Learn Hardcore Russian: Телескоп уже поставлен у окна, и наблюдение за звёздами начато. - The telescope has already been placed by the window, and the observation of the stars has begun.

Instead of a full form like Телескоп есть поставлен у окна, Russian simply says Телескоп уже поставлен у окна.
The form поставлен already tells you that something has been put/placed; Russian does not need an extra “is”.

So the idea “The telescope is already placed by the window” is expressed without an explicit “is.”

What exactly is поставлен? Is it a verb, an adjective, or something else?

Поставлен is a short-form passive participle from the perfective verb поставить (to put, to place upright).

Full (long) participle/adjective: поставленный телескоп – the telescope that has been placed.
Short form: Телескоп поставлен – The telescope is (has been) placed.

Key points:

Short-form passive participles typically appear after the noun they describe and often translate as “is/was done”:
- дверь закрыта – the door is closed
- работа выполнена – the work is done
They have a strong resultative flavor: the action is completed and we’re focusing on the result (it’s now standing there).

So Телескоп уже поставлен у окна focuses on the result: the telescope has been placed and is now by the window.

What’s the difference between Телескоп уже поставлен у окна and Телескоп уже стоит у окна?

Both are correct, but they highlight different things:

Телескоп уже поставлен у окна
- Uses поставлен (from поставить, perfective).
- Emphasizes the completed action of placing it: it has already been put there.
- Slightly more formal / “result-of-an-action” feel.
Телескоп уже стоит у окна
- Uses the verb стоять (to stand).
- Describes the current state: the telescope is (currently) standing by the window.
- Sounds more neutral, everyday.

In English we might choose “has already been placed” vs. “is already standing.” Russian makes a similar nuance.

How is the structure наблюдение за звёздами начато built grammatically?

It’s built as:

наблюдение – a verbal noun meaning “observation” (from наблюдать – to observe).
за звёздами – a prepositional phrase with за + instrumental, meaning “(observation) of the stars / observing the stars”.
начато – a short-form passive participle from начать (to start, to begin), neuter singular.

So structurally it is:

[noun] + [prepositional phrase] + [short-form participle]
наблюдение за звёздами начато
“The observation of the stars has been started.”

This is a compact, somewhat formal way of saying something like:

Мы начали наблюдать за звёздами. – We started to observe the stars.

Why is it начато and not началось? What is the difference?

Both начато and началось are possible in Russian, but they are different forms:

начато – short-form passive participle of начать.
- Used with a noun: наблюдение начато – the observation has been begun / is started.
- Sounds more formal, bookish, result-focused.
началось – past tense, neuter, of the verb начаться (to begin, to start).
- Treats the process as an event:
  - наблюдение началось – the observation started / began.
- Feels more like a normal past-tense verb, often more neutral/colloquial.

So:

наблюдение за звёздами начато – formal, focuses on the completed act of initiating the observation.
наблюдение за звёздами началось – more neutral: the observation of the stars has begun/started.

Why is it за звёздами (instrumental case)? I thought за usually took the accusative.

The preposition за can take either accusative or instrumental, depending on meaning:

за + accusative – motion “to a place behind/beyond” or “for the purpose of getting”:
- идти за хлебом – to go for bread
- зайти за дом – to go behind the house
за + instrumental – a static position “behind/beyond” or a sphere of activity/observation:
- сидеть за столом – to sit at the table
- наблюдать за звёздами – to observe the stars

The verb наблюдать uses the pattern:

наблюдать за + instrumental – to watch/observe someone/something

So:

наблюдение за звёздами literally: “observation over the stars,” but idiomatically “observation of the stars.”
That’s why звёздами is in the instrumental plural.

What does у окна literally mean, and why is it окна (genitive) and not окно?

The preposition у means “by, at, near (something)” and it always takes the genitive case.

окно – nominative singular (window)
окна – genitive singular (of the window → “by the window” with у)

So:

у окна = by/at the window.
Literally: “at (the location of) the window.”

Comparable expressions:

у окна – by the window
возле окна, около окна – near the window (also genitive)
рядом с окном – next to the window (here окном is instrumental after с)

But with у, genitive is mandatory, so у окна is the correct form.

Could уже be placed somewhere else? Would that change the meaning?

In Телескоп уже поставлен у окна, уже modifies the whole idea of the telescope being placed; the main meaning is “already”.

Other possible placements:

Уже телескоп поставлен у окна.
- Grammatically possible but sounds unusual/marked, emphasising “already” or contrast (e.g., “Already the telescope is placed by the window (even though we just started)”).
Телескоп поставлен уже у окна.
- This sounds odd and might suggest contrast about where it’s placed, but in practice, native speakers would rarely say this.

In everyday speech, the natural place is exactly as in the example:

Телескоп уже поставлен у окна.

So, while Russian word order is flexible, moving уже often creates emphasis or may sound unnatural here.

Why is there a comma before и? Are there two separate clauses?

Yes, there are effectively two clauses joined by и:

Телескоп уже поставлен у окна
(и) наблюдение за звёздами начато

Both are independent statements about what has been done. In Russian, when и joins two independent clauses, a comma is normally used before и:

Телескоп уже поставлен у окна, и наблюдение за звёздами начато.

Note that the second clause omits the subject (there is no наблюдение at the beginning), but it is understood from the phrase that follows: наблюдение за звёздами (есть) начато. This kind of subject-ellipsis is common, and the comma rule still applies because the clauses are parallel in structure and meaning.

Does this sentence sound formal? How would you say it in more everyday Russian?

Yes, the use of short-form passive participles (поставлен, начато) and the abstract noun наблюдение makes the sentence sound fairly formal or bookish, like something from written instructions or a report.

A more everyday, conversational version could be:

Телескоп уже стоит у окна, и мы начали наблюдать за звёздами.
- стоит – is standing (neutral, colloquial)
- мы начали наблюдать – we started to observe (normal verb phrase instead of the noun наблюдение)

Both versions are correct; the original is just more official/impersonal in tone.