Frequency correcting, arduino > other ?

Hi!

Long time no english, hence the stupid topic!

I have standalone stepper controller which has 3.579545MHz chrystal on board.
Testing it for quite a while, it came out to be too slow, not much, but error is
significant. I need 1.002552796 times faster clock, equals to 3.58868285Mhz.
And that is not 100% precise, just to help to keep on track for 4-8 hours.

I don't need precise timing more than every 15-30 seconds, that correction will
do just fine.

Reference time would come from gps, so temperature correction is not needed.

This is telescope mount that needs to be corrected, cheap and usefull way, any
clever ideas that can be taken to design table, would help a lot.

Thanks and cheers,
Kari

Quick and dirty idea...

Could it possible if I put faster chrystal, and slow it down with arduino by shorting it periodically?
Microcontroller in the controller board is Atmel's AT89S51.

Making the clock faster by controlling it with an Arduino sounds too hard task, slowing down
external clock...? How about that?

Cheers,
KAri