I lys av lysforurensningen velger vi annet observasjonssted.

I lys av is a fixed expression meaning in light of, considering, or in view of.

So I lys av lysforurensningen means something like considering the light pollution.

Literally, lys means light, but in this phrase you should learn the whole expression as one unit:

• i lys av = in light of / given / considering

It is a slightly formal expression.

The two instances of lys are doing different jobs:

• i lys av is an idiomatic expression
• lysforurensning is a compound noun meaning light pollution

So even though it may look repetitive, it is not accidental repetition. In English, In light of the light pollution... can also sound repetitive for the same reason.

The ending -en makes lysforurensningen definite: the light pollution.

Compare:

• lysforurensning = light pollution / light pollution in general
• lysforurensningen = the light pollution / a specific, known case of light pollution

The sentence is referring to a particular light-pollution situation that is relevant in the context, so the definite form makes sense.

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

Here, the sentence begins with the prepositional phrase:

• I lys av lysforurensningen

Since that part comes first, the verb must come next:

• I lys av lysforurensningen velger vi ...

So the structure is:

1. fronted phrase
2. finite verb
3. subject

Compare:

• Vi velger annet observasjonssted.
• I lys av lysforurensningen velger vi annet observasjonssted.

This is very common in Norwegian.

Annet means another or a different here.

It changes form to agree with the noun it describes.

The noun observasjonssted is:

• singular
• neuter (et word)

So the correct form is:

• et annet observasjonssted

Compare the forms:

• en annen bok = another book
• et annet sted = another place
• andre bøker = other books

So annet is used because observasjonssted is a neuter singular noun.

This is a very natural question, because many learners expect et annet observasjonssted.

In full, standard Bokmål, et annet observasjonssted is often the form many speakers would expect. The version without et can sound more compressed or formal, and some speakers may find it less natural in everyday speech.

So:

• et annet observasjonssted = a very clear, full form
• annet observasjonssted = shorter, more condensed wording

If you are learning and want the safest everyday version, et annet observasjonssted is a good choice.

Yes. Observasjonssted is a compound noun:

• observasjon = observation
• sted = place/site

Together:

• observasjonssted = observation site / place for observation

Norwegian forms compound nouns very often, much more freely than English. English might write two words, but Norwegian often joins them into one.

Also, the final part of the compound usually determines the grammatical gender. Since sted is neuter, observasjonssted is also neuter:

• et observasjonssted

That is why the sentence uses annet.

Yes, you could, but the nuance changes.

• på grunn av lysforurensningen = because of the light pollution
• i lys av lysforurensningen = in light of / considering the light pollution

På grunn av sounds more directly causal. I lys av sounds a bit more formal, reflective, or analytical, as if the decision is being made after taking the situation into account.

So both can work, but they are not exactly identical in tone.

Velger is the present tense of å velge = to choose.

In Norwegian, the present tense is often used for:

• current actions
• habits
• general statements
• decisions being made now

So here velger vi can mean:

• we choose
• we are choosing
• sometimes even we choose/will choose, depending on context

Norwegian often uses the present tense where English might choose either present continuous or a future expression.

Yes, somewhat.

The sentence sounds more formal or written because of:

• i lys av instead of a simpler phrase like på grunn av
• the somewhat compressed style of annet observasjonssted

A more everyday version might be:

• På grunn av lysforurensningen velger vi et annet observasjonssted.

The original sentence is still understandable, but it has a more official or report-like tone.