Thanks for your suggestions, Optikon! You wrote:
"You can use an alarm clock to trigger it but why? By the time you get that
figured out you could have built a 24hour timer from a couple of cheap parts (under $5 USD) that can be very low power and run from a battery source for weeks on end.. Lots of examples on the web and on this site."
I thought a travel alarm clock for around $5 would offer a short-cut in may ways. It has a display and would allow me to start up the cycles at any time of the day. If I build a simple timer from parts I would have to start up the system at the exact time of the day when I want all daily photographs to be taken, unless the timer also has a separate internal clock, of course.
Since I am not used to building electronic devices from scratch I tend to look for electronic products that I can modify instead. But if you (or anoyone else) can convince me that it would still be cheaper, faster or better to build the timer from scratch I will certainly consider this option!