I lys av skydekket bruker vi ikke kikkerten.

Because i lys av is a fixed expression meaning in light of, considering, or given. It introduces the reason or context for the rest of the sentence.

So I lys av skydekket sets up the situation first, and then the sentence tells you what happens because of that situation.

This expression is a bit more formal or written-sounding than everyday alternatives like på grunn av.

This is because Norwegian main clauses follow the V2 rule: the finite verb must be in the second position.

Here, the first position is already taken by the fronted phrase:

I lys av skydekket + bruker + vi + ikke + kikkerten

If you started directly with the subject, it would be:

Vi bruker ikke kikkerten.

But once you move I lys av skydekket to the front, the verb has to come right after it:

I lys av skydekket bruker vi ikke kikkerten.

In a normal main clause, ikke usually comes after the finite verb and often after the subject if the subject follows the verb.

In this sentence, the order is:

• fronted phrase: I lys av skydekket
• finite verb: bruker
• subject: vi
• negation: ikke
• object: kikkerten

So ikke is in the normal place for a Norwegian main clause with inverted word order.

Compare:

• Vi bruker ikke kikkerten.
• I lys av skydekket bruker vi ikke kikkerten.

Skydekket is the definite form of skydekke, a noun meaning cloud cover.

It is a compound noun:

• sky = cloud
• dekke = cover, layer, covering

So:

• et skydekke = a cloud cover
• skydekket = the cloud cover

The -et ending shows that it is a neuter noun in the definite singular.

Kikkerten is the definite singular form of kikkert.

• en kikkert = a pair of binoculars / a binocular / a scope
• kikkerten = the binoculars / the binocular / the scope

The definite form is used because the sentence refers to a specific binocular-related object that is understood in the situation.

In English, we often say the binoculars, but Norwegian commonly uses kikkert as a singular noun.

This is a very common thing for English speakers to notice.

In Norwegian, kikkert is usually treated as a singular noun, even when English uses the plural binoculars.

So Norwegian says:

• en kikkert
• kikkerten

while English often says:

• a pair of binoculars
• the binoculars

So the grammar is different, even if the meaning is the same.

Yes. Bruker is the present tense of å bruke.

• å bruke = to use
• bruker = use / are using / do use, depending on context

Norwegian present tense can cover several meanings that English expresses differently:

• we use
• we are using
• sometimes even a near-future sense, depending on context

So the exact English translation depends on the situation, but grammatically it is the Norwegian present tense.

Yes, you could, but the nuance is a little different.

• på grunn av = because of, due to
• i lys av = in light of, considering, given

På grunn av skydekket bruker vi ikke kikkerten sounds more direct and causal.

I lys av skydekket bruker vi ikke kikkerten sounds a bit more formal and evaluative, as if you are making a decision based on the conditions.

So both can work, but i lys av has a slightly more formal tone.

Usually, no.

In standard Norwegian, a short introductory phrase like this normally does not need a comma:

I lys av skydekket bruker vi ikke kikkerten.

A comma might sometimes appear for stylistic reasons in certain kinds of writing, but in ordinary standard usage, leaving it out is the normal choice.

It is best to learn i lys av as a set phrase.

Even though the words individually are simple:

• i = in
• lys = light
• av = of

the whole expression functions idiomatically as in light of or considering.

So for learners, it is safest to remember it as one chunk:

i lys av + noun phrase

For example:

• I lys av værmeldingen ...
• I lys av situasjonen ...
• I lys av resultatene ...

That will sound much more natural than trying to build the phrase from scratch each time.