LSTclock: sidereal time clock

Tsuyoshi Sawada Utilities iPhoneiPadiPod touchApple Watch

LSTclock: sidereal time clock is a free Utilities app for iPhone and iPad by Tsuyoshi Sawada. Rated 3.8/5 from 10 ratings. Requires iOS 18.0.

Rating: 3.8; 10 ratings
Price: Free; on the App Store
Size: 22 MB; Age 4+
Updated: Oct 22; 2026 · v10.0

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Screenshots

About LSTclock: sidereal time clock

LSTclock is an iOS/iPadOS/watchOS app that displays the local sidereal time (LST) at registered location(s). On iOS/iPadOS, it can also calculate LST and Julian Date for any date and time. The list of locations can be synced between iPhone and paired Apple Watch(es).

Ratings & reviews

3.8

10 ratings

5 ★ 60% 4 ★ 0% 3 ★ 10% 2 ★ 20% 1 ★ 10%

What’s new

Version 10.0 · Updated October 22, 2026

- Dropped support for iOS/iPadOS 17 and watchOS 10 (sorry for the inconvenience). - Modified the layout of the Main screen to adapt to iPhone Duo (iOS/iPadOS). - Fixed some issues on iOS/iPadOS 27: the "Play/Pause" button behaved unexpectedly; "Share" from Maps app did not work. - UI tweaks. - New icon.

App privacy

The developer, Tsuyoshi Sawada, reported these privacy practices to Apple.

Data Not Collected

The developer does not collect any data from this app.

App details

LSTclock: sidereal time clock is a free Utilities app for iPhone, iPad, iPod touch and Apple Watch, developed by Tsuyoshi Sawada. It is rated 3.8 out of 5 from 10 ratings on the App Store, requires iOS 18.0 or later and is 22 MB to download. It was first released on April 26, 2020 and last updated on October 22, 2026.

Category: Utilities
Rating: 3.8 / 5 (10 ratings)
Price: Free
Version: 10.0
Size: 22 MB
Requires: iOS 18.0 or later
Compatibility: iPhone, iPad, iPod touch, Apple Watch
Languages: English
Age rating: 4+
Released: April 26, 2020
Last updated: October 22, 2026
Developer: Tsuyoshi Sawada

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Alternatives to LSTclock: sidereal time clock

Looking for apps like LSTclock: sidereal time clock? Here are 6 similar apps on the App Store. The highest rated is Custom Word Clock - TextTime (5.0/5), and all 6 are free to download.

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