you can order the 420scope from
www.420science.com . But to be honest, if you dont have one you dont really need one. Alot of the growers on here dont even go by the trichome colors. They wait until the pistils have changed colors about 75% all over the nuggets. Once this happens theyre pretty much at peak potency or maturity, and you can chop chop away. Thats a really great telltale sign of when to cut your bitches down. In the majority of the Cannabis Cultivation books ive read, there is little mention of the trichomes, as far as being able to tell when the plant is ready - they all basically say just wait until the plants pistils have changed color 75% throughout the plant.
But the trichomes are definitely a good way to determine what kind of high you want your plants to have, but you also should have a little bit of experience when trying to determine this way. You should harvest a few plants, each one at a different trichome maturity stage, in order to find out what you like best. It takes a couple grows for you to find the perfect point of maturity for the high you like personally when doing this method. If you cant afford or cant find a scope right now, your more than fine, just pay attention to what the pistils are doin, and youll be just fine man.
good luck with the rest of the grow, id say at least another two weeks, and then you should be good
-K1