Reply To: Air Navigation

[JDavHouston]

“As you probably know, the nautical almanacs stop publishing the lunar tables back in the 1910’s”

I didn’t know that, as I’d only looked at the air almanacs. I’m planning in the near future to get checked out in a Seneca and start flying with friends from the Houston area over to Miama/Tampa/Key West (all celestial, is the idea, with them flying and me in the back seat navigating to see how I do!)

“In this book, the author states that the natural horizon, whenever it is visible, is much preferred to the bubble horizon; and apparently, even the maritime sextant using the two pots of reflective liquid placed on the ground–are preferred to the bubble-octant / sextant’s horizon which is the least preferred method for land navigation.”

Having messed with it, I can explain that one now.

As one looks down into the instrument, one has to ‘judge’ when the center of the bubble and the star are properly aligned, and even small motions of the hand send it all over the place. In a plane, this is the best one can hope to get, but it is easily the worst way to try to do it! Any other method of a horizon will easily be superior.