# LSTclock vs Tagtory

The clearest difference is in-app purchases: LSTclock at none against Tagtory's 3. LSTclock also leads on device support (3 vs 1). Tagtory's advantage is update cadence (every 2 days vs every 2 months). On price, ads and iOS requirement there is nothing between them.

Both are free to download. Tagtory sells 3 in-app purchases, starting at $2.99 per month. LSTclock asks for nothing beyond the download.

LSTclock ships an update every 2 months, Tagtory every 2 days. The most recent releases landed on September 9, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | LSTclock | Tagtory |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.8 (10 ratings)](https://appshunter.io/ios/app/lstclock-sidereal-time-clock/id1510148631/reviews)** | — |
| Number of ratings | **10** | — |
| Positive reviews | 54.5% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 days** |
| Monetization | Free | — |
| Size | 15 MB | 12 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | **iPhone, iPad, Apple Watch** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Tsuyoshi Sawada](https://appshunter.io/developer/1510148630) | [ZEYI YAN](https://appshunter.io/developer/1873673136) |

## What reviewers say

### LSTclock

[App page](https://appshunter.io/ios/app/lstclock-sidereal-time-clock/id1510148631)

This utility app displays local sidereal time for registered locations on iOS, iPadOS, and watchOS. It can also calculate sidereal time and Julian Date for any date and time, and sync locations between devices.

**Highlights:** Local sidereal time display, Julian Date calculation, Supports multiple registered locations, Location sync between iPhone and Apple Watch, Date and time specific calculations

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


### Tagtory

[App page](https://appshunter.io/ios/app/tagtory/id6758564754)

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Tagtory Pro Monthly | $2.99 | per month |
| Tagtory Pro Yearly | $24.99 | per year |
| Tagtory Pro Lifetime | $39.99 | one-time |


## Frequently asked questions

### Is LSTclock free?

LSTclock is free to download, with no in-app purchases.

### Is Tagtory free?

Tagtory is free to download, with in-app purchases available.

### Do LSTclock or Tagtory have ads?

Neither LSTclock nor Tagtory shows ads.

### Which is updated more often, LSTclock or Tagtory?

LSTclock ships an update every 2 months, and Tagtory every 2 days. Most recently, LSTclock was updated on September 9, 2026 and Tagtory on September 19, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*