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Re: Sight practice this weekend and next week in SoCal?
From: Daniel Hazen
Date: 2025 Apr 13, 08:57 -0700

Attached please find images of 6 artificial horizon sun sights taken on April 11 2025. I'm pretty pleased so far. The closest intersection is 1.4 nm and the furthest is 8.45 nm.

Initially one of my sights was way off because I had an hour time zone error in converting to UTC. Probably better to just use UTC from the start and not mess with time zones!

Another of my sights was way off because I apparently read the degrees incorrectly. I had taken 3 or 4 sights in a row and that particular sight was so different from the others I should have noticed the discrepancy.

I made another error in calculating one circle of positon when I just used Ho instead of 90-Ho for determining the radius.

I paid more attention to adjusting the sextant and I actually didn't account for any index error in my calculations.

It's very windy at Gaviota which may have impacted my ability to hold still and it also sometimes created disruptions in the AH images despite the wind shields.

I'm in my car and it's too inconvenient to do proper Marc St. Hillaire sight reductions so I've temporarily reverted to using my Topo 9.0 software and just used circles of position rather than lines of position. It's reliant on my laptop but it seems accurate for the intended purpose. (There are free websites which allow for creation of circles around fixed points if that is of interest or use to anyone.)

I've done a lot of regular sun sights which I will reduce later. One potential problem is the ocean horizon is quite fuzzy to my eye, and that may create an issue. I've also done sights on the Moon, Venus and Sirius which I will also reduce later.

hanks for the bandwidth!

Daniel

File:
April-11-2025-6-Gaviota-AH-Sun-Sights.pdf

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