Learn Dutch: Wij boekstaven wat we door de telescoop zien. - We document what we see through the telescope.

Boekstaven is an inseparable "back-formation." Instead of being made by sticking a loose prefix onto an existing verb, it was created backwards from the old noun boekstaaf (meaning a letter or character). Because it was born from a single noun, it acts as a single, glued-together verb. You will never say wij staven boek.

How do you form the past tense and past participle of boekstaven?

Back-formations almost always conjugate as regular (weak) verbs, even if part of the word looks strong. Because the verb stem ends in a v (boekstav-), it gets a d: the past tense is boekstaafden and the past participle is geboekstaafd. Since it is inseparable, the ge- goes at the very beginning, not in the middle.

Why do we use wat in this sentence instead of dat?

In this sentence, wat translates to "that which" or "the things that." You must use wat because there is no specific noun earlier in the sentence for it to refer back to. If you were referring to a specific "het" word, like "the object that we see" (het object dat we zien), you would use dat.

Why is the verb zien pushed all the way to the end?