... Tonight's Sky . ... Observing . ... Observing springtime deep-sky objects with a large telescope . ... Astronomy 101 . ... When you re finished reading this article, refer back to recent issues of Astronomy and carefully read telescope reviews (subscribers can read them online in the Astronomy.com Equipment Review Archive ). ... By doing this, you ll learn what s important to observers when they use a telescope. ... The three main types of telescopes use lenses, mirrors, or a combination of both. ...