Kävellessäni kotiin katselen yötaivasta ja etsin tuttua tähdistöä sekä satelliitteja.

Kävellessäni means roughly “while I am walking” / “as I walk.”
Grammatically, it is:

• the 2nd infinitive in the inessive case of kävellä (to walk)
• plus the 1st person singular possessive suffix -ni (“my / I”).

So:

• kävellä → 2nd infinitive inessive: kävellessä (“while walking”)
• kävellessä
  • -ni → kävellessäni (“while I am walking”).

It introduces a background/ongoing action, similar to English “while walking home, I…”

From kävellä (“to walk”):

1. Take the present stem: kävele-
2. Add the 2nd infinitive -essä/-eessä → käveleessä
3. In actual Finnish this assimilates to kävellessä (the l doubles)
4. Add the possessive suffix -ni → kävellessäni.

You can also say:

• Kun kävelen kotiin, katselen yötaivasta… = “When I walk home, I look at the night sky…”

Kävellessäni kotiin is a bit more compact and often a bit more “written” or stylistically polished, but kun kävelen kotiin is completely correct and very common.

Finnish usually omits personal pronouns when the subject is clear from verb endings or possessive suffixes.

In the sentence:

• katselen (“I look at”) and etsin (“I search for”) are 1st person singular forms
• kävellessäni has -ni, which also indicates “I”.

Because the subject “I” is already marked on the verbs and the infinitive, minä would be redundant. You could add it for emphasis:

• Minä kävellessäni kotiin katselen… (stresses “I, specifically, when I walk home, I look…”)

Finnish has special “local” case forms for koti (“home”):

• koti = basic form (“home” as a word on its own)
• kotiin = illative, “(to) home,” direction towards home
• kotona = inessive, “at home”
• kotoa = elative, “from home.”

In Kävellessäni kotiin…, the idea is movement towards home → therefore kotiin.
Compare:

• Olen kotona. – I am at home.
• Menen kotiin. – I go home.
• Lähden kotoa. – I leave (from) home.

Both come from katsoa (“to look, to watch”), but:

• katson = “I look / I watch” (neutral, one act of looking, or just the basic verb)
• katselen = the frequentative / durative form → “I look (for some time) / I am watching / I’m looking around.”

So katselen yötaivasta suggests a longer, more relaxed, continuous act of looking at the night sky, not just a quick glance. It’s very natural in this context: you’re walking and looking around at the sky.

All three are objects in this sentence, and several things trigger the partitive here:

1. The verbs involved

   • katsella very often takes a partitive object: katselen yötaivasta (“I’m looking at the night sky” in a continuous, unbounded way).
   • etsiä also typically takes a partitive object (see next question).

2. Unbounded / not “all of it”

   • You are not looking at one whole, delimited object from beginning to end; you are just looking at some part / the general expanse of the night sky → yötaivasta (partitive).
   • You are looking for (not necessarily finding) a familiar constellation and (some) satellites → tuttua tähdistöä, satelliitteja (partitive).

So the partitive reflects both the verb requirements and the idea of an ongoing, not-fully-completed or not-fully-delimited action.

Many Finnish verbs of searching, waiting, needing, liking, fearing, etc. tend to require the partitive by default. Etsiä (“to search, to look for”) is one of them.

• Etsin tuttua tähdistöä.
  Literally “I search (for) a familiar constellation” → partitive, because:
  • You are not guaranteed to find it
  • The action is ongoing / incomplete at the time being described.

If you changed the verb to one that implies a completed result, you’d more likely see a total object (often in accusative/genitive):

• Löydän tutun tähdistön. – I (will) find the familiar constellation.

Here the idea is that the event of finding is completed, so the object is treated as a whole, not as something “partial”.

• tuttu tähdistö = “a familiar constellation” (singular)
• In the sentence it becomes tuttua tähdistöä:
  • tuttua = adjective tuttu in partitive singular
  • tähdistöä = noun tähdistö in partitive singular.

In Finnish, adjectives agree with the noun in case and number:

• nominative: tuttu tähdistö
• partitive: tuttua tähdistöä
• plural partitive: tuttuja tähdistöjä, etc.

Satelliitteja is partitive plural of satelliitti (“satellite”). There’s no adjective attached, so only the noun appears: satelliitteja. The plural reflects that you’re looking for several satellites, not just one.

In this sentence, sekä links two objects:

• tuttua tähdistöä sekä satelliitteja
  → “a familiar constellation and satellites,” or “a familiar constellation as well as satellites.”

Points about sekä:

• On its own (as here), sekä ≈ ja (“and”), but often sounds a bit more formal or emphatic.
• In the pair sekä … että …, it means “both … and …”:
  • Etsin sekä tuttua tähdistöä että satelliitteja. – “I look for both a familiar constellation and satellites.”

Here it is simply a slightly more formal “and” connecting two things you are searching for.

Finnish present tense (preesens) can describe:

• something happening right now
• a repeated / habitual action
• general truths.

Kävellessäni kotiin katselen yötaivasta ja etsin… can be understood as:

• habitual: “When(ever) I walk home, I (tend to) look at the night sky and look for a familiar constellation and satellites.”
• or right now: “As I’m walking home (now), I’m looking at the night sky…”

Context would decide which reading is intended. Grammatically, both are possible with the same preesens form.

Yes, you can change the order of the two main verbs:

• Kävellessäni kotiin katselen yötaivasta ja etsin tuttua tähdistöä sekä satelliitteja.
• Kävellessäni kotiin etsin tuttua tähdistöä ja katselen yötaivasta.

Both are grammatically correct. The difference is subtle emphasis:

• In the original, you first paint the picture of katselen yötaivasta (I look at the night sky) and then add etsin tuttua tähdistöä sekä satelliitteja as a more specific thing you do while looking.
• In the alternative, you foreground the searching first.

Finnish word order is fairly flexible, and small changes mostly affect focus and rhythm, not basic meaning.

Yes, here is a compact breakdown:

1. Kävellessäni

   • Base verb: kävellä – “to walk”
   • Form: 2nd infinitive, inessive (-essä) + 1st person suffix -ni
   • Meaning: “while I (am) walking”

2. kotiin

   • Base noun: koti – “home”
   • Case: illative (“to(wards)”)
   • Meaning: “(to) home”

3. katselen

   • Base verb: katsella (frequentative of katsoa) – “to look at, to watch (for some time)”
   • Person/tense: 1st person singular present – “I look (at) / I am looking (at)”

4. yötaivasta

   • Base: yötaivas – “night sky”
   • Case: partitive singular
   • Role: object of katselen – “(the) night sky”

5. ja

   • Conjunction: “and”

6. etsin

   • Base verb: etsiä – “to search for, to look for”
   • Person/tense: 1st person singular present – “I search / I am searching (for)”

7. tuttua

   • Base adjective: tuttu – “familiar”
   • Case/number: partitive singular, agreeing with tähdistöä

8. tähdistöä

   • Base noun: tähdistö – “constellation”
   • Case: partitive singular
   • Role: object of etsin – “(a) familiar constellation”

9. sekä

   • Conjunction: “and / as well as”

10. satelliitteja

    • Base noun: satelliitti – “satellite”
    • Case/number: partitive plural
    • Role: additional object of etsin – “(some) satellites”

So structurally the sentence is:

• [While-walking-I] [to-home] [I-look-at] [night-sky] and [I-search-for] [familiar constellation] and [satellites].