Planet X Coordinates, Clarified 2

In case the issue of J2000 or B1950 is dredged up again by Dave, who
tends to have amnesia.  Questions on using J2000 were asked in May:

In Article <KR%[email protected]> David Tholen wrote:
> are those positions mean of date, apparent, J2000, B1950,
> or something else? Are the positions geocentric or
> topocentric to some particular location?
> Are the times Coordinated Universal Time,
> Terrestrial Time, Barycentric Dynamical Time,
> or for some particular time zone? Should one
> assume "May 23" means May 23.00000?
> And you do realize that the positions do not fit any
> orbit, do you?

In Article <[email protected]> John Latala wrote:
> An epoch is a reference time used to fix or set the coordinates.
> What's happening is that the Earth moves in a few unusual
> ways and to 'cancel' out some of that motion they assign an
> epoch. ... Common epochs are B1950 and J2000.

And on May 7, 2001, in Article <[email protected]>
I answered:

&&&&&&&&&&&&&&&&&&&&&&&&&&&&

I have an astronomy book dated 1991, and it states that star charts and
catalogs are being redone at that time into J2000.  As the year 2000 is
behind us, I presume that coordinates given for 2001, by the Zetas are
in accordance with the J2000 star charts.  I’ll ask:

    Right you are.
        ZetaTalk™

Well, and the three observatories did not ASK this information when
given the coordinates.  Why not, if it is key?  I would think that
RECENT coordinates given do not need this epoch clarification.  Kind of
a dumb question, when you think about it.  How would coordinates given
in 2001 BE in accordance with 1950 earth wobble?  You’d only need to
know the epoch if you were dealing with a, for instance, 1961 RA and Dec
given, right?  Then you’d need to convert, right?  Dear David Tholen,
once again you’re over there in the corner, sorting your paper clips,
muttering to yourself about details that don’t even apply, missing the
whole point of the conversation!