NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar distance presetting exercise
From: Peter Hakel
Date: 2019 May 26, 20:40 +0000
From: Peter Hakel
Date: 2019 May 26, 20:40 +0000
Frank,
Yes, you guessed it - this is for fun and also to exercise the spreadsheets here in New Mexico far away from the ocean, without having to set up an artificial horizon. Also, I began learning CelNav 10 years ago with a plastic sextant and I experienced all the issues with variable index error that have been discussed on this forum. I only acquired a metal sextant last year and I can confirm what others have said, that while a plastic sextant is good enough for practical purposes, using a metal one is another experience altogether. I am yet to travel to a sea coast with it, but that’s definitely on my list of things to do.
Adding refraction to the ld_prec.xls spreadsheet would have been an extra step that I didn’t feel like doing; it would have been enough for me to see both the Moon and the body in the same field of view of a higher-power scope - the fact that they line up so well adds to the satisfaction from this exercise. That said, nautical refraction formulae and tables are built for sea level, whereas I am at an elevation of 7320 feet (2230 m); I don’t recall right now how much difference that makes for altitudes (perhaps aircraft pilots on NavList can comment), and I believe that it is academic for lunar distances.
Peter Hakel
35° 53’ N, 106° 19’ W
Yes, you guessed it - this is for fun and also to exercise the spreadsheets here in New Mexico far away from the ocean, without having to set up an artificial horizon. Also, I began learning CelNav 10 years ago with a plastic sextant and I experienced all the issues with variable index error that have been discussed on this forum. I only acquired a metal sextant last year and I can confirm what others have said, that while a plastic sextant is good enough for practical purposes, using a metal one is another experience altogether. I am yet to travel to a sea coast with it, but that’s definitely on my list of things to do.
Adding refraction to the ld_prec.xls spreadsheet would have been an extra step that I didn’t feel like doing; it would have been enough for me to see both the Moon and the body in the same field of view of a higher-power scope - the fact that they line up so well adds to the satisfaction from this exercise. That said, nautical refraction formulae and tables are built for sea level, whereas I am at an elevation of 7320 feet (2230 m); I don’t recall right now how much difference that makes for altitudes (perhaps aircraft pilots on NavList can comment), and I believe that it is academic for lunar distances.
Peter Hakel
35° 53’ N, 106° 19’ W
