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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Eclipses of Jupiter's moons: Did ships tend to carry the requisite equipment?
From: George Huxtable
Date: 2004 Feb 17, 21:35 +0000
From: George Huxtable
Date: 2004 Feb 17, 21:35 +0000
Patrick Stanistreet wrote- >I plan on testing the method of Jupiters moons, at 4 am >this morning about 60 miles north of Los Angeles, CA >I could see three moons for about 30 minutes then clouds >rolled in ending the observations. My telescope is >rather small so I wont be going for much accuracy. >Since I dont have any tables I tried a search on >google using jupiter moons ephemeris > >First link was helpful > > http://ephemeris.sjaa.net/0206/d.html > >He had a link to some tables and source code which I have >not tested at this time but will be using the tables to >time events. > > http://www.projectpluto.com/jevent.htm > >I am curious what type of data appears in George Huxtable's >almanac of 1864 as compared to the tables at projectpluto. ==================== The 1864 almanac gives times of events for the first 3 satellites. The events that are tabulated are- Eclipse (disappearance or reappearance), occultation (ingress or egress), transit (ingress or egress), transit of shadow (ingress or egress). Greenwich Mean times are given to the nearest minute except for the eclipses, which are timed to a tenth of a second. Of course, only a fraction of those tabulated events are visible from a particular location. As for modern predictions, as I remember the Astronomical Ephemeris provides predictions of Jupiter satellite events, but only to the nearest minute. Paris is the natural home of accurate timing, and there's an annual publication, produced in Paris (in French and English), giving very precise predicted times for all these events. The website that Steven Wepster has identified may provide that same data, as I recognise in its address the initials bdl.fr (presumably "bureau des longitudes.france"). I wish for clear skies for Patrick, George. ================================================================ contact George Huxtable by email at george@huxtable.u-net.com, by phone at 01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. ================================================================
