Build a high quality telescope from scratch I am interested in building a high quality portable telescope from scratch in an attempt to better understand how telescopes work. What kind of materials do I need? How would I go about putting the telescope together? Are there any online guides that you can recommend?
Amateur telescope making (ATM) is a popular past-time for astronomers.

You can grind your own mirror, or you can buy ready-made mirrors. 

You can coat your mirrors with silver using chemical solutions yourself, or have a coating of aluminium applied using a vacuum chamber by an outfit offering such a service.

The main materials are a thick round slab of glass, usually Pyrex, and a smaller elliptical flat mirror. Using this you can make a Newtonian reflector. The support tube or structure for the mirrors can be one of a huge variety of designs, or you can be inventive yourself.

There are websites to guide you in this, such as Mel Bartel's, Stellafane, and AmateurTelescopeMaker.com.