Landscape photographers are often told “don’t pack up when the sun sets – wait!”

That’s sound advice – the best light often comes after sunset (or before sunrise).

Watching a spectacular sunset last week, I wondered how long after sunset the color in the sky would remain. Using TPE’s elevation above the horizon tools, plus a bit of Excel, I came up with some figures that estimate how long you can expect clouds to retain those spectacular sunset colors.

We put the information into an infographic. There’s even a “science bit” at the end :)

Cloud infographic

Infographic by Alison Craig

References and Links

Strange Clouds – NASA Science News
Dip of the Horizon by Andrew T. Young
Yallop, B.D., and C.Y. Hohenkerk. 1992. Astronomical Phenomena in Explanatory Supplement to the Astronomical Almanac, rev. edition, ed. P. Kenneth Seidelmann. Mill Valley, CA: University Science Books, Equation 9.31-1
Cloud Heights at Different Latitudes – Windows to the Universe

If you’ve enjoyed this post, you might also enjoy “Understanding Light with The Photographer’s Ephemeris” co-authored with renowned landscape photographer Bruce Percy. It’s available through Bruce’s web-site.


Tutorial Part 4 Step 3

We use a variety of different locations in our series of step-by-step tutorials for TPE for Desktop. At the time the tutorials were written, there was no easy way to import or export saved locations from the app.

However, since the release of TPE for Desktop 1.1.1, location import/export has been possible, using KML (Keyhole Markup Language).

As a convenience, I’ve collected together all the locations used or mentioned in the tutorials as a KML file that you can import into your own copy of TPE. There are 12 locations in total, labelled by tutorial part number, available here:

File size 4.52kB | Last modified Mon Oct 22, 2012 at 15:56 | Download count 985

To import locations into TPE for Desktop, just choose Locations, then click Import:

Location import instructions

You can also open this file in TPE for iOS and import them onto your iPhone, iPad or iPod Touch – just click on the download link, then choose Open in TPE from the Action menu. (We’re working on KML import for Android too.)

If you haven’t worked through the tutorials, they give a good grounding in how to get the most out of TPE. If you’d like to know more than just sunrise/sunset, they’re worth checking out:


Totem Pole formation - Monument Valley

Early Civil Twilight at Monument Valley

I had a request to our support email recently, asking if we could explain in layman’s terms what the different twilight times meant. In the past, we’ve also received requests to include times of “Blue Hour” or “Golden Hour” in TPE. The problem with those terms is that they have no strict definition, so we’d need to adopt our own definition in order to calculate times.

Better instead to use Civil, Nautical and Astronomical twilight, which are well defined terms. In the help file for TPE on iOS/Android, twilight times are described as follows:

Twilight times

Times of civil, nautical and astronomical twilight are shown. The different twilight times are defined as follows:

  • Civil: when the sun lies 0° – 6° below the horizon
  • Nautical: when the sun lies 6° – 12° below the horizon
  • Astronomical: when the sun lies 12° – 18° below the horizon

Note: not all twilight phases occur in all locations/times – for example, the sun may never set far enough for there to be an astronomical twilight phase at northern latitudes in summer.

Accurate, but possibly insufficient to understand how you would leverage this information in your photography.

TPE for Desktop includes a glossary of terms, which describes each twilight phase as follows:

Civil twilight:

Civil twilight is defined as the period when the sun lies between 6 and 0 degrees below the horizon.
Of the celestial bodies, only the brightest stars and planets remain visible during civil twilight. Illumination is bright enough to distinguish objects in the landscape.

Nautical twilight:

Nautical twilight is defined as the period when the sun lies between 12 and 6 degrees below the horizon.
At this time, stars remain visible in the sky for navigational purposes and objects on the horizon are only just visible.

Astronomical twilight:

Astronomical twilight is defined as the period when the sun lies between 18 and 12 degrees below the horizon. At this time, point light sources such as stars remain visible in the sky, but fainter objects such as nebulae and galaxies are no longer visible. The majority of observers would consider astronomical twilight to be effectively dark.

This gives a few more hints, but for the purposes of most landscape photographers, I think we can sum things up even better.

When to be there

In general, be there for the start of civil twilight. (Or until the end of – you get the idea…)

The start of civil twilight is when you will start to see some real colour in the sky, with a mix of the deep blues and intense oranges as in the photo from Monument Valley, shown above.

As civil twilight progresses towards sunrise, depending on cloud coverage and height, you may see spectacular pinks and reds develop.

What about Nautical and Astronomical Twilight?

For most photographers, these are less relevant. In general, you’ll need to be using far longer exposure times during nautical and astronomical twilight.

Often as not, landscape shots taken during these times will include one or more night sky objects, such as the moon or planets during nautical twilight, or stars (but not deep space galaxies – see above) during astronomical twilight.

Remember also, that you can make silhouette images during nautical twilight: the sky is bright enough to see the outline of landforms on the horizon, but not (with the naked eye) to make out detail in the landscape.

Enjoy your twilight shooting!

If you’ve enjoyed this post, you might also enjoy “Understanding Light with The Photographer’s Ephemeris” co-authored with renowned landscape photographer Bruce Percy. It’s available through Bruce’s web-site.

This article was published a while ago, but I stumbled across it again just this evening.

I thought it worth sharing as it combines two particular interests of mine: photography and marine biology.

Any of you who have tried scuba diving (or sailing or similar) may have experienced bioluminescence – the astonishing light emitted by plankton and other sea creatures under certain conditions at night.

Photographer Jerry Dodrill captured some amazing images of the setting moon, sea stacks and bioluminescence on the California coast last year.

You can read more over at Visionary Wild


When TPE for iOS was first released in April 2010, we had to put a dedicated website together for the app.

It’s one of those things that is easily overlooked (at least the first time around): you spend weeks and months polishing the app, and the excitement of being ready to release rather overwhelms any interest in standing up a new site.

So, when I realised that the pre-declared release date (the date I told Apple I wanted the app released) was almost at hand, I had to move quickly to put something together. The rather plain old site, thrown together over a day-and-a-half, has survived until now, largely unchanged, primarily because it was written in Drupal 6, which for me at least, has proved to be over-complicated and messy to manage.

So, I’m very happy to report that we’re now back on my favourite CMS, Textpattern. Textpattern isn’t the best known CMS out there – far from it – but I’ve found it to be fabulously flexible and elegant. I’d highly recommend it.

With the new site, we’ve ported over all the TPE-related articles and tutorials from my old personal site (stephentrainor.com) so the full history of the app can be hosted in one place. In addition, all the content from the previous site is here, mostly in the same place as before (so old links will be preserved for the most part).

We hope you like the new site and we’re looking forward to sharing additional TPE-related content and stories here, now we have a proper home for it!

If you have any feedback on the new site or spot any problems (there are bound to be some…), please drop us a line, or ping us on FB/Twitter.

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