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 Chinese solar-cell maker JA Solar (Nasdaq: JASO) raced to a 15.3% gain this afternoon amid average trading volumes.

So what: JA Solar has nothing new to report today, but solar stocks are general market darlings, even among the throng of rising shares. Several large solar installations have just been announced or approved in China and America, and it's easy to get swept along in the sunny enthusiasm.

Now what: Down more than 56% from 52-week highs, JA Solar is one of the most affordable stocks in the already cheap solar industry. Shares trade for a mere 0.28 times trailing sales and 4.5 times forward earnings; just above LDK Solar's (NYSE: LDK) 0.27 and 3.8, respectively, and far below First Solar (Nasdaq: FSLR) on any metric you choose. The deep-discount valuation has struck a chord with our CAPS community, where JA is a four-star stock -- occasionally foraying to the perfect five-star level -- with a 95% approval rating.

Interested in more info on JA Solar? Add it to your watchlist.