Ephemeris of the Moon, Sun and Solar System Planets plus more...

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IMPORTANT ACCESS INFORMATION: TideLock only requires permissions to access an Internet connection plus vibration for your timer. The purpose of this permission is to retrieve the weather information from the National Oceanic and Atmospheric Administration or from the WeatherAPI, if the former one fails. There is absolutely no other purpose to this, for your peace of mind.   Update: To enhance the user experience we have added GPS GeoCoordinate Acquisition (optional) to TideLock. If you choose to use this function, location services permissions are required as well.

IMPORTANT SUPPORT INFORMATION: TideLock appeals to the broadest category of devices but on some devices, screens may be too small to display all data required. TideLock is recommended on Android 5 or higher and Windows 10 or Linux.

Application Description

TideLock is an expanded version of Regolith and the MoonLock applications also by Madvox. TideLock provides accurate ephemeris for the Sun, Moon and Planets as well as a number of additional useful resources such as orbital visualizations, timers, calculator, moon calendar, moon visibility, moon phase, rising and setting times etc.

TideLock has two purposes: On one hand, it is a useful tool for casual observers or the general public if you need to know what the current phase of the moon is or where the moon or planets are located. On the other hand, it is an observer aid if you are next to your telescope as it allows you to do the things mentioned above plus a number of other useful activities such as timing events, looking at proper time formats, display an HD map of the moon which can be zoomed into so that you can more easily locate features, etc.

TideLock v2.0 is a redesign of the original program. There is a road-map for TideLock which includes upcoming features such as visualization of the moon in the horizon, star charts, timed events, asteroid tracking, imaging, and perhaps in time, Telescopic Interfaces.

  • Main: Application Entry Menu

  • Moon: Main Moon Functions

  • Moon: Monthly Moon Calendar

  • Saturn: Saturn Orbital Simulation

  • Compass: Compass Functions

  • NOAA Weather: NOAA Weather Data

Application Features


  • Full Lunar Ephemeris
  • Solar System Ephemeris
  • Orbital Visualizations and Simulations
  • Scientific Accuracy
  • Detailed Ephemeris


  • Moon Phase & Calendar
  • Rise and Set Times
  • Galilean Moons
  • Saturn's Ring Positions
  • Much, much more...


  • Perpetual Calendar
  • Calculator and Timing Tools
  • Fully Personalizable
  • Coordinate Based - Worldwide
  • Not invasive - total privacy

Hints and Tips and Comments

TideLock Instructional Video


Frequently Asked Questions

I started the app, went to moon phase and see nothing: You need to enter your geographical coordinates before most functions will show any data or moon phase. TideLock is a highly accurate application. While we could default to show you data for some default location at some default coordinates at 00 hours GMT we want to show data relevant to you.

But what if I am traveling or move?: No problem, just enter or acquire new coordinates in the settings page any time you want. You may do this as many times as you wish to.

How does this app help the amateur observer?: TideLock can be used at the telescope to obtain relevant data for planetary objects and satellites. For instance, if you are observing and need to report your observations, TideLock can be used to obtain accurate UT Time, Central Meridian data, Sun and Moon colongitudes, colongitude of the terminator, magnification data, etc... You can calculate these yourself or carry a copy of the Astronomical Almanac or... you can have TideLock in your pocket and just press a button and get all this info.

How reliable are the orbital simulations of Jupiter's and Saturn's satellites: TideLock is designed to be real-time accurate so as you start the simulation for a given time, what TideLock shows you is what you should see at your telescope. Do note though that to make things easier to see, TideLock does not draw to scale so the satellites drawn by TideLock are much bigger than in real life. Nevertheless, transits, shadows, occultations and the GRS are accurately represented.

What is the GPS button for in Settings?: The GPS feature connects to the GPS services over the Internet to acquire your exact geographical coordinates and put them in the right fields for you. This is done for your convenience.

How accurate is the GPS acquisition?: TideLock does not use phone tower triangulation. TideLock contacts the GPS Satellite services directly for high accuracy. The resulting location is as good as Google Maps or equivalent GPS service.

The weather page is not showing my city: You need to set your coordinates. Use Google to find them (e.g. Washington DC Coordinates) and enter them as you see them. Additionally, NOAA weather is only displayed for US locations where WeatherAPI is valid worldwide. Choose the correct one under Settings, for your location.

I entered Google coordinates and the city is still wrong: Do not use minus sign for southern and western coordinates. Use cardinal point drop downs. Your choice of cardinal points insert a negative (or positive) sign into the calculations automatically

The information provided by this program does not always match NASA's or [enter-name-here]: For total spacecraft accuracy, I recommend you use NASA's data or data from other well-known astronomical site like USNO. This program is "sufficiently accurate" (Meeus definition) but it does not intend to replace those sources at all. Having said that, this program is very accurate.

How accurate is the program then?: It is very accurate and, using Meeus' own words - it is sufficiently accurate - so that when you look at the moon or other objects it will match what you see. The accuracy concerns need bother you only if you are intending to do professional detailed scientific observation work. To find the moon and its phases and mean distances and orbital parameters or, to observe Jupiter and obtain planetary ephemeris, this program is very accurate!

Some other programs report slightly different phases or times: This program takes into consideration your geographical location as well as your time zone and altitude and thus, it may provide more accurate - if slightly different results, than others that simply report mean data at 0 hours GMT. For almanacs, this program does default to midnight UTC. But again, this is "sufficiently accurate", just to dispell any concerns. Also, the almanac may display two equal or similar phases of the moon if they happen to fall between two days but again, that will be 99.9% accurate.

The illuminated fraction of the moon differs from the ephemeris page/phase page and the almanac page: this is normal because: the ephemeris and phase pages calculate the phase of the moon for your exact local time, latitude, longitude and altitude. The almanac and the calendar pages calculate the phase for UTC 0 hours which can be a different time or even the next day with regards to the time you have set. So this is normal. Simply know this: when landing on the Ephemeris page or on the Phase page directly from the main menu, the time is defaulted to your local time unless you change it on the Ephemeris page itself. If you access these pages from another page, the time is set by that other page (in the case of the calendar or almanac, this will be midnight UT). If you need help understanding this please watch our educational video here.

Are there detailed instructions on how to use this program? Yes, here.

Some times I see more than one [full moon] in a month: Yes, this can happen for two reasons... There is indeed a second moon because the moon cycle is shorter than a regular calendar month or... you are in the almanac page which provides fast approximations. When in the almanac page, consult the illuminated fraction (provided) of the disk which will clear up which phase is the actual one on that month.

What is the range of timing accuracy of this program?: Year 2000 to 2050 (2100 for Eclipse Data). I deliberately limited the calculations to that time frame because this program does not require data beyond the Y2K epoch and to speed up performance on small devices.

What other sites can I refer to for additional information?: In addition to the NASA LRO site provided above, you can visit one of the topmost authorities here at the US Naval Observatory.

Do the default coordinates visible in the Observatory page correspond to a real place?: Yes, they correspond to Huelva, Spain? Why? Because... :)


Roguetoad Studios - This program was produced with the help of Roguetoad Studios who provided images, themes and icons. Some Icons were also used from the Crystal Nuove repository for Linux under permission - those icons are licensed to their respective owners..

This program found inspiration and sometimes algorithm help from the following authors:

Paul Schlyter
A.P. Hayes

Build / Release Information

Released April 2017 as 2.0.8, Updated August 2017 as 2.4.4, Updated September 2017 as 2.5.0, 2.6.0, 2.7.0, 2.7.2, 2.7.5, 2.8.0