Q&A: Phillip Chee

For the past four years, Phillip Chee has been documenting what is perhaps the oldest and most mysterious object of human interest: the sky. Already a trained biologist and philosopher and a working computer scientist, Phillip has also become an accomplished self-taught astrophotographer, meaning he uses the tools of photography to capture such celestial objects as constellations, planets, galaxies, aurora, meteors, comets, nebulae and star clusters.

I’ve been watching Phillip’s body of work grow (and grow more gorgeous) for a couple of years now, and had the distinct pleasure of asking him about the science and art behind it recently.

You’re a self-described “Computer Science Geek.” What’s your day job? When did you also become an astrophotography geek, and how did it happen?

I’m a computer science technologist at Sir Sandford Fleming College in Peterborough, Ontario. I spend a great deal of my time with computers, networks, software installation and configurations, and I also teach web site design. I became an astrophotography geek through sheer serendipity. There were two moments that led to it, really. The first was a project organized in January 2006 by an online photography community I belong to called Utata. The theme of the project was night photography, and because I’d always had a passion for astronomy (I even considered becoming an astronomer when I was in high school!), I chose the astrophotography category for my project images. Then in early 2007, I took the plunge for good when I bought an intervalometer (a remote shutter release that can be programmed to take multiple timed photos) for my camera. But really, the “ah-ha!” moment came when I was dropping off my daughter at a Girl Guide meeting. Venus was prominent in the twilight sky in early 2007 and it seemed to beckon me to enter the realm of all things astrophotography.

Can you tell us about the basic setup you use and what a night’s work is like?

My astrophotography is mainly wide-field (meaning you don’t need a telescopic lens), because this is the easiest to start with. I use a Nikon D200 DSLR, a remote timer, a sturdy tripod and a variety of lenses, mainly my Nikkor 10.5mm fisheye. I also shoot on film, and my favourite camera for this is my Nikon F3HP, because it has a setting which allows you to trip the shutter and keep it open indefinitely without requiring you to hold down a shutter release cable. That way you can walk away and use your hands for other things.

Most of the photos I take have exposure times between 30 and 90 seconds long, but it may take over a hundred exposures to create a single image. Because celestial objects move across the sky, my camera has to move with them. I use a tracking platform that permits me to follow any object at the rate of the Earth’s rotational speed. It attaches to my tripod and then I mount the camera to it.

At the end of the night I may have spent two to three hours outdoors with my camera. With the long exposures and intervalometer I can just look up and admire the view, or if I get bored I go inside. Or I may have my iPod Touch and just groove to a great playlist.

Why do you need so many exposures to make an image?

With astrophotography, the key to getting a good image is basically collecting as many photons on the sensor as possible while minimizing noise from long exposures. To do this you have to take a number of images of the same object and stack them together. I stack them all together, then subtract what are called “dark frames.” A dark frame is basically a photo with the lens cap on, taken using the same exposure settings as those you used to create the actual image, or “light frame.” I usually take twice as many dark as light frames, then use a free software program called DeepSky Stacker to stack the images and subtract the dark frames. Finally I bring the resultant file into Photoshop and apply a number of other adjustments.

What’s the most distant celestial object you’ve photographed?

A trio of galaxies in the constellation Leo called the Leo Triplet, about 35 million light-years away.

Which of your photographs was the toughest to produce, and why?

The Leo Triplet. With objects that distant and faint, you really need to collect a lot of photons. Without a constant power supply, digital camera batteries won’t last very long—so you’ll never get enough exposure. To truly get enough data you have to spend many, many hours outside. After that experience and many others I went out and bought a portable battery pack, which is really just a modified car battery with 4 cigarette lighter connectors!

You’ve often photographed the bright star of the International Space Station as it moves over your house, sometimes alongside the space shuttle it’s docked to. You’ve even captured it separating from its shuttle. Me, I would be wondering if all those astronauts up there were looking back at me (even though I know, of course, that it’s ridiculous to think so). What are you thinking about while you watch it?

When I first realized you could see the International Space Station and even photograph it I was like, “Dude, that is so awesome!” But really, I’m jealous. I think, wouldn’t it be so cool to be up there, circling the Earth and seeing the world from that perspective? Even more, I think about the amazing progress we as a species have made with our first steps toward space exploration. I think about the laws of physics and how it is gravity that propels something the size of 3 football fields at 27,000 km/h (17,000 mph).

