Comparison

Emerald Observatory for iPad vs iOptron Commander (iOS)

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Read 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.)

About

iOptron Commander (iOS)

Control your iOptron telescope mount remotely using your iOS device. This utility allows for basic functions like slewing to celestial objects, syncing time and location, and managing compatible mount series.

Highlights
  • Remote telescope mount control
  • Slew to stars and deepsky objects
  • Sync time and site from iOS
  • Supports HEM, HAE, HAZ, CEM, GEM series mounts
  • Basic control functions
Features
Read full description

This is an application for owner of iOptron telescope mounts to remote control their telescope mounts via iOS devices. This lite version has some basic function such as slew to famous stars, named deepsky objects, solar system, sync time and site from iOS devices, and etc. Compatible product list: All HEM series All HAE series All HAZ.series CEM120 series CEM70 series GEM45 series CEM40 series GEM28 series CEM26 series SkyHunter

Screenshots

iOptron Commander (iOS)4 screens

Verdict

The call

The clearest difference is review sentiment: Emerald Observatory for iPad at 99% against iOptron Commander (iOS)'s 6%. Emerald Observatory for iPad also leads on rating (4.9 vs 1.8) and ratings volume (102 vs 15). iOptron Commander (iOS)'s advantage is monetization model (free vs paid). 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

Emerald Observatory for iPad holds the better App Store score, 4.9 against 1.8. That said, the two scores are not equally well evidenced: Emerald Observatory for iPad has 102 ratings behind it against 15, so its average is the more settled of the two. Written reviews point the same way: 99% of Emerald Observatory for iPad's written reviews are positive against 6% of iOptron Commander (iOS)'s.

UpkeepUpdate frequency

Emerald Observatory for iPad ships an update every 4 months, iOptron Commander (iOS) every 6 months. The most recent releases landed on November 10, 2026 and November 3, 2026 respectively.

Scorecard4 real differences · 6 level
Emerald Observatory for iPad versus iOptron Commander (iOS): the parameters behind the verdict, then further details
ParameterEmerald Observatory for iPadiOptron Commander (iOS)
PriceFreeFree
Rating4.9 (102 ratings) — better1.8 (15 ratings)
Positive reviews98.7% of reviews — better6.3% of reviews
Number of ratings102 — better15
Update frequencyEvery 4 months — betterEvery 6 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPadiPhone, iPad — better
Requires iOS17.0 — better18.6
Further details — not scored
Size41 MB24 MB
Age rating4+4+
DeveloperBjorn Freeman-Benson成城 徐

Customer experience

Emerald Observatory for iPad

All ratings102 ratings
Positive97.1%
Neutral2.0%
Negative1.0%
Written reviews149 reviews
Positive98.7%
Neutral0.0%
Negative1.3%

iOptron Commander (iOS)

All ratings14 ratings
Positive14.3%
Neutral14.3%
Negative71.4%
Written reviews16 reviews
Positive6.3%
Neutral6.3%
Negative87.5%

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 more
  • 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

iOptron Commander (iOS)

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Emerald Observatory for iPad

No in-app purchases

None

iOptron Commander (iOS)

No in-app purchases

Questions

Is Emerald Observatory for iPad free?
Emerald Observatory for iPad is free to download, with no in-app purchases.
Is iOptron Commander (iOS) free?
iOptron Commander (iOS) is free to download, with no in-app purchases.
Which has better reviews, Emerald Observatory for iPad or iOptron Commander (iOS)?
Emerald Observatory for iPad is rated higher. Emerald Observatory for iPad averages 4.9 out of 5 from 102 ratings, while iOptron Commander (iOS) averages 1.8 from 15 ratings.
Do Emerald Observatory for iPad or iOptron Commander (iOS) have ads?
Neither Emerald Observatory for iPad nor iOptron Commander (iOS) shows ads.
Which is updated more often, Emerald Observatory for iPad or iOptron Commander (iOS)?
Emerald Observatory for iPad ships an update every 4 months, and iOptron Commander (iOS) every 6 months. Most recently, Emerald Observatory for iPad was updated on November 10, 2026 and iOptron Commander (iOS) on November 3, 2026.

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