English: Map and traveler perspectives of a roundtrip at constant 1 gee proper-acceleration (red arrow in the traveler frame) between the sun (yellow) and a hypothetical star (cyan) 6.9 lightyears away. Proxima Centauri (orange) 4 lightyears from the sun is shown in orange toward the upper left.

From each perspective a year should elapse about every two seconds or every 100/17.4 frames. After each round trip ship-pilots on this shuttle-run will have aged only half as much as colleagues stationed on earth. Other differences include the distance changes between co-moving stars, seen in the traveler frame. Coordinate acceleration (green) seen in the map frame is only significant in the year before and after each launch, while the proper-acceleration (red) felt by the traveler is significant throughout the voyage.

We've added the trace of a light signal initiated from each launch point, but 0.886 map years after launch. This pulse reaches the traveler at the voyage midpoint to remind them to begin deceleration. Note in the map frame that Proxima Centauri sees the turnaround pulse before the destination star does, but that the converse is true in the traveler frame. Nonetheless both observers agree on the sequence of events along any time-like world line.