Words for observatory tower such as Tokyo Sky Tree, Umeda Sky Building, etc

Question

What is the word used in Japanese for [Observatory Tower] such as Sky Tree, Umeda Sky Building, or any similar high tower? (not limited to broadcasting tower, but rather place where people can observe scenery from tall building).

Can we use 高い建物? But I think it's too childish to just say "High building" for [Observatory Tower].

Answer 1

The direct translation of "observatory tower" is 展望タワー or 展望塔. Use it if the main purpose of the tower is having an observation deck and attracting tourists. The number of "pure" 展望タワー is not large, but such towers include Kyoto Tower, Tsūtenkaku and Chiba Port Tower.

Many towers and skyscrapers have multiple purposes. Tokyo Sky Tree and Eiffel Tower are also 電波塔 (broadcasting tower), but they can safely be called 展望タワー/塔 because tourism is obviously one of the largest purposes. Umeda Sky Building and Empire State Building are usually not called 展望塔/タワー/ビル even though they have observatory decks.

Other expressions:

• (超)高層ビル: a skyscraper (may or may not have an observatory deck)
• 複合ビル: (lit. "compound building") a building with multiple purposes (eg, office, hotel, shop, residential, restaurant, observatory...) like Umeda Sky Building and Burj Khalifa
• 展望台: an observation deck/platform (built upon a tower/building, or on a mountain road)
• 超高層ビルの展望台: "an observation deck on a skyscraper"
• 展望台のある超高層ビル: "a skyscraper that has an observation deck"
• 電波塔: a broadcast tower/mast
• 見張り台/見張り塔: "observatory tower" for military/guarding purposes.

Answer 2

Just the word "observatory" as you have in your examples for Sky Tree and Umeda Sky Building would be 「展望台」.

But if you want to be more specific about the kind of building or observatory, you need to put in a little more information, because a 展望台, just like an "observatory" is not necessarily a tall building or tower. It could also be on a mountain for example.

• 高層ビルの展望台 - fits for any observatory in a tall building (like Umeda Sky Building, not a tower like Sky Tree)
• タワーの展望台 - "tower observatory"
• 山頂の展望台 - observatory on the top of a mountain

However, 展望台 are only for looking at beautiful scenery.
If you want to use "observatory" to mean "weather observatory" or astronomical observatory" then you should say 「観測所{かんそくじょ}」.

Answer 3

I think you can try:

• 見晴{みは}らしがいい場所
• 見晴らし台
• 展望台{てんぼうだい}