The broadening of the photospheric lines in ζ Ophiuchu by very rapid rotation allows not ony mapping of its surface velocities and temperature distribution, but makes the star an excellent probe for a profusion of sharp interstellar lines. Being bright, it is a good object for smaller telescopes. Apart from discovering nonradial oscillations in its atmosphere over twenty years ago and a significant temperature differential between pole and equator (the von Zeipel effect), I have recently assisted in the discovery of some 30 lines of interstellar C3 near 405 nm - the first carbon chain to have been found in a diffuse interstellar cloud and at a much higher concentration than expected.