High Dynamic Range – Into Visual Fantasy

I like to say that what we see depends on how we look. No matter how much we may think that a photograph is a “real image” and what you see is “just they way it looked,” photographs are always interpretations, full of assumptions, conventions, and the ever-present interplay among art, technique, and technology. This is particularly true in astrophotography.

Even the stunning images taken by telescopes such as the Hubble Space Telescope are actually highly artificial. Not only do they represent magnifications far beyond what our own eyes can achieve, they also are made possible by gathering light from fantastically feint objects. Furthermore, they usually represent an artificial spectrum, a selection of colours represented on the image that are not the “natural” appearance of an object at all. Astrophotographers, artists, and anyone else working with these images can select various wavelengths of light that were captured by the original camera and transpose them into what we see in the final image.

That’s all by way of introduction to the following image, which I made on the evening of 14 June 2013. It’s a High Dynamic Range rendering of the moon, generated from three different photos taken in succession but at very different exposures. One exposure was short enough to capture details in the sunlit areas to the right; one was long enough to capture “earthshine” on the left. Merged together in the computer, they make a stunning image – not what you see of the moon at night with your eyes, but the moon none the less. In this rendering, I have exaggerated colours for effect:

Moon in HDR

Two faces of the moon. A High Dynamic Range image made by combining three photos taken on 14 June 2014 at different exposures. The sunlit side, on the right, is many times brighter than the earth-lit side on the left. Photographed with a Nikon D800 body on a Meade 125TB Maksutov Cassegrain telescope, on an EQ4 motorized mount. The earthlit side was exposed at ISO 800 for 10 seconds. The sunlit side consisted of two shots at 1/3 and 1/30 second. The three images were combined with Dynamic-Photo HDR.

High dynamic range imaging does not have to result in “garish” images, however. The original intent of the method was to make more detail in shadow and in highlight visible. Here’s another rendering from the same evening that is a little more “realistic” but was prepared, essentially, the same way:


The moon on the evening of 14 June 2013 – with both bright side and earthlit side represented in an HDR image.

Copyright © 2013 David Allan Galbraith

Happy Golden Anniversary Valentina Tereshkova

It is truly sad, but there are some people out there – perhaps more than I’d like to believe, who apply labels to others in an attempt to keep them from achieving their dreams. We all win when someone breaks the mould and flies high. Today, 16 June 2013, is the 50th anniversary of Soviet cosmonaut Valentina Tereshkova piloting Vostok 6 into space. On 16 June 1963, she became the first women in space, and not as a passenger, either – but as a fully trained, capable space-farer.

According to the Wikipedia entry for General-Major Tereskova (http://en.wikipedia.org/wiki/Valentina_Tereshkova), who was know by her airforce handle “Sea Gull,” she has another very interesting distinction (among many). After her two day 1963 space flight she married Cosmonaut Andrian Nikolayev, who flew twice in space himself. Their daughter, Dr. Elena Andriyanovna, is the only person to have parents who were both space travellers (at least so far).

Since General-Major Tereshkova’s ground-breaking (or should I write “space-breaking” instead) flight 50 years ago, a total of 56 women have flown in space. The largest number of these have been aboard the US Space Shuttle, and Canada is very proud to have had two women astronauts to date, too (Dr. Roberta Bondar and Julie Payette).

These path-finding women prove that categories such as male and female do not limit or define what we can do as humans. At least, they should not. Unfortunately for many people, these categories and others such as ethnicity, spiritual or religious tradition, nationality, sexual orientation, or physical or mental abilities, are used as labels to define – and curtail – the aspirations of others. That kind of limited thinking is a form of bullying that our world cannot afford any longer. Let’s hope that the legacy of “Sea Gull” and all space pioneers is a world where our frontiers as individuals and as a species are not limited by anything other than the sizes of our hearts as we rise to meet challenges and fulfil our own potentials.

Copyright © 2013 David Allan Galbraith