Reply To: Practice sights for a beginner.

[David Williams]

I live not far from a Pacific Ocean beach, so I often go there to practice my celestial navigation using the Astra III pro sextant. But on occasion at home from my driveway, I use a Celestiare artificial horizon. Everyone must concede that it takes practice, lots of it, to achieve honorable results. At the beach, I record less than 2 nautical miles error. At home I usually record less than 5 nautical miles error, unless I have wine. The artificial horizon is not as rewarding as the true horizon.
I use the Celestaire # 0511 practice bubble horizon. To it I attached the slip-on rubber eyecup #0505 over a small piece of snuggly fit PVC pipe. I wear a long-billed hat to keep the above sources of light out. There are internal bubble reflections. Over the hole that illuminates the bubble, I attached a red LED, with a 48 ohm resister and a 5K pot to adjust LED brightness, all mounted on a well-shaped block of wood to prevent slippage of position. The block can be moved back and forth to enable adjusting of the bubble reflected brightness. To provide power to the LED, I tapped into the handle’s battery wire with a small connector. With this assembly, I can do late evening sextant practice. It may not be ideal, but it works! With a good wine, I reliably achieve my 5 nautical mile error. Careful calibration of the instrument error with the bubble horizon against the true ocean horizon ( with dip) is necessary.
I programmed my HP-35 calculator with the sight reduction formulas to make the practice of sight reduction more efficient. I use only the current Nautical Almanac because there are slight changes year to year, especially with the planets.
I formally urge all interested to practice celestial navigation just to preserve history. Teach others to do it. Use the GPS only to measure accuracy of the fix. I find doing the plot on a NOAA navigation chart quite revealing.