Setting a 555 for 45Hz

So I got the equation:

f = 1 / ( 0.693 x C (R1 + 2 x R2))

I am trying to run a 4017 to run a repeating sequential output to 3 high speed 9V solenoids (15Hz each). So, I am planning on running it off a 555 set at 45Hz.

How do I choose a capacitor? The solenoids were pulled from setups that used 10V 6800uf capacitors, but I assume thats just to drive the solenoids and is separate from the function of the ICs. Also, when choosing resistors, would I try to use as low a value resistor as possible?

Any help greatly appreciated.

-Chris Placzek

If this is related to yesterday's 45 Hz 555 thread, it should be continued there.

OK im continuing everything related to that thread in that thread, unless otherwise required. For this, I went with a 0.1uF cap, a 10k at R1, and a 200k at R2, to yield 35Hz (a better starting point than 45Hz for this project).

Don't expect a great degree of accuracy, electrolytic capacitors have a typical tolerance of 20% so the frequency could be anywhere between 36Hz and 54Hz before the tolerance of the other components is even considered.