UTC Orbit vs Julian

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".

Julian makes it simple to find any day of the year, convert dates, and understand your year at a glance on iPhone, iPad, and Apple Watch. Browse the calendar to explore past and future dates, or enter a day number to jump straight to the matching date. Choose the date format you prefer and instantly see the day of the year, year progress, days remaining, week number, and current quarter. Convert between calendar dates, ordinal dates, ISO 8601 dates, ISO week dates, Julian calendar dates, Julian Day Numbers, and Unix timestamps. Add or subtract days, weeks, months, or years, or calculate the exact time between two dates. Julian supports a wide range of astronomical and time counting systems, including CCSDS Julian Date, CNES Julian Date, Dublin Julian Date, Lilian Date, Mars Sol Date, Modified Julian Date, Rata Die, Reduced Julian Date, Truncated Julian Date, and Unix Time. Copy any date value with a tap, or copy and share a complete date summary. Save your favorite formats for fast access whenever you need them. Keep important date information visible with Home Screen and Lock Screen widgets. Customize their layout, colors, and content. Larger widgets can show additional date values and calendar views without opening the app. On Apple Watch, quickly view yesterday, today, and tomorrow, look up any day of the year, and choose complications that match your watch face. Use Siri to retrieve date values and check your year progress. Add Julian actions to Shortcuts to convert dates, perform calculations, copy results, and open detailed date information. Personalize Julian with seven color themes, alternate app icons, and System, Light, or Dark appearance. Set your preferred first day of the week and choose which month begins your first quarter. For an instant glance, enable the optional app icon badge to show the current day of the year. Badge updates are silent and do not create banners or sounds. Notification permission is required.