Stjernehimmelen er synlig fra observasjonsstedet.

Because Norwegian very often makes compound nouns by joining words together.

• stjerne = star
• himmel = sky / heaven
• stjernehimmel = starry sky / night sky
• stjernehimmelen = the starry sky

This is much more common in Norwegian than in English. Where English often uses several words, Norwegian often prefers one compound word.

In Norwegian, definiteness is usually shown by adding an ending to the noun instead of using a separate word like English the.

Here:

• en stjernehimmel = a starry sky
• stjernehimmelen = the starry sky

The ending -en marks the noun as definite singular for a masculine/common-gender noun.

The same thing happens in observasjonsstedet:

• et observasjonssted = an observation site
• observasjonsstedet = the observation site

The base form is stjernehimmel.

You can break it down like this:

• stjerne = star
• himmel = sky
• stjernehimmel = starry sky
• stjernehimmelen = the starry sky

So the sentence uses the definite singular form of the compound noun.

Because stjernehimmelen is singular common gender, and the adjective is being used predicatively after er.

Norwegian predicative adjectives agree mainly with gender and number:

• common gender singular: synlig
• neuter singular: synlig or sometimes adjectives take -t, but synlig already ends in a way that stays the same
• plural: synlige

So:

• Stjernehimmelen er synlig. = singular
• Stjernene er synlige. = plural

Even though stjernehimmelen is definite, you do not use the attributive definite form here, because synlig comes after er, not before the noun.

Synlig is an adjective, and it means visible.

In this sentence it comes after er, so it describes the subject:

• Stjernehimmelen = the starry sky
• er = is
• synlig = visible

So the structure is basically:

The starry sky + is + visible + from the observation site

Fra means from.

So:

• fra observasjonsstedet = from the observation site

This phrase tells you the point of view or location from which something is visible.

It works similarly to English:

• visible from the balcony
• visible from the road
• visible from the observation site

It is another compound noun:

• observasjon = observation
• sted = place / site
• observasjonssted = observation site
• observasjonsstedet = the observation site

Notice that the first part appears as observasjons- before sted. This kind of linking is normal in compounds.

Also note the gender:

• et observasjonssted = an observation site
• observasjonsstedet = the observation site

So this noun is neuter.

Because Norwegian word order is flexible enough to allow either, depending on what you want to emphasize.

The given sentence is the most neutral:

• Stjernehimmelen er synlig fra observasjonsstedet.

But you could also say:

• Fra observasjonsstedet er stjernehimmelen synlig.

That version emphasizes from the observation site a bit more.

In both cases, Norwegian still follows the V2 rule in main clauses: the finite verb (er) stays in the second position.

Yes. It is a very common and natural pattern.

Examples:

• Fjellet er synlig fra veien. = The mountain is visible from the road.
• Byen er synlig fra toppen. = The city is visible from the top.
• Nordlyset er synlig fra kysten. = The northern lights are visible from the coast.

So [something] er synlig fra [place] is a useful structure to learn.

You could analyze it that way word-for-word, but in natural English you would usually say the starry sky or the night sky.

This is helpful for learners because Norwegian compounds often make sense literally, but the best English equivalent may sound a little different.

So:

• literal breakdown: star-sky
• natural meaning: starry sky / night sky

The endings are:

• -en in stjernehimmelen
• -et in observasjonsstedet

These are the common definite singular endings for:

• many common-gender nouns: -en
• many neuter nouns: -et

A learner should mainly notice that the ending is attached directly to the noun, because that is how Norwegian usually marks the.

So even if pronunciation takes practice, the key grammar point is:

• -en = definite singular common gender
• -et = definite singular neuter