Emerald Observatory for iPad vs Desktop Astro Clock
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Emerald Observatory for iPad
This app provides a comprehensive astronomical display on a single screen, offering detailed information about celestial bodies and timekeeping. It features a heliocentric orrery, rise and set times, twilight information, and moon phase details. Users can navigate through time and set alarms for astronomical events.
- Astronomical information display
- Heliocentric orrery
- Rise and set times for Sun, Moon, planets
- Twilight times
- Moon phase and orientation
- World map of day/night regions
- Eclipse simulator
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Emerald Observatory displays a wealth of astronomical information all on one screen, in a unique but understandable format. Information includes: - 12- and 24-hour ordinary clock time - Times of rise and set for the Sun, the Moon, and the 5 classical planets - Times of the beginning and ending of twilight - Heliocentric orrery (display of the planets in orbit around the Sun) - Altitude and azimuth for the same bodies (one body at a time) - Current phase and apparent orientation and relative size of the moon - Current regions of day and night on a world map - The Equation of Time, solar time, UTC time, and sidereal time - Month, day, year, and leap-year indicator - Daily alarm (delivered as local notification if app is not running) - Eclipse simulator - Displayed times are synchronized via NTP to "atomic clock" standard, or can be set manually - Uses iPad location, or the latitude and longitude may be set manually A setting is available to allow the display to stay on continuously. If you are having any trouble with the application whatsoever, please see our FAQ on the support page listed below and then contact us through that page if your problem is not resolved. We take pride in responding promptly to all support email requests but we can't fix it if you don't report it (and we have no way to respond to Customer Reviews on the App Store). (NTP requires Internet access. Like all apps Emerald Observatory can not change the device's internal clock.)
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*
Screenshots
Verdict
The clearest difference is rating: Emerald Observatory for iPad at 4.9 against Desktop Astro Clock's 3.7. Emerald Observatory for iPad also leads on ratings volume (99 vs 3). Desktop Astro Clock's advantage is monetization model (free vs paid) and device support (3 vs 1). On price, update cadence, 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.
Emerald Observatory for iPad holds the better App Store score, 4.9 against 3.7. That said, the two scores are not equally well evidenced: Emerald Observatory for iPad has 99 ratings behind it against 3, so its average is the more settled of the two.
Emerald Observatory for iPad ships an update every 5 months, Desktop Astro Clock every 9 months. The most recent releases landed on November 1, 2026 and October 30, 2026 respectively.
| Parameter | Emerald Observatory for iPad | Desktop Astro Clock |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (99 ratings) — better | 3.7 (3 ratings) |
| Positive reviews | 98.7% of reviews | — |
| Number of ratings | 99 — better | 3 |
| Update frequency | Every 5 months — better | Every 9 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPad | iPhone, iPad, Apple Watch — better |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 19 MB | 416 MB |
| Age rating | 4+ | 4+ |
| Developer | Bjorn Freeman-Benson | BEHR Consulting International |
Customer experience
Emerald Observatory for iPad
Desktop Astro Clock
Bugs and requests
Emerald Observatory for iPad
Requested features
14 requests- Port to screen wallpaper
- Large wall clock version
- Apple TV version
- Support for Uranus, Neptune, and Pluto
- iPhone and Apple Watch versions
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- Alarm functionality
- Screen dimming for night use
- Numeric display of values
- Switch altitude/azimuth by touching planet
- Push notifications for specific events
- Custom chime sounds for events
- Round earth display to match moon display
- iPad version of Chronometer iPhone app
- Tutorial mode or on-screen help
Desktop Astro Clock
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Emerald Observatory for iPad
No in-app purchases
Desktop Astro Clock
No in-app purchases
Questions
Is Emerald Observatory for iPad free?
Is Desktop Astro Clock free?
Which has better reviews, Emerald Observatory for iPad or Desktop Astro Clock?
Do Emerald Observatory for iPad or Desktop Astro Clock have ads?
Which is updated more often, Emerald Observatory for iPad or Desktop Astro Clock?
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