Solar day: result of relation between Earth and Sun.
In FE model Sun makes one full circle every 24 hours.
Sidereal day: result of relation between Earth and random distant star.
In FE model stars (dome) make one full circle every "3m 56secs less than 24 hrs".
Such behavior in FE model have problems explaining many other observations,
but if we don't go further than Solar and Sidereal day, it could work.