newtime alters the demanded exposure-time of the observation currently in progress. If the new demanded time is less than the time already exposed, then the exposure ends immediately as if the command was finish.
newtime exp-timewhere exp-time is in seconds.
newtime is sometimes reported as `unsafe'. This stems from a deficiency of the CCD controllers: the exposure timing is implemented in hardware in such a way that it cannot be changed without briefly closing the shutter. Sometimes this shutter movement fails and aborts the exposure. In any case, the shutter movement makes the overall exposure-timing less accurate than would otherwise be the case.