A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2017 Oct 3, 12:25 -0700
Just a quick note on this topic. That's a detailed analysis in your first post --including over twenty-five attached images! I'm reminded of a certain "twenty-seven eight-by-ten color glossy photographs with circles and arrows and a paragraph on the back of each one". I have not had time to look at that post in detail, and I don't know if I will have time soon. A couple of thoughts:
- You refer to my lunars web tools as NavList's web calculator repeatedly. Why!? Well, never mind "why". Do not do that :). My work and product are not the property of the NavList community, and it struck me as bizarre that you referred to them that way.
- Next, I hope you finally understand now, after this latest exchange, that your focus on details about delta-T values was completely wrong-headed. It is irrelevant. You're taking a relatively straight-forward, minor issue in ephemeris calculations (absolutely not part of practical lunars or practical occultations unless one is dealing with old software) and making a mountain out of a molehill.
- Regarding Fred Espenak... He is not "NASA". He's "Mister Eclipse"! :) He's an avid amateur astronomer who runs eclipse tours and does anything and everything connected with eclipses, and he is an expert in eclipse calculations in the same sense that some NavList members are experts in various specialized topics. He was formerly employed by NASA, which is a vast bureaucracy, and his managers (before he retired) gave him an open ticket to do public outreach regarding eclipses at all levels. While his posted tables of delta-T polynomials are nice to know about, you should not treat them as "NASA research" or as the "final word". In short, don't obsess over them. There are plenty of near-equivalents, and for lunars, very coarse values, anything within a few seconds of time, are good enough, no matter where you get the numbers (if you insist on "rolling your own" calculations, which is clearly a unique hobby).
- And hey, you can be friends with Fred Espenak... Facebook friends! He's on my contacts list and he has thousands and thousands of FB friends accumulated before and through this summer's solar eclipse in the US. He has retired to a little astronomy retirement community in the desert Southwest where the skies are dark, and all the neighbors have backyard observatories. :)
- Finally, my online tools are for working lunars. Occultations are not lunars. These tools may have some use in occultations. We have discussed this all before. Nonetheless, I will try to take a look at your latest analysis when I have time to see if there is anything new.