Desktop Astro Clock vs Momentous Clock
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Desktop Astro Clock
This utility app displays time in various formats, including Julian, Sidereal, and GMT. It offers always-on display options, moon and meteor shower information, and customizable clock configurations. Widgets and a watchOS app are also supported for enhanced functionality.
- Multiple time formats (Julian, Sidereal, GMT)
- Always-on display with battery threshold
- Moon phase and meteor shower information
- Customizable display configurations
- Widget support
- WatchOS app with specialized displays
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Desktop Astro Clock (formally known as: yabc - Yet Another Bedside Clock). This is a clock app that is designed to be run at the desktop, bedside or near a star map. It will display the time without turning off until the battery percentage drops below a user specified value. There are ten predefined, and one user defined display configurations. A single tap of the moon and star icon will bring up a red tinted clock showing the local sidereal time. In settings, you can add a moon display, meteor showers display, change colors, and configure the user defined clock display. Widgets are now supported and can be configured via Widget editing. A watchOS app is now included that displays a red tinted Modified Julian date, GMT Sidereal time, Moon, Moon name, and moon age in days. No ads, ever. Lock screen widgets include rectangular (two clock values look good here) and circular (for the current moon) Features: - Time display in various fixed formats - Time display in a user defined format + color - Always on display until a user specified battery level is reached (iOS) - Moon display with moon transit details and full moon names *(4)* - Meteor Shower information (when visible) with star chart locator - Blue moons are known by the tag [blue moon] added to the full moon name and a blue tint to the full moon image - Super moons are known by the tag [super] added to the full moon name Clock Times: - GMT - Greenwich Mean Time - GMST - Greenwich Mean Sidereal Time - Julian Date - Seconds since noon 1st January 4713 B.C. - LMST - Local Mean Sidereal Time *(3)* - Modified Julian Date - Julian Date - 2400000.5 Predefined displays: - Desk Clock - Day, Time, Date - ISO 8901 - yyyy-mm-ssThh:mm:ss+tz - ISO 8901 GMT - yyyy-mm-ssThh:mm:ssZ - Greenwich Mean Sidereal Time - 'HH'h 'mm's 'ss' - Julian - day.time in seconds since noon 1st January 4713 B.C. - Local Mean Sidereal Time - 'HH'h 'mm'h *(3)* - System Default - based on your iOS settings - Time HH:MM:SS, Month, Day - Time HH:MM - Time HH:MM:SS, Day, Month, Year - User Defined - you pick the format! Widgets (One or more): - Meteor Showers *(1)* - Moon - Moon with details - Moon Names *(4)* - Julian Date *(2)* - Sidereal Date *(2)* - User Defined Clock *(2)* WatchOS App: - Black background, Red tint, brightness adjustable with crown, shows Mofidied Julian Date, GMT Sideral Time, Moon face, Moon name, and Moon age *(3)* *(4)* - Corner complication shows Moon, Modified Julian and Local Sidereal time Lock screen Widgets: - Rectangular for clock values (i.e.: Julian date and Sidereal time) - Circular for the current moon *(1) If no Meteor shower is in progress, just an image is shown* *(2) Widgets do not support real time non-system clocks well. Updates will typically be between 15-60 minutes* *(3) If you select Local Sidereal Mean Time display, you'll also need to enable the setting to allow access to your location information (only needs your longitude for the calculations). Default will be Greenwich England* *(4) If you select Moon names, you'll also need to enable the settings to allow access to your location information (only need to check latitude > 0 for Northeren/Southeren hemishpere). Default will be at the equator*
Momentous Clock
This app transforms your device's clock into a dynamic display of mathematical properties and number theory facts for the current time. It optionally reveals personal number connections from your contacts, all processed securely on your device.
- Computes mathematical properties of time
- Surfaces number theory facts
- Displays time on 16-segment LED screens
- Finds personal number connections in contacts
- On-device contact matching
- Works via Catalyst on Mac
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Time isn’t just 6:31. It’s 631 - a prime! A lucky prime... It’s the combination to the bike lock you had as a kid. It might be the last digits of the cell phone of someone you love. This is a clock for people who notice things like that. Every minute, it: • Computes mathematical properties of the current time • Surfaces number theory facts (prime, factorization, powers, sequences, curiosities) • Scrambles them onto glowing 16-segment LED displays, like your old Speak 'n Spell • Optionally finds personal number connections in your contacts — entirely on device Works great as a Mac app via Catalyst. Contact matching happens entirely on device. No personal data is ever transmitted. Usage analytics (anonymous) are collected to improve the app. If you’ve ever factored timestamps in your head, smiled at 5:12 = 2⁹, or paused at 17:29… This is the clock for you. Make every minute momentous.
Screenshots
Verdict
The clearest difference is rating: Momentous Clock at 5.0 against Desktop Astro Clock's 3.7. Momentous Clock also leads on update cadence (every 6 days vs every 9 months) and iOS requirement (15.1 vs 17.0). On price, ratings volume, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Momentous Clock holds the better App Store score, 5.0 against 3.7. Both are backed by a comparable volume of ratings — 3 and 2 respectively.
Desktop Astro Clock ships an update every 9 months, Momentous Clock every 6 days. The most recent releases landed on June 5, 2026 and June 4, 2026 respectively.
| Parameter | Desktop Astro Clock | Momentous Clock |
|---|---|---|
| Price | Free | Free |
| Rating | 3.7 (3 ratings) | 5.0 (2 ratings) — better |
| Number of ratings | 3 — better | 2 |
| Update frequency | Every 9 months | Every 6 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPad, Apple Watch | iPhone, iPad, iPod |
| Requires iOS | 17.0 | 15.1 — better |
| Further details — not scored | ||
| Size | 416 MB | 24 MB |
| Age rating | 4+ | 4+ |
| Developer | BEHR Consulting International | Tutukain Software, LLC |
Customer experience
Desktop Astro Clock
Momentous Clock
In-app purchases
Desktop Astro Clock
No in-app purchases
Momentous Clock
No in-app purchases
Questions
Is Desktop Astro Clock free?
Is Momentous Clock free?
Which has better reviews, Desktop Astro Clock or Momentous Clock?
Do Desktop Astro Clock or Momentous Clock have ads?
Which is updated more often, Desktop Astro Clock or Momentous Clock?
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