NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Art Leung
Date: 2023 Apr 3, 11:06 -0700
I'd like to say that my first attempt at clearing the lunar distance went perfectly and I was within seconds of being correct. But, like most things worth learning, there is a bit of a learning curve.
I was out the night before and realized that the Moon would be very close to Regulus the next night. Seemed like a good way to learn the mechanics.
I chose my SNO-T to take out because it is the lightest of my nautical sextants and I would have to hold it off at an odd angle (about 45deg) to bring the two together.
What I had not counted on was the shades of the SNO-T - they are rather binary. Since the Moon was lower and more north of Regulus, I set up to view the Moon via the horizon mirror and Regulus using the index mirror. But the horizon shades were a choice of "Moon too bright" or "What Moon?". I could not bring the star to the near limb because its brightness washed out the star - I resorted to adjusting the star away from the limb and then adjusting/swinging the star to where I hoped it would graze the limb. First lesson learned: take the C+P with the polarizing shades next time.
I did try and plot the measured distances over 12 minutes of time and there was an increasing-distance trend evident in the plot, but the data was so bad that there wasn't a standout line that I could see.
I also realized my breath was fogging the telescope objective lens - and my Cat Crap was in the box with the C+P. Lesson 2 - get the Cat Crap into the right box. (In case anyone is concerned for my sanity, Cat Crap is a paste used to prevent fogging on lenses.)
I did try to use the 8x inverting telescope that my SNO-T has. Being longer, it did seem to solve the breath-fogging issue, but I was nowhere near steady enough to make it work even if the "Moon too bright" shade issue could be solved. I wonder if sitting in a comfy folding chair with an armrest would make holding things a bit easier.
The mental gymnastics weren't too bad - I used the Stark Tables - and were relatively straightforward.
The local weather guessers say it will be cloudy for the next 10 days and the Moon will be below the horizon in the evenings long before I can try again. But maybe it will be clear enough after to shoot the Moon and Sun.
At any rate, i have a new celestial navigation skill to learn. Thanks to you all for giving me the inspiration.