On 02/07/2016 04:04 PM, Jonathan McDowell wrote: > I was thinking more the difference between WGS-84 and the spherical 6378 km > Earth that's > used in SpaceTrack.org which can easily be 20 km at least. But the apses are > near the equator > in this case, for the latest elset I get > 465.1 x 501.9 km mean els, geocentric spherical Earth > 468.3 x 505.2 km WGS84 heights at geocentric peri/apocenter > 466 x 514 km WGS84 actual max and min heights above ellipsoid (which are > not at the apses of the ellipse) > 458 x 503 km osculating els at 1310 UTC > But all of these are different from the DPRK's claimed 495 x 500. So I agree > this is either a prelaunch estimate, > or an overoptimistic calculation by the DPRK orbit tracking folks under pressure > to make the boss happy :-) i can agree with that... i admit that i didn't try to do the maths to see the actual differences... there's a lot of software out there that still uses the WGS72 values (eg: celestrak's published code)... i've asked some of them, in the past, if/when they were going to update to the WGS84 value and got no response OR something like "it isn't that critical so the report is marked as 'won't fix'" :? if i had more knowledge of what numbers came from where, i would at least try to update the libraries i use in my software but :shrug: i can see some similarities but quickly get lost in the details when trying to hunt down others :( /me doesn't have as much of an eidetic memory as once upon a time when caffeine was the main source of energy... /me left the big city "rush rush rush, go go go, caffeine caffeine caffeine" life 20 years ago to return to the country life... that after doing 7 to 10 pots (yes 8-10 6-8oz cups) of coffee (European style) a day by myself for 20+ years... so glad to be off the hamster wheel and the addiction where i can enjoy life once more... -- NOTE: No off-list assistance is given without prior approval. *Please keep mailing list traffic on the list* unless private contact is specifically requested and granted. _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Mon Feb 08 2016 - 18:04:59 UTC
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