The Photographers Ephemeris (TPE) Versus PlanIt! for Photographers

Note: I have no affiliation with either program.

TPE is probably the best known ephemeris application used by photographers. There is, however, a new kid on the block, PlanIt! for photographers.

While TPE does a good job of being a basic ephemeris, it ends there.

Shortcomings or challenges with TPE

Like all good photographers, you’re planning a future shot of the moon rise. You consult TPE for the rise time at your selected location and, in due course, set off with plenty of time to prepare your gear. Comes the appointed time and the moon doesn’t show! TPE got the moon rise time over the horizon right, but didn’t note the hill in the way. TPE can, however, find the hill. It’s a fairly complex process that involves many steps and some calculation on your part, and the potential for getting it wrong is high.

How PlanIt! picks up the slack

PlanIt!, on the other hand, goes much further. Not only does it give you the rise and set times of moon, sun, Milky Way and many stars but it lets you know if there is an obstruction and when the desired celestial object will clear that obstruction. All you need to do is read the information off the screen.

Moon over Half Dome

There are three major menus in PlanIt!: Ephemeris Features, Tools, and Backgrounds. By combining the features of these menus there are more than 500 possible variations of the information available to you, the photographer. All the features in Planit! are location and time specific. You set them to your requirements.

With 12 separate Ephemeris Features, see below, PlanIt! pretty well has it all covered.

Ephemeris menu

With a few exceptions, the Ephemeris Features are self-explanatory.

Milky Way:

By zooming out on the map you will be able to use the Milky Way Center and Finder functions. In the Milky Way Center function you will see the times of visibility, the angle above the horizon and the bearing of the centre. If it is visible at the time and place entered, you will see an arc of red dots with a row of green dots representing the center of the Milky Way. The Finder function, on the other hand, will produce a list of times, between starting and ending dates, when the Milky Way will be visible at the selected location.

The screen shot below shows the Milky Way over the Half Dome. This screen shot is in Panorama mode with the background in Viewfinder (VR) and graphically shows the relative heights of the mountains in the background. The broken lines at the bottom of the picture tell you that with a focal length of 24mm, a resulting field of view of 40 degrees, and an overlap of five degrees you will need five shots, at the centres shown, to create this panorama.


Dark Sky:

This function uses the 1-9 Bortle Scale to indicate where you are most likely to get the best showing of stars. A one on the scale indicates a very dark sky, in other words no city lights and lots of stars, while nine means forget the star shots and photograph the brightly lit buildings instead.


Calculates the various parameters for a time-lapse film strip. You insert up to three of the four criteria, and PlanIt! calculates the rest. If you are doing star time-lapse, and the sun or moon will affect your plans, then PlanIt! will alert you to the fact and correct your timings.

Time lapse

The example above reads, from right to left, as: To make a 30 fps clip of 10 seconds duration, and you decide to take a shot every three seconds, it will take you 15 minutes in total and 300 photos will be taken.


Calculates the exposure triangle based on current light conditions as detected by your phone. Various Neutral Density filter values, and light measuring methods, are available via a drop-down menu.

Light and shadow:

Light and shadow gives you a graphical representation of where the light and the shadows will fall on a scene.

That covers the ephemeris part.

On my Samsung phone, pressing the bottom left key brings up, among other things, the Settings Menu. Scroll all the way down until you come to the Camera Settings. By entering your camera type, especially the sensor size, you enable the full strength of the scene planning features of PlanIt!.

These features are selected in the Tools Menu and, coupled with various ephemeris and background features, a whole new world of scene and equipment planning is yours.


Tools menu

Once again the menu items are mostly self-explanatory.


Allows you to enter a location by name or latitude – longitude. Provided you have internet coverage, and have enabled location services on your phone, PlanIt! will centre the map on your selection and, if necessary, automatically correct the time zone to the new location.


Calculates the distance between the camera and scene icons. If the view is obstructed the green sight line will include a red section indicating where the obstruction is located. This feature gives you the opportunity to reframe your shot before going on location. The screen shot below shows the camera (the blue pin) just west of Yosemite Creek. The scene pin (red one) is off-screen but still located at the Half Dome. The shot cannot be made from this location because the ridge marked Yosemite Point rises higher than the sight line, hence the red section.

Distance  obstructed  view

The scene pin shown here with an exclamation mark indicates that the actual pin is off-screen. The camera pin will also be shown this way if it is off screen. Both pins can be left floating (will always be shown on-screen) or can be locked to their selected positions on the map, as is the case above.

Focal Length:

Part of planning your shot is knowing what lens to use. Here is where PlanIt! really shines.

In the screenshot below, the green shaded area represents your Field of View for a given focal length. By altering the width of that view, PlanIt! immediately calculates the focal length necessary to achieve the shot. Conversely, altering the focal length will change the Field of View. So, by using PlanIt! you will always have the correct lens in your kit for any shot. Coupled with focal length, you can also see Depth of Field, and hyperfocal distance.

Focal Length Horizontal

Depth of Field:

The aperture setting is ignored in every setup except Depth of Field. Here you are able to alter the aperture setting, and read off the Depth of Field limits as you do so.


As the name suggests, it calculates the number of shots, the focal length, the Field of View, and the overlap required to produce a cohesive set of shots with which to create your panorama.


PlanIt! uses Google Maps as the basis for its various displays. This means the usual Google Map functions are available, plus a few others.

Backgrounds menu

The Map (Picture) background allows you to use a downloaded, or photographed map, e.g., a picture of a tourist map in a park. This requires correct orientation of the map to be of any real use.

The various Viewfinder backgrounds allow the scene to be depicted in a number of ways, each giving different details of the scene. The (Picture) option actually uses the phone viewfinder as the background. Obviously this requires you to be on location, and your phone to have compass and GPS capabilities.

It goes without saying, in such a comprehensive piece of software, that camera orientation, portrait or landscape, can be selected and this, in turn, affects the view presented. The change between horizontal and vertical focal length being a classic example.

Compare the almost bewildering array of possibilities in Planit! with the ephemeris features of TPE and I think there is a clear winner. Planit! for photographers is available for Android 4 and above in Google play store and has recently been ported to iOS. My thanks to David Qiao of Yingwen Technologies for the screenshots.


The post The Photographers Ephemeris (TPE) Versus PlanIt! for Photographers by John Sharples appeared first on Digital Photography School.

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