Emerald Observatory for iPad 4+

Emerald Sequoia LLC

    • 4.9 • 63 Ratings
    • $0.99

iPad Screenshots


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 on iOS 4+ if app is not running)
- Eclipse simulator
- Displayed times are synchronized via NTP to "atomic clock" standard
- Uses iPad location, or the latitude and longitude may be set manually

A setting is available to allow the display to stay on continuously.

Tap on the display to move forward by a month, day, year, hour, or minute. A detailed manual for the operation of Emerald Observatory can be found at the "Emerald Sequoia LLC Web Site" listed below, at http://emeraldsequoia.com/eo/

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 iTunes).

(NTP requires Internet access. Like all apps Emerald Observatory can not change the device's internal clock.)

What’s New

Version 1.5.4

Support for iOS 15

Ratings and Reviews

4.9 out of 5
63 Ratings

63 Ratings

RickyMaveety ,

Longtime Favorite

I have had this app for at least six years. It's hard to overstate how much I love it. First, it's beautiful just as a clock, but there is so much more. Sometimes I need a quick UTC reference, and it's there. Sometimes I just want to know what planets are going to be up in the night sky, and it's there. I have watched a few eclipses on it, because they aren't often visible from my spot on earth. I've learned about solar and sidereal time and so much else by exploring this app. It's simply great.

SF Presidio ,

Magnificent Union Of Form And Function

This is a splendid example of application development that is both a useful information center for Astronomy, as well as a beautiful timepiece. The dials are easy to read, and provide a wealth of useful data. Even if you have only a passing interest in the sky above, you will still have an intriguing display of several different ways to measure time. This app is an excellent investment for scholars of any age.

bfaylor ,

My Favorite App

This is one of the few perfects app I have found to date. I have been using it for years and have never had an issue. It gives me a quick view of where the planets are at any given time, has a daily alarm (a beautiful gong sound) that wakes me up every morning and is visually stunning, to boot. Highly recommended if you want to know when the planets rise and set and are a sucker for old style scientific instruments.

App Privacy

The developer, Emerald Sequoia LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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