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 1.4.3

Bug fixes

Ratings and Reviews

4.9 out of 5
42 Ratings

42 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.

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.

jfkaess ,

I keep forgetting how awesome this app is

The latest update now makes the app run without error on ios 10. Still the geekiest app on the app store. Beautiful as well as full of information.

This app is a geek's fantasy. It tells you EVERYTHING about time. Everything. Positions, rising and setting times of sun, moon and first 5 planets. So many things about time that you feel like you've got access to a planetarium and government database!


Emerald Sequoia LLC
18 MB

Requires iOS 8.1 or later. Compatible with iPad.


English, Dutch, French, German, Italian, Japanese, Simplified Chinese, Spanish

Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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