Emerald Observatory for iPad vs D
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
Read full descriptionHide full description
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.)
D
Easily set and track important dates, such as D-Day. This utility app helps you monitor the remaining time until your specified events.
- Set D-Day
- Check remaining time
- Event tracking
- Simple interface
Read full descriptionHide full description
Set D-Day and check remain.
Screenshots
Verdict
The clearest difference is monetization model: D at free against Emerald Observatory for iPad's paid. D also leads on update cadence (every 5 weeks vs every 5 months) and device support (3 vs 1). Emerald Observatory for iPad's advantage is ratings volume (99 vs 1). On price, rating, 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.
On the App Store both sit at effectively the same score — 4.9 for Emerald Observatory for iPad against 5.0 for D. That said, the two scores are not equally well evidenced: Emerald Observatory for iPad has 99 ratings behind it against 1, so its average is the more settled of the two.
Emerald Observatory for iPad ships an update every 5 months, D every 5 weeks. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.
| Parameter | Emerald Observatory for iPad | D |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (99 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 98.7% of reviews | — |
| Number of ratings | 99 — better | 1 |
| Update frequency | Every 5 months | Every 5 weeks — better |
| 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 | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Bjorn Freeman-Benson | Si-Wan Yoon |
Customer experience
Emerald Observatory for iPad
D
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
Show 9 moreShow fewer
- 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
D
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Emerald Observatory for iPad
No in-app purchases
D
No in-app purchases
Questions
Is Emerald Observatory for iPad free?
Is D free?
Which has better reviews, Emerald Observatory for iPad or D?
Do Emerald Observatory for iPad or D have ads?
Which is updated more often, Emerald Observatory for iPad or D?
Other comparisons