Once or twice in your years of photographing the sky at night you say you think you may have captured noctilucent clouds. What the heck are noctilucent clouds, and why are they so elusive?

Noctilucent clouds are a strange phenomenon. These are very high altitude, tendril-shaped clouds made from water-ice, hovering at 76-85km in altitude. They’re observed during the summer months at latitudes between 50° and 70° above and below the equator. What makes them interesting is that they can only be seen in deep twilight, when the light from the sun below the horizon illuminates them. They appear to have an electric-blue glow. Another interesting fact about them is that they were not observed before 1885 and some scientist theorize that the eruption of the Krakatoa Volcano in 1883 may have precipitated their existence. What’s remarkable is that they are appearing much more frequently now because of global climate change and are sometimes visible at lower latitudes. That’s why I sometimes wonder if I’m seeing them in my photos, because I live just above the 45° latitude line.

Something else you’ve tried to capture is a phenomenon known as Zodiacal light. What’s that? And how did you eventually track it down?

The zodiacal light is a diffuse cone of light visible in the West after sunset and before sunrise in the East, the best times being spring in the West and fall in the East. You need a remarkably dark sky to see it with the naked eye but a camera can pick it out in relatively dark rural skies. What it is is reflected sunlight from the dust particles left over from planet formation 4.6 billion years ago in the inner solar system. I’ve been intrigued by it since I was a kid, and once I understood the definition of twilight, I managed to get some nice photos of it by timing the moment with clear skies and no moonlight. Brian May, the guitarist from Queen, earned his Ph.D in astrophysics in 2007 with a thesis studying the velocities of particles in the zodiacal dust. It took him over 30 years to do it but nonetheless it makes that particular astronomical phenomenon even more sexy in my book!

Something that surprised me was that you don’t always shoot at night. What’s the story with your “analemma” photographs of the sun?

One of the most interesting aspects of studying the sky is that you will notice the paths of solar system objects vary over time, often in a regular fashion. This is because as the Earth revolves around the sun it also spins on a tilted axis of 23°, which, by no accident, matches the Tropics of Cancer and Capricorn. This tilt causes a visual illusion: the sun appears in a different position of the sky at the same time each day, say at noon. Over time, in any 365 day period, the sun will appear to trace a closed path in a figure-eight pattern. When you photograph the sun this way from the same spot on Earth and superimpose each image you will see a pattern known as an analemma. The shape of the analemma will vary depending on your latitude and typically looks like a flattened bowling pin!

What exactly are we seeing in this photo below? It’s amazing.

Everybody seems to love star trails and this is a good example of that. To make this photo, I took 114 thirty-second exposures, and then layered them together. You can tell it was taken in the northern hemisphere because all the star trails appear to circle around a fixed point. That fixed point is the North Star, also known as Polaris, the last star in the handle of the Little Dipper. What does this mean? Ironically, it provides evidence that the Universe revolves around the Earth! In the middle, you can also see the path traced by the International Space Station.

In urban areas, light pollution is a huge problem at night—I can’t remember the last time I saw more than one or two stars. What’s it like where you live? And are there any camera tricks that can help city-dwelling astrophotographers cut through the glow?

I live in a smallish city of about 90,000, located 90 minutes from Toronto. Comparatively the sky here is darker than in Toronto, but not by much. I can only see the Milky Way with a camera and even that requires a lot of post-processing to enhance. But, just 20 minutes drive away from town affords dark enough skies that the Milky Way becomes naked-eye visible. That said, I have been able to image the Andromeda Galaxy from my backyard in the city even though it is almost impossible to see with the naked eye there. To reduce the glow of light pollution, I use a filter designed to cut off light wavelengths from mercury, neon and sodium street lights.

One other thing that budding astrophotographers need to be aware of is that DSLRs have an infrared-blocking filter over the sensor. It prevents you from imaging any object that emits a lot of hydrogen gas, like many nebulae. So if you’re trying to photograph something and it’s not showing up, that might be why. (This is not a problem with film cameras.) You can fix this by removing the IR filter and there are a few companies that specialize in the removal or modification of your camera for this purpose.

When do you sleep?

Sleep? What’s that?