Circuit description?

Could anyone give me any help with the following circuit?

http://www.piczs.com/is.php?i=25589&img=img004.jpg


Can anybody explain to me exactly how this circuit functions, what it does,
and why were the components chosen i.e. how were the resistor values
calculated etc.
Where it says "solar +ve", this is the positive pole of a small solar
panel.
The circuit works on 2 AA batteries in series (3 volts).
R1, R2, and R3 are all resistors.
The capacitor is a 101. 100pF ceramic disc type.
Two transistors are S8050 type.
Diode is a 1N5819.

I have made a mistake on the drawing, L1 and L2 are inductors, not resistors
as it states.
I think they should be labelled as 470 mH.

The circuit is taken from a solar powered lantern for the garden. It
charges up during the day, and the light comes on when it gets dark. The
light is supposed to last around 8 hours if it has been charged fully.

Thanks for any help.




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