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The September full moon – traditionally known as the Harvest Moon – has long been one of the more popular full moons of the year, it seems.

This year’s promises to be a spectacular one: not only is it the largest full moon of 2015 (i.e. a “supermoon” in modern media/astrological parlance), but it is accompanied by a total lunar eclipse (or a “blood” moon, according to the more excitable elements of the press).

We’ll be publishing more over the coming days on how and where to shoot this event, but to get the ball rolling, we’ve just added new events to TPE for iOS detailing the key timings and phases of the event.

Just tap the date at the top of the screen in TPE for iOS to see the newly added events for partial eclipse start and end, totality start and end.

Choose an event to read more details and then tap Select to go the precise date and time. You can then immediately see where the moon will be in your location to help plan your shoot.

"Blood Supermoon" details in TPE for iOS

Note: this event will occur on the evening of Sep 27 for those in the Americas, and in the early hours of Sep 28 for Europe/Africa. TPE will always use the time zone applicable for the location of the red pin, so you don’t need to do the time calculations yourself.

Watch this space for more information on the supermoon in the coming days!

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We’re pleased to announce that the Skyfire team rolled out some major updates to the forecasting algorithm this week.

If you don’t know about Skyfire, it’s a sunrise/sunset color prediction service for photographers, currently with coverage of the lower 48 states of the USA. You can read more here and reviews here and here.

Skyfire now includes three distinct weather forecasting models as inputs to its algorithm, with the latest addition being a higher resolution model that has excellent cloud resolution and handles storms and severe weather particularly well.

Skyfire screenshot - landscape

Changes released this week include:

  • An additional forecast run for sunset in the mid-afternoon
  • Haze analysis to allow better analysis of pre-sunset lighting conditions especially along the coast
  • Added an additional NOAA data source to the ensemble forecast which utilizes the newest weather models available
  • Multi-level cloud analysis will provide greater accuracy in some of the more complex weather cases, and take into consideration when multiple cloud levels are visible
  • Better handling of seasonal shifts

Skyfire is offered as an in-app subscription in TPE for iOS. There’s a free 30 day trial available, so give it a go and see if it can help you capture the best possible light!

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The 3.3 update for TPE for iOS was released today, with a few changes.

Updated World Magnetic Model

We updated the in-built World Magnetic Model for 2015 – 2020. Every five years, the National Geophysical Data Centre here in Boulder, Colorado and the British Geological Survey in Edinburgh, produce an updated model for how local magnetic north varies from true north.

If you enable magnetic north within the app (in Settings), then all azimuths and bearings are relative to local magnetic north. But not only that: magnetic declination varies over time too (which is why new models are required every few years). The model accounts for changes over time during the validity period (now 2015 – 2020), so TPE uses the magnetic declination for both location and date to give the most accurate result.

We’ve open sourced our iOS wrapper for the World Magnetic Model: it’s available here if you need it for your app: https://github.com/stephent/ObjectiveWMM

Visual Search is up to 80% faster

Apple has made great strides in providing improved performance measurement tools for developers. We’ve been using those tools to optimise some of the astronomical calculation code underlying TPE.

Visual Search is calculation intensive: multiple sun and moon position calculations are required, even with interpolation between results. As a result, any improvement in one of the basic calculations reaps big rewards for Visual Search.

In 3.3, Visual Search is up to 80% faster.


TPE + Skyfire running on iPhone 6 Plus

We’re delighted to have partnered with Skyfire to bring their sunrise and sunset color forecasting service exclusively to TPE.

Skyfire covers the lower 48 states of the USA at present, with expanded coverage planned in the future. It’s available as an in-app subscription with a 30-day free trial.

We’ll be adding Skyfire to other versions of TPE over the coming months.

Read more

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TPE 3.2 for iOS screenshots

We’re pleased to announce the release today of TPE 3.2 for iOS.

The new update includes a number of improvements and some exciting additional features.


  • Map buttons can be hidden on iPhone to increase usable map area
  • New setting to control whether to use Satellite or Hybrid maps (you may prefer Satellite if the map labels obsure your shooting location)
  • Locations can now be marked as favorites
  • Your favorite locations are shown on the map by default (you can disable this via settings)

These changes are designed to improve the utility of the app.

Map buttons

For users on smaller screened devices (3.5” and 4”, i.e. iPhone 4S and iPhone 5), the ability to hide the map controls will provide a useful increase in usable map area for those times when you need to focus your attention on geographic matters.

Satellite maps

In a similar vein, the option to use plain satellite maps, instead of hybrid maps where map labels may obscure landscape features, means you now have a mechanism to clear the way and focus in on the satellite imagery. This option is available for both Apple and Google maps: you may find that one provider has better satellite imagery than another in certain locations – if you don’t like what you see, it’s worth switching over to see the alternative. Go to the TPE Settings page to change map provider.


Firstly, we overhauled the locations screen to use Apple’s latest SearchController API, which provides better stability and performance and is much simpler under the hood.

Secondly, we added the ability to mark any location as a ‘favourite’. A few users have asked for the option to display saved locations on the map at all times. However, the downside with that approach is that you can end up with hundreds of map markers as your location list grows.

Using favourites offers a middle ground that lets you decide which locations are most important to you, and mark them as favourites. All favourite locations are permanently displayed as a star icon on the map. You can tap on the favourite location marker on the map and then select the button in the popup info window to set the red pin directly to that location. And, if geodetics is enabled, you’ll be prompted to choose whether to move the red or grey pin.

