Learn French: Avec ce télescope, on voit de nouvelles constellations. - With this telescope, we see new constellations.

This is the focus of this lesson! Normally, the plural indefinite article for "some" is des. However, when a plural adjective comes right before a plural noun, des is reduced to de. Since the plural adjective nouvelles comes before the noun, we must use de.

Why is the adjective nouvelles placed before the noun instead of after?

Most French adjectives go after the noun, but a handful of common adjectives come before it. A helpful trick is the BAGS acronym, which stands for Beauty, Age, Goodness, and Size. Because "new" falls under Age, nouvelles is placed before constellations.

Why use ce for "this" here? Shouldn't it be cet?

Télescope is a masculine noun starting with a consonant, so it takes the standard masculine demonstrative adjective ce. You only use cet when a masculine noun starts with a vowel or a mute H (for example, cet animal). If it were a feminine noun, you would use cette.

The translation says "we see," but doesn't on mean "one"?