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This looks fine for cutoff during sunrise or after a solar eclipse for a couple seconds due to 22M * 0.1uF.

But why do you show a circuit without a purpose or specs to ask a question?

The 22Meg has a very strong purpose as a one-shot and the collector R limit of 10 uA means the Rbe = 26/Ic =  2.5 Meg raises Vbe  to about 10% of the 5V supply.

Any small glass diode or PD with 0.5uA/uW will detect daytime as long as the transistor has a current gain greater than the required current ratio from cutoff to saturation = 46  based on 22M / 0.47M.

The only part that does not do much is the 47 k resistor.

The biggest problem with this circuit is the derivative sensitivity is so high compared to the proportional, that it will generate a 1shot cutoff every time the sun appears suddenly after a cloud but not fog.  (unless that was the intent of this cct)