Additional features

Location synch is here for iOS

We’ve added an option to let you synchronise your saved locations between TPE for iOS and the TPE Desktop Web App.

We know many of you like to plan your shoots at home on desktop or iPad, and then have the relevant information at hand when you’re on the road.

Location Synch makes it easier than ever to do just that. Rather than manually importing, exporting and managing locations via KML, you can synchronise at the touch of a button between all your devices running TPE for iOS and any instances of the TPE Desktop Web App.

To use this feature you sign up for a free Crookneck Photo Apps account. What’s Crookneck? That’s us, the makers of TPE. Why an account? When we store your saved locations during synchronization, we need a way of associating that location to you, its creator. A user account is the easiest way of establishing that association.

Location Synch is offered with a free 90-day trial. Thereafter 12-month subscriptions to this feature will cost $0.99 (in the US).

Why isn’t it free?

We decided against using solutions like iCloud (Apple only) and Dropbox (they actually deprecated their per-record synch API earlier this year) in order to ensure we could offer this feature across all our supported platforms. (That’s right: we expect to bring it to Android later this year.)

In building and operating our own platform there are ongoing monthly costs to keep it running, in addition to the development and maintenance efforts. These costs include application hosting, cloud database instances, monitoring services, SSL certificate costs etc.

We want this to be a sustainable feature, so we’re asking a modest subscription fee to ensure that these costs are covered. For the cost of 1/3 of a single cup of coffee you get a yearly subscription to synch your TPE locations across all your iOS devices and TPE web app versions.

A few other changes

  • The Synch button has been added to on the locations page; the edit button has been removed. To edit, first choose a location in the list. When selected, the edit button is displayed on the right (the one with the pencil). To delete a location, go back to the locations list and simply swipe a location to the left and choose Delete (just as you would with the iOS Mail app)
  • The button to send the grey pin to a saved location now only appears if geodetics is already enabled. To enable geodetics go back to the map, choose the grey geodetics button on the right of the map. Back in the locations screen the grey pin is now displayed as a button in the location cell
  • Amongst various bug fixes, one notable fix is that it is now much harder to lose the grey pin, which did have a habit of zooming off screen when positioned from a saved location
  • We have updated to the latest Google Maps SDK. Most importantly this means that terrain maps zoom in much further. Yay!

We hope you enjoy the new updates. We have at least two more major updates coming this summer with more new features, so look out for those!

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Total Lunar Eclipse, April 15 2014

Saturday’s total lunar eclipse is expected to last a mere five minutes, making it the shortest of the century. If you want to capture a memorable photograph of the eclipsed full moon, some planning is going to help.

While Europe will miss out on this eclipse, the timing works out well for western parts of the Americas and Asia.

The eclipse occurs at moonset in the Americas, and as it’s a full moon, moonset occurs early in the morning. Let’s look at a couple of examples from opposite sides of the world:

Boulder, Colorado

Total eclipse will happen at 6:01am on the morning of Saturday, April 4, 2015. The moon will be setting to the west during late nautical twilight, meaning the sky should be a perfect complementary deep blue to the striking deep orange of the eclipsed moon.

Boulder looks up to the foothills of the Rockies to the west of town. If we can be sure that the moon is high enough in the sky, we should be able to capture it hanging above the famous Boulder Flatirons, a group of sandstone formations that sit above the south part of town.

Using The Photographer’s Ephemeris app on iPad, we can see that indeed, the moon will still be high enough in the sky to be visible above the Flatirons. In fact, it will be sitting above a gap just to the south of the main Flatirons group, if we shoot from the trail near South Boulder Road, which offers some decent foreground opportunities as well as relatively unobstructed views westwards:

TPE Screenshot

This is roughly where I plan to be this coming Saturday – hopefully, the weather will cooperate and there’ll be some decent shots there for the taking!


In contrast to America, Singapore and other parts of Asia will see the total eclipse around moonrise. In Singapore, maximum eclipse occurs again during nautical twilight, with the moon rising to the east.

Singapore is a wonderful location for architectural photography. Since I was last there ten years ago, a number of striking new buildings have been constructed. One of the most prominent is the Marina Bay Sands.

Marina Bay Sands in the evening
Marina Bay Sands in the evening – 20101120“ by SomeformofhumanOwn work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

Might it be possible to shoot the eclipsed moon juxtaposed with this building?

It appears that the answer is yes – and even better, it looks like it should be possible to catch the moon in a gap between the towers. From Wikipedia we can find the building’s height of 200 metres (656ft). We can use the geodetics feature of The Photographer’s Ephemeris app on iPad to visualize the height of the moon in the sky relative to the building height.

If the moon lies below the top of the building when viewed from a suitable distance, and if we align ourselves with the gap between the towers, then we should be able to shoot the moon through the gap. The screenshot below shows a possible shooting location on the west shore of the bay (the map is rotated to view more or less due south), facing eastwards to align the rising moon with the Marina Bay Sands building:

TPE Screenshot

As you can see, the moon does indeed lie below the top of the building at the moment of maximum eclipse (8:01pm local time): the chart beneath the map shows the relative altitude of the building (the solid white line on the right hand side) and the moon (blue line). Using the tilt feature of Google Maps, it’s possible to check that we are aligned with the leftmost gap between the towers.

A 5-minute window of opportunity

Although it’s short, the April 2015 lunar eclipse is a gift for photographers: with the moon visible low in the sky at either moonrise or moonset during twilight, there are a huge number of possibilities for attractive compositions that place the moon next to a landmark, building or natural feature.

There’s still time to plan your shot, so don’t delay!

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