The span of Terrestrial Time over which the ephemeris is evaluated at all:
the years astronomy-engine 2.1.19 itself tabulates, J2000 ± 730,000 days of
TT (0001-04-30T12:00 to 3998-09-03T12:00 TT). That is the range of its Pluto
model's state table; for any other time its source says: "The target time is
outside the year range 0000..4000. Calculate it by crawling backward from 0000
or forward from 4000. ... This is super slow." Beyond the table its other
series diverge as well: on 30000-06-01 the Sun came out 29° off the ecliptic.
Every instant a calculation evaluates, the instant and its speed samples, must
lie inside on the calculation's own ΔT clock, or the call throws RangeError.
With the model ΔT, instants from 0001-05-01T00:00Z to 3998-09-02T00:00Z are
always inside. Being inside is not an accuracy claim: see REFERENCE_SPAN.
The span of Terrestrial Time over which the ephemeris is evaluated at all: the years astronomy-engine 2.1.19 itself tabulates, J2000 ± 730,000 days of TT (0001-04-30T12:00 to 3998-09-03T12:00 TT). That is the range of its Pluto model's state table; for any other time its source says: "The target time is outside the year range 0000..4000. Calculate it by crawling backward from 0000 or forward from 4000. ... This is super slow." Beyond the table its other series diverge as well: on 30000-06-01 the Sun came out 29° off the ecliptic.
Every instant a calculation evaluates, the instant and its speed samples, must lie inside on the calculation's own ΔT clock, or the call throws RangeError. With the model ΔT, instants from 0001-05-01T00:00Z to 3998-09-02T00:00Z are always inside. Being inside is not an accuracy claim: see REFERENCE_SPAN.