Conversion of seconds since J2000 epoch Terrestrial Time to UTC …
2021年12月6日 · Get the J2000 epoch Terrestrial Time in UTC, which seems to be January 1st, 2000 at 11:58:55.816 (see here) Calculate a date and time using such epoch (which is in UTC) and the provided seconds since J2000 epoch Terrestrial Time (since we are now going from seconds since epoch to a date and time, leap seconds need to be taken into account)
What is the difference between GCRS and J2000 frames?
The JPL ephemerides (the underlying basis of JPL Horizons and JPL's SPICE system) treat the J2000 frame and the ICRF frames as equivalent. The ephemerides aren't precise enough to see the difference between the hundredths of arc second difference between the …
Converting J2000 to ECEF? - Space Exploration Stack Exchange
2021年3月27日 · No problem. I can build the matrix myself so long as I know the X, Y, Z rotations needed to transform J2000 into ECEF. If the z axes of J2000 and ECEF are aligned (e.g., if they both coincide with the earth's polar axis), then all I need is the Z rotation from J2000 to ECEF at one moment in time.
fundamental astronomy - Difference between J2000, FK5 and ICRS ...
2019年10月28日 · From what I could gather, the Yale Bright Star Catalog does not explicitly mention the coordinate system it uses, it mentions the epoch to be J2000 frequently though and reports RA, DEC. So, it is my understanding that the coordinate system should be an equatorial one with J2000 as the equinox.
J2000 and J2000.0 difference? - Astronomy Stack Exchange
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Why is there a difference between the ICRS and EME2000
2023年12月1日 · The ICRF was constructed to closely align with the older FK5/J2000 dynamic reference frame – within the uncertainties of that system – while replacing dynamical definitions based on intersecting and moving planes with ones based on the more precisely determined and fixed radio source positions.
Why do J2000 coordinates change with time in Stellarium?
2019年10月19日 · Apparently, Stellarium's "J2000.0" reports the coordinates of stars in J2000 frame, but at the epoch of the date you specify, instead of reporting the coordinates of the star at epoch 2000.0, which can be misleading to say the least. So the difference in J2000 coordinates that you noticed corresponds to the proper motion of the star.
artificial satellite - What was the GPS time at J2000 epoch ...
2023年2月17日 · In total, I get that the GPS time at J2000.0 epoch (GPS time at J2000 epoch - GPS time origin) is 1042 weeks and 561548.816 seconds that is different from the value of 1042 weeks and 561535.816 seconds I get from the website. In the website notes, it is written that the leap second is taken into account for TAI and TT calculations but I do not ...
algorithm - What are the reasons for referring to equinox J2000 or …
2017年5月1日 · Only a little later, iauPlan94 provides the result only for J2000 although Meeus in the chapter dedicated to the paper of J.L.Simon e.al. provides tables with data from their theory for J2000 and the equinox of the date. What would be good reasons for today and the years to come to refer a computation to J2000?
RA and Dec of the Sun at J2000 - Astronomy Stack Exchange
2020年4月9日 · $\begingroup$ @FSimardGIS I'm pretty sure that Izhido is asking for the RA & Dec of the Sun at the exact instant of the J2000 epoch, i.e., on the 1st of January 1, 2000, at 12:00 Terrestrial Time. $\endgroup$ –