Jim Varney wrote: >Why does ndot/2 vary from .00000000 to .00000056 but bstar is fixed at 10000-3? >SDP4 uses the bstar drag term -- so why doesn't vary like ndot/s does? > For objects where SDP4 is the model to be used (P>225 min.) ndot/2 is a pseudo-drag term generated to approximate (for a short term) most of the the perturbations modelled by SDP4, so SGP4/SGP programs can give reasonable predictions. -- ------------------------------------------------------------ -- bjorn@tt-tech.se (office) +46-8-59095783 -- -- b_gimle@algonet.se (home) +46-8-7428086 -- -- 59.22371 N, 18.22857 E AND member of : -- -- http://www.algonet.se/~b_gimle SeeSat-L / SeeSat-D -- ------------------------------------------------------------