The goal of this bottom trading strategy is to avoid risk and therefore the trade should only be entered if the price stays above $315 on for 24 hours. Reason to buy here: The last low of $315.23 could be a potential "ugly bottom" (a little bit lower than the last bottom at $316.61). And the price is currently at a important of 76.4% (if you connect the 2014 multiple-month low of $275 with the last weeks high of $453.92).
Current price is $323 as of
Wednesday, December 17, 2014, week 51, 23:15 UTC
$317 (we had $317.11) would have been a perfect double bottom with a slightly higher low than the last one ($316.61). At $315 it would have been an "ugly double bottom" with a slightly lower low. But $304.99 seemed to be too low a few days ago to keep the uptrend working, which started at $275 / $300. Now with prices above $317 the long-term uptrend is currently stable again.