NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: USNO Celnav data is back
From: Paul Hirose
Date: 2022 May 4, 16:52 -0700
From: Paul Hirose
Date: 2022 May 4, 16:52 -0700
On 5/4/2022 7:00 AM, Dave Walden wrote: > For Assumed Position: Latitude N 39º 0.0', Longitude W 77º 0.0' > For 2022 May 4 at 2:44:00 UT All degree symbols in your post look like this: º, i.e., a tiny letter o with underscore. I do not see that on the web page, but when I copy and paste from the page to a document, the same thing happens. Some years ago I wrote about this phenomenon in some other context, but I can't remember the details. It's not clear to me why the application can't make life easy for the navigator by computing the expected topocentric angles. There could even be an input for height of eye. Instead, it takes the traditional approach where the navigator must correct the observed altitude to obtain the equivalent geocentric angle Hc. And I think it ought to compute Moon altitude for the appropriate limb, or just compute altitude of both limbs. The AM/PM UT1 input format is peculiar and annoying since the precise meaning of 12 AM is ambiguous. Is it 0000 or 2400? If you enter 00 hours the USNO application automatically changes to 12 AM. But that convention is not universal: https://www.whec.com/rochester-new-york-news/midnight-birth-leads-to-year-long-battle-over-birthdate/6452977/?cat=13421 -- Paul Hirose sofajpl.com
