<img src="https://i.sstatic.net/gBIy8.jpg" alt="power outlet, 2 timers, light bulb">
<br>
Two motorized 24-hour
[light timers](https://en.wikipedia.org/wiki/Time_switch)
are [daisy
chained](https://en.wikipedia.org/wiki/Daisy_chain_%28electrical_engineering%29)
between a power outlet and a light bulb.

For these timers, devise schedules and choose initial times
that produce the following repeated 9-hour lighting pattern,
with the largest possible whole number $d$ less than&nbsp;9,
beginning when the outlet's power is switched on.

&nbsp;&ensp;&hairsp;&hairsp;   Light is on for $\:d~$ hours,$~$ off for $\,9\,$&ndash;$\:d~~$ hours, <br>
&nbsp;&emsp;&emsp;&emsp;&emsp;          on for $\:d~$ hours,$~$ off for $\,9\,$&ndash;$\:d~~$ hours, <br>
&nbsp;&emsp;&emsp;&emsp;&emsp;          on for $\:d~$ hours,$~$ off for $\,9\,$&ndash;$\:d~~$ hours, <br>
&nbsp;&emsp;&emsp;&emsp;&emsp;          $~\,\vdots$


**If you are unfamiliar with these timers**

Each timer repeatedly cycles through
its schedule of 24 intervals that last an hour each.
<br><sup><sup></sup></sup>
&bull;$~$ A circular dial determines the current point in the schedule
<br><sup><sup></sup></sup>
&bull;$~$ A motor rotates the dial to advance through its schedule
          whenever power is supplied to the timer
<br><sup><sup></sup></sup>
&bull;$~$ You may initially set the dial to any minute of any interval
<br><sup><sup></sup></sup>
&bull;$~$ You preset each interval to ON or OFF
<br><sup><sup></sup></sup>
&bull;$~$ When the dial is in an interval that was set to ON,
          the timer acts as a direct connection for power to flow
          to whatever is plugged into the timer
<br><sup><sup></sup></sup>
&bull;$~$ When the dial is in an interval that was set to OFF,
          the timer does not provide a power connection
<br><sup><sup></sup></sup>
&bull;$~$ The resulting ON and OFF durations could be fractions of an hour
          if the timer is set to begin within an interval or
          if incoming power is interrupted during an interval

The first timer is plugged into the outlet.
<br><sup></sup>
&bull;$~$ It runs nonstop once the outlet is switched on
<br><sup></sup>
&bull;$~$ It supplies power&mdash;&hairsp;but only when its dial is in
          an ON interval&hairsp;&mdash;&hairsp;to the second timer

The second timer has the light bulb plugged into it.
<br><sup></sup>
&bull;$~$ It advances through its schedule
          only when the first timer supplies power
<br><sup></sup>
&bull;$~$ It lights the bulb, but only while powered by
          the first timer and when its dial is in an ON interval


**Related puzzles**
<br>
[Halve time with two timers](http://puzzling.stackexchange.com/q/25606/18129)
<br>
[Day and night of the two timers](http://puzzling.stackexchange.com/q/25812/18129)
<br>
[Third timer's a charm](http://puzzling.stackexchange.com/q/33882/18129)

<sup>
(This puzzle is directly from an actual botany experiment)
</sup>