> Hi, yes I agree - can you tell me how I find out the datum which > Mapblast uses here in Europe?? > On the other hand - as I stated before: to what accuracy do we > aficionados need the precision differences ?? I've been silently watching this discussion, and my opinion is this: If the difference in the various geoids is < 50m, and if the error range in TLE's is already 500m, then I think the errors in the various geoids can basically be ignored. Besides, it has been my general experience that even if I make predictions for a city about 10km away from my real position, I get the same predictions than for the dwelling in which I live and observe - even for Iridium flares. At some point, I think positional accuracy becomes overkill. My tolerances are: General prediction radius: 30 to 50 km Iridium flare prediction radius: 5 to 15 km Clock tolerance level: 10 to 30 seconds Those levels are for if I just want to _see_ an object under ordinary circumstances. In unusual cases I may want more stringent tolerances, but the above is good enough for me. So, to put this whole e-mail down to one line: "Close enough is good enough. Now just leave it alone, or be more accurate to no visible advantage." ------------------------------ Jonathan T. Wojack tlj18@juno.com 39.706d N 75.683d W http://www.angelfire.com/stars2/projectorion 4 hours behind UT (-4) ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Sun Aug 19 2001 - 18:31:50 PDT