CHAPTER I PAGE
THE SELECTION AND TESTING OF A GLASS 1
How to get a good telescope--Difference between reflectors and refractors--How a telescope is made achromatic--The way to test a telescope on stars.
THE SELECTION AND TESTING OF A GLASS 1
How to get a good telescope--Difference between reflectors and refractors--How a telescope is made achromatic--The way to test a telescope on stars.