# UTC Orbit > Time conversion utility for orbital elements and UTC alarm clock. (iPhone/iPad app by Dave Massey.) - Source: https://appshunter.io/ios/app/utc-orbit/id1049069115 (this page in markdown: same URL + `.md`) - Developer: [Dave Massey](https://appshunter.io/developer/1029584286) - Category: Utilities - Price: Free - Rating: 5.00/5 from 2 App Store ratings · 2 written reviews indexed - Age rating: 4+ - Requires: iOS 26.0 · 2 MB - Languages: English - Released: 2015-10-22 - Data updated: 2026-07-23 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/utc-orbit/id1049069115/reviews.md ## What is UTC Orbit? UTC Orbit; is a time conversion utility for use with Earth orbital elements calculations for spacecraft. The application also contains a UTC alarm clock that is based on "Day of Year". UTC stands for "Universal Time Coordinated", but is also known as Zulu Time or GMT Time. The application allows the user to select any epoch time in the future or past via pick wheels and that time is then displayed as YYDDD.FFFFFF where YY=Two digit year, where DDD=day of the year (000 - 366), and where .FFFFFF is the decimal fraction of the day. This is the standard format for manipulation of spacecraft tracking TLE's (Two Line Element sets). The app also works in reverse where the user types in the epoch time and the pick wheels will spin to the human readable date. The alarm is set via the pick wheels and operates in the background for sound and screen notification as well as the foreground if application is running. The user must "allow notifications" for the background to function. A useful feature of the app is that if you rotate the iPhone you then have a large digit UTC clock. iPad large digit clock is selected by touching the button "UTC screen". Note that this locks the screen rotation on all devices and to return to the calculation screen you must touch "Back to main screen". ## Key features - UTC time conversion - YYDDD.FFFFFF format display - UTC alarm clock - Day of Year alarm setting - Large digit UTC clock display - Background alarm notifications ## Recent user reviews (2 of 2) All indexed reviews: https://appshunter.io/ios/app/utc-orbit/id1049069115/reviews.md ### 5/5 — Excellent UTC and Day of Year Clock *2017-09-13* Excellent and straight to the point! ### 4/5 — Does what it says on the tin. *2015-11-27* Nicely-written software with a decent interface. This App does one thing, and it does it well. I like this uncluttered and simple approach Thank-you. If the screen-locking which is mentioned in the description could be removed, then I could rate the App with 5 stars. At the moment, the first window opens with orientation such that the charger connector is at the bottom of the screen - no good at all when charging an iPad. Worse still, when the full-screen clock opens, it is displayed in landscape, which is fine, except that it is inverted. My iPad stand places the charge connector and Home button on the left, which is fine for me; I'm left-handed. But a locked, inverted display is hopeless! At least, if the display must be locked, can we have a choice of orientation, please? Thank-you. I'll still be using this App, and awaiting the next version. :-) ## Frequently asked questions about UTC Orbit ### What is UTC Orbit used for? UTC Orbit is a time conversion utility primarily for Earth orbital elements calculations for spacecraft. It also includes a UTC alarm clock and a large digit UTC display. ### How does the YYDDD.FFFFFF format work in UTC Orbit? This format displays time as YYDDD.FFFFFF, where YY is the two-digit year, DDD is the day of the year (000-366), and .FFFFFF is the decimal fraction of the day. This is standard for manipulating spacecraft tracking TLEs. ### Can UTC Orbit be used as a regular alarm clock? Yes, UTC Orbit features a UTC alarm clock based on the 'Day of Year'. You can set alarms using the pick wheels, and they will function in the background with sound and screen notifications if notifications are allowed. ### Does UTC Orbit have ads? No, UTC Orbit does not contain advertisements. ### What devices does UTC Orbit support? UTC Orbit is available for iPhone, iPad, and iPod. ### How often is UTC Orbit updated? The latest version, 2.2, was released on December 29, 2020. The app was initially released on October 22, 2015. ### What is the age rating for UTC Orbit? UTC Orbit has an age rating of 4+. ### How do I switch between the calculation screen and the large digit clock in UTC Orbit? On iPhone, rotating the device activates the large digit UTC clock. On iPad, touch 'UTC screen' to activate it. To return to the calculation screen, touch 'Back to main screen'. ## Version history (last 5 releases) ### 2.3 — 2026-07-07 Updated to iOS 26 ### 2.2 — 2020-12-29 Updated to latest iOS. Brighter smoother user interface. Minor bugs fixed. ### 2.1 — 2020-04-29 Updated to latest iOS, App store requirements, and a few minor bug fixes ### 2.0 — 2019-11-07 Updated to IOS13 and dark mode contrast. Several bug fixes. ### 1.1 — 2016-01-15 Added new alert messages for alarm settings Fixed leading zeros on the day of year display ## Apps similar to UTC Orbit | App | Rating | Price | Category | | --- | --- | --- | --- | | [World Alarms](https://appshunter.io/ios/app/world-alarms/id991590327) | 4.2 (5) | Free | Utilities | | [Zulu Time](https://appshunter.io/ios/app/zulu-time/id377289826) | 4.9 (2,491) | $0.99 | Utilities | | [Moments₂: Count Your Blessings](https://appshunter.io/ios/app/moments-count-your-blessings/id1598683225) | 5.0 (5) | Free | Utilities | | [MultiClock Civil/Solar/Metric](https://appshunter.io/ios/app/multiclock-civilsolarmetric/id6468424886) | 4.0 (3) | Free | Utilities | | [EarthClock Time Zone Converter](https://appshunter.io/ios/app/earthclock-time-zone-converter/id6503596287) | 4.3 (6) | Free | Utilities | | [Pilot Time](https://appshunter.io/ios/app/pilot-time/id360138989) | 4.5 (19) | Free | Utilities | ## More apps by Dave Massey - [Solar Flux NOAA](https://appshunter.io/ios/app/solar-flux-noaa/id1029584287) - [Antenna GT](https://appshunter.io/ios/app/antenna-gt/id1055532103) - [IoT-Loader](https://appshunter.io/ios/app/iot-loader/id1145485602) - [IoT-Alert](https://appshunter.io/ios/app/iot-alert/id1145525984) - [IoT-Pass](https://appshunter.io/ios/app/iot-pass/id1145534244) All apps by Dave Massey: https://appshunter.io/developer/1029584286 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-23.*