The AGC timing reference came from a 2.048 MHz crystal clock. But how accurate was this clock circuit? Note 3 of this schematic: "The value of the follwing components to be determined at unit test" is an indication for trimming the frequency by selecting the value of C2.
The thermistors RT1, RT2 and RT3 look like a temperature compensated DC level. The temperature coefficient of the XTAL might be compensated by the reverse coefficent of selected capacitors.
But how accurate was the derived real time clock of 100 Hz? An error of 10 ppm would be 0.864 seconds a day.
An accurate real time clock was not only important for the timing of course corrections but also for astro navigation using the sextant and telescope.