I'm not convinced you understand what is meant by a solar timeclock. Sun rise and sunset times can be predicted decades in advance based on the movements of the planets and the sun. Predictions can also be refined to allow for different latitudes.
I am fully aware that a solar time clock is a switching device with pre-programmed on-off times based on sunrise/sunset times which you correctly state can be predicted pretty much for eternity. Some of the funkier models have compensation for BST/leap year, battery backup and offer additional switching and user defined on/off times and days.
A solar eclipse has no bearing on this as it doesn't affect sun rise or sun set.
No, but it does have an impact if CMS does not recognize the event and leaves your lamps off.
A photocell controlled or overridden/fallback lamp/CMS system would automatically activate.
The disadvantaged of just relying on switch times calculated this way, is that weather also affects the perceived brightness at the calculated switch on time. If the solar timeclock has calculated the time point to create a 100 Lux switch point, a wet cloudy day may actual mean the 100 Lux point is reached earlier than the calculated time. Likewise, a clear sunny day may result in 100 Lux point being reached later than the solar prediction.
Combining solar and photocell control allows a more accurate switch point to take this into account, which is what the Lucy system (and all others) allows for.
Point taken & agreed.
What you don't know is how the system is configured in Bolton in terns of Lux level for switching and the control inputs. From your observations, an early switch on scheme has been adopted which as you say could be modified for further energy savings.Casual observation suggests the switching times advance in the as the nights draw in and drop back as the nights draw out. If there was an ambient lux level factored in i would expect at least the odd day when this would not follow. The next time I am outbased at Bolton for a few weeks I will make notes on the lighting up/off times and see if this follows.
I did wonder if using a system of using time only (and erring on the side of caution) would assist in a more accurate energy billing or spread the increase in demand on the grid, but I dont see it. The system could just as easily tell the energy co how many house burned and the lighting load must be relatively insignificant, given that my 10Kw shower is thrown in with impunity and that is equal to the public lighting demand of pretty much the entire housing estate!!!
I also wonder if the system procured is the full system or just a on/off and dimming system. Lamps with dead feeds, failed lamps and persistent dayburners stay unrepaired for months, until reported where upon they are fixed within the usual 2-3weeks - these should all be detected by the system.