors that needed serious adjusting. Unfortunately, the necessary Allen wrench was nowhere to be found. I couldn’t remove the large index mirror so instead I used the Freiberger, a model built of an aluminum alloy, calibrated to degrees and minutes.
I was surprised at the Freiberger’s relatively poor optics, given the association with the Zeiss Company, renown for quality lenses. The Freiberger felt heavier than the Astra and lacked, at least to my mind, a certain elegance. Still, it was a reliable tool with a minimal index error. Fortunately, there were also adjusting wrenches in the Freiberger case that fit perfectly into the Allen screws on the Astra. So, after adjusting the mirrors on the Astra, I used that for my celestial observations for the rest of the passage.
I had no problem taking multiple sun sights and moon observations and could even get a pretty accurate moon sun fix (according to the GPS) but as far as the much-desired star observations I was a complete failure. I’m not sure if this was due to the pitching and rolling motion of the ship or the fact that I am past three score and ten and possibly just too old to seek my 3-star quarry. My eyes are good, my balance less so.
I was a discouraged but not defeated. If the opportunity comes again, I will make another attempt.
I was able though to regularly observe LAN for finding latitude. This is a Lower Limb observation. On our way from Bermuda to the Azores, approaching from the north, the sky has become overcast, but I still get a sun sight. This is the downside of the noon sight; even though it produces latitude, if it’s overcast at noon, you’re out of luck. Nineteenth century mariners would DR until the next day when they could get a noon sight as most of the captains were only capable of finding latitude at noon.
On May 19, the DR position N 38° 27’ by W 31° 15’.
The Height of Eye is 15 feet with an index error of 2 minutes on the arc.
The time of LAN in GMT is 14:02.
The HS at the time of observation is 71° 19.8’.
1. Find HO.
2. Find latitude at the time of sight.
3. Plot latitude line.
For the answers go HERE.