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The video below was featured on Adorama TV a while back. A big thank you to Mark Wallace for the thorough review of TPE on iPad!

This week Mark Wallace discovered a great iPad application that is called The Photographer’s Ephemeris.

AdoramaTV presents The Photographer’s Ephemeris for iPad. This app is helps you plan outdoor photography shoots, particularly landscape and urban scenes. It is a map centric sun and moon calculator. Some features including visual sun and moon searches, automatic time zone and elevation detection, correction for atmospheric refraction and height above the horizon, ensuring that you have the best possible information for planning your shoot.

For related articles and videos, and to download The Photographer’s Ephemeris, go here: http://www.adorama.com/alc/article/The-Photographers-Ephemeris-AdoramaTV

Buy an iPad at Adorama.com

Visit http://www.adorama.com/alc/ for more photography videos.

Send your questions to: AskMark@Adorama.com


Brief update to say that The Photographer’s Ephemeris is now officially out of Beta!

The new version is available for download now and current users will be prompted to auto-update.

The desktop version of TPE remains free of charge and the program will not expire.


I’ve updated TPE today to version 1.0 RC1 – it’s close to done (for version 1 at least).

A couple of features of note:


I’ve been using the SRTM (Shuttle Radar Topography Mission) data set via the Geonames web service. This is a fairly mature data model and the quality is high. However, it has a couple of limitations for our purposes.

Firstly, the latitudes of the model extend only to 60° north and 56° south – not far enough for some of the locations that photographers get to nowadays.

Secondly, many mountainous peaks and slopes would return “No Data” due to measurement difficulties when the angle of incidence of the radar was too high. Again, many landscape photographers are interested in precisely these locations.

In this version we’re adding two other elevation data models to the mix: ASTER GDEM and GTOPO30.

ASTER GDEM was released only earlier this summer, but Geonames already has a web service supporting it. The coverage is much wider (83° north and 60° south) and mountainous areas are better covered.

However, there are apparently still some holes and data anomolies in the model (see the reference in the Wikipedia article linked above).

GTOPO30 is another model with even wider coverage but with lower resolution and the data is older than the other two sources.

So, in the new version of TPE, I query SRTM first and then ASTER and finally GTOPO30 if either preceding service returns “no data” (or the location is out of range).

Twilight azimuths

I had a request from Tim Parkin to display the azimuth lines for the sun both before sunrise and after sunset. This is useful if you’re looking to track the twilight glow on the horizon.

So, the program now shows this (in the Details View) up until the end (or from the start) of Astronomical Twilight.


A very quick post to say that TPE 0.9.5 is available. Here’s the updated feature list:

Beta 0.9.5

  • Improved Details view now includes Twilight times and Geodetics panel
  • Use secondary map marker to determine when sun or moon will clear an obstacle such as a mountain (Geodetics)
  • Correct rise and set times for the dip of the horizon (e.g. the sun is seen to rise earlier from a mountain top)
  • Use secondary map marker to set elevation at the horizon, or specify manually (to calculate dip of the horizon)
  • View the estimated distance to the horizon on the map, based on height above the horizon
  • Swap primary and secondary map marker positions using button or keyboard shortcut (S)
  • Haversine formula (for determining great circle distances) replaced with Vincenty algorithm for improved accuracy
  • Ctrl + and Ctrl – zooms in and out of map
  • Number keypad plus and minus added to keyboard shortcuts
  • Revised and expanded glossary
  • F1 key opens usage instructions in browser (requires internet connection)
  • Fixes bug where rise/set times were not recalculated on double-clicking map
  • Fixes bug where previous/next event in details view could stall on a particular event
  • Tooltips updated and corrected

Quite a lot in there. I’ve added some notes on how some of the newer advanced features work here.

I need to write up some proper tutorials on many of these with examples of actual shoots – keep an eye out, I’ll try to add a series of posts starting soon.

In the meantime, enjoy, and let me know of any problems you find.

[Originally posted on stephentrainor.com on 28 Jul 2009 · 00:23:59]


The Photographer’s Ephemeris v0.9.0 is now available.

Fairly minor changes, but useful ones:

  • You can finally resize the window: those of you with large monitors can now make the most of them to really dig into the details of the map area. Thanks for your patience on this one. So long you don’t go larger than 1200px high, you’ll reveal a selection of additional eclectic graphics down the right hand side, courtesy of my wife, Alice.
  • If you’re in the Details view and you change the date, the program doesn’t revert back to the multi-day view as it previously did. You can now scroll from day to day and see how the timing of the moon shifts by watching the details graph.
  • Finally some minor changes to the About page, including proper credit for the moonrise/set algorithm that is used (thanks to Jeff Conrad for the pointer on this)

I had hoped to have a couple of other features incorporated into this version: (i) correction for height above the local horizon and (ii) altitude (i.e. angle in the astronomical sense) of obstructions above the horizon, such as the mountain between you and the glorious sunset.

While all the maths is working (for the first of these at least), getting the UI right is proving tricky. One of the nice things about the current program is that it requires only two user inputs: a place and a date.

Once you introduce corrections for height above horizon and alitude of objects on the map, the number of inputs, and therefore the complexity for the user immediately increases.

So, I try to ask myself (not, in all honesty, having much of a clue as to the answer): what would Steve do? Haven’t worked it out yet.

As ever, your comments and feedback much appreciated.

Some recent quotations

To end, a handful of recent quotations about TPE:

My all-time favourite(!) from Steev Selby

This is the holy grail of sunrise/set programs

From Wasabi Photo

I am frankly gobsmacked by what this nifty software can do … it is rare that I am in awe by what you can find on the internet for free .. but this is one of those times when I am really blown away.

From Alex Wise down in one of my favourite places, Australia

I’ve seen similar things done in the past but find this much better and think its a must for any landscape photographer.

On EOS-Network

Just occasionally, you find something really useful. If you only found this blog today, then today is your lucky day because this’ll be the second really useful thing you’ve found!

Hola! Witaj! Szervusz!

Finally, hello to visitors from Spain, Poland, Hungary. Looks like TPE has been picked up via a number of sites over in Europe and indeed the majority of traffic over the past few days has been coming from those parts of the world.

I appreciate your linguistic abilities and forbearance with my anglophone application :-)

[Originally posted on stephentrainor.com on 17 Jun 2009 · 23:00:59]

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