I was invited late to this party, but I've been working on a presentation (of which "elapsed time" is
not the subject) -- so I dispose of the subject of "relativistic elapsed time" with this single slide:
![](http://www.microlith.com/AnIso/Rev7Renderings/ReferenceFrames.jpg)
(This imqge is a "privileged draft", is not for copying or further publication, and is subject to change...)