SGP4 propagation start date


I was trying to compare Orekit’s SGP4 with STK to see if the results would have any significant differences, and doing so I realized that in Orekit the start date when you propagate with SGP4 a TLE is the date of the TLE itself, whilst in STK it is possible to use a different start date. Is there any way around this? As in if for instance, my TLE date is 14/09/20 08:45:56:04:456 the propagation date and ephemeris start from 14/09/20 09:00:00:00:000?

Thank you!


You just have to use propagate (start, end)

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And it works also backward, so you can have end earlier than start.
The same is true for all propagators.

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thank you!