Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of thin-film solar maker First Solar (Nasdaq: FSLR) are getting rained on today, down by a whopping 22% at the low, after the company cut its fiscal 2011 guidance and issued a gloomy fiscal 2012 outlook.

So what: First Solar reduced its fiscal 2011 sales guidance from a previous range of $3 billion-$3.3 billion to a lower range of $2.8 billion-$2.9 billion. Fiscal 2012 sales are expected in the neighborhood of $3.7 billion-$4 billion. The figures fall short of analysts' expectations, which call for $3.2 billion in fiscal 2011 and $4.1 billion in fiscal 2012.

Now what: The bottom-line earnings-per-share guidance paints an even darker picture. First Solar sees diluted EPS between $5.75 and $6 for fiscal 2011 and $3.75-$4.25 for fiscal 2012. Analysts are looking for an EPS of $6.88 and $7.42 in 2011 and 2012, respectively, so the midpoint of the 2012 expected profit is 46% lower than what the market was expecting. First Solar attributed the weakness to delays of certain projects due to weather and other factors. It doesn't help that Chinese solar players like LDK Solar (NYSE: LDK) and Trina Solar (NYSE: TSL), among others, are literally killing themselves to gain market share.

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Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool owns shares of First Solar. Motley Fool newsletter services have recommended buying shares of First Solar. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.