"JimM" wrote in message ...
'...I should be delighted to learn of an electronic sensor that wil detect
approaching dusk and switch a compact flourescent on for a predetermined
time (preferably not dusk to dawn)...'

Is this the sort of thing you are after

http://www.tlc-direct.co.uk/Products/STNM3000B.html




On a related note I am looking for something that will turn on at dusk
but can be set to turn off at a fixed time. Something that in the
summer will turn on at (say) 10:30 when it gets dark and turn off at
(say) midnight and in the winter will turn on at 5:00 when it gets
dark but will still turn off at midnight. With a timer if it is set
for winter times (seven hours) then in the summer it won't turn off
until 4:30 in the morning.

Just a thought.

Andrew