A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Jim Rives
Date: 2020 Jan 30, 18:59 -0800
Well, it certainly helps to actually use the right data. Sloppy worksheetmanship on my part. My apologies. Changing the AP to 42d 58.8N and 70d 57.4W didn't change the error, as you predicted. But with that changed AND using the right LD cleared of 38.3 my error dropped to 1.1'. So, if I was to explain to an imaginary someone what this means I might say that I predicted that at GMT 2210 the LDcleard would be 16d 11.3', but I measured and cleared to 16d 12.2', meaning that the GMT was actually later than 2210. How much? 1.1' times 4 seconds, or 22:10:04? Is that correct? And I still couldn't explain where the "approximate error in Longitude of 0d 28.8" comes from or what exactly that means. My longitude could be off 28.8d?
Thank you for taking the time to comment on this, Frank. I think way way back, about 7 weeks ago, when we first tried the moon-venus sight in Mystic when I could barely get the sextant in a weird enough angle to capture both images. Soon I may even be able to talk intelligently about what I'm doing. It is great fun trying though. Tomorrow I'll try the sun and venus. Perhaps get lucky and even pick out venus at mid-day.