exactly, $8 from radioshack
http://www.radioshack.com/product/index.jsp?productId=2179604
60x-100x magnification, has worked for years with me.
your plants could be ripe anywherre between 15 and 60 days depending on strain
I totally agree. That is ultimately the stuff that melts your brain. Once the crystals (trichomes) start looking like little Hiroshima bombs, and say half of the hairs turn orange, and the calyxes....where the hairs (pistils) come out start getting round and seed shaped, then consider it in at least the beginning of the final stages.
Your plant gives off a first impression of probably a sativa dominant strain so I would call it at least 3 more weeks. And as long as the plant can stay decently healthy, these last weeks are when your weight is gained. I don't want to guess at %'s of gain, but it is significant. Even chopping a week earlier than normal can affect a yield substantially.
I am going to recommend you get away from the Miracle Gro. Some say it works well, but there are many better products you could use that are probably as economical, but more effective. If it works and you can manage, and feel comfortable with it, by all means use it.
Just my opinion though, but the buds look yummy, I think most will agree on that.