<div dir="ltr"><div><div><div><div><div><div><div><div><div><div>Thanks Arnold.. <br></div>I agree with how you described just about everything in terms of the current types.<br></div>The one part that causes me confusion is below..<br><br></div>So.. timeOrigin <br> 1) should be provided in the Frame ONLY if the referring coordinate is a TimeOffset.<br></div> 2) is expressed as a non-TimeOffset TimeStamp<br></div> 3) 'referenced to the same TimeFrame' (as the original TimeOffset?) <<< this I don't understand<br></div> If the TimeOffset.frame contains a timeOrigin expressed as a MJD<br></div> and that MJD refers to the same frame, that would be an MJD referring to <br></div> a frame with a timeOrigin, which opposes #1.<br></div> If, the MJD refers to a different frame (with no timeOrigin), then you have a short train of types/frames.<br><br></div>You are asserting that if I have 2 TimeOffset-s with different offsets, they are in different frames.<br><div><div><div><div><div> T1{ time=t1, frame=TimeFrame1{ timescale='TT', refPosition="TOPOCENTER", timeOrigin=MJD{ date=50814.0, frame=TimeFrame1} } }<br></div><div><div><div><div><div>
<div> T2{ time=t2, frame=TimeFrame2{ timescale='TT', refPosition="TOPOCENTER", timeOrigin=MJD{ date=51179.0, frame=TimeFrame2} } }<br><br></div><div>or maybe<br></div><div> TimeFrame0{ timescale="TT", refPosition="TOPOCENTER"}<br></div><div>
<div> T1{ time=t1, frame=TimeFrame1{ timescale='TT',
refPosition="TOPOCENTER", timeOrigin=MJD{ date=50814.0,
frame=TimeFrame0} } }<br></div><div><div><div><div><div>
<div> T2{ time=t2, frame=TimeFrame2{ timescale='TT',
refPosition="TOPOCENTER", timeOrigin=MJD{ date=51179.0,
frame=TimeFrame0} } }<br></div></div></div></div></div></div>
<br></div><div><div><div><div><div>but they are NOT in the same frame, with different offsets..<br>
<div> TimeFrame0{ timescale="TT", refPosition="TOPOCENTER"}<br></div><div>
<div> T1{ time=t1, frame=TimeFrame0, timeO=MJD{ date=50814.0,
frame=TimeFrame0} }<br></div><div><div><div><div><div>
<div> T2{ time=t2, frame=TimeFrame0, timeO=MJD{ date=51179.0,
frame=TimeFrame0} }<br></div></div></div></div></div></div>
</div>
<br></div></div></div></div></div>
Mark<br><br></div><div><div><br><div><div><div class="gmail_extra"><div class="gmail_quote">On Thu, Apr 12, 2018 at 2:49 PM, Arnold Rots <span dir="ltr"><<a href="mailto:arots@cfa.harvard.edu" target="_blank">arots@cfa.harvard.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><div><br></div>The time stamp can be specified as:<br></div>JD (no units required)<br></div>MJD (no units required)<br></div>ISO-8601 (no units required)<br>TimeOffset (units required, as well as a value for timeOrigin in the frame)<br></div><br></div>The timeOrigin should expressed as a TimeStamp (JD, MJD, or ISOTime, but NOT TimeOffset),<br></div>referenced to the same TimeFrame.<br><br></div>So, yes, this is recursive, but there are strict constraints on the timeOrigin which should prevent runaway looping.<br><br></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></blockquote></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>