The Lunar Eclipse, to True Scale

By: Alan Dyer

Oct 04 2015

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Category: Eclipses & Transits

1 Comment

Focal Length:35mm
Shutter:1/1 sec
Camera:Canon EOS 6D

My multiple-exposure composite shows the complete September 27, 2015 total lunar eclipse to true scale, with the Moon accurately depicted in size and position in the sky.

From my location at Writing-on-Stone Provincial Park in southern Alberta, Canada, the Moon rose in the east at lower left already in partial eclipse.

As it rose it moved into Earth’s shadow and became more red, while the sky darkened from twilight to night, bringing out the stars.

Then, as the Moon continued to rise higher it emerged from Earth’s shadow, at upper right, and returned to a brilliant Full Moon again, here overexposed and now illuminating the landscape with moonlight.


The disks of the Moon become overexposed in my composite as the sky darkened because I was setting exposures to show the sky and landscape well, not just the Moon itself. That’s because I shot these frames – and many more! – primarily for use as a time-lapse movie where I wanted the entire scene well exposed in each frame.

Indeed, for this still-image composite of the eclipse from beginning to end, I used just 40 frames taken at 5-minute intervals, selected from 530 I shot, taken at 15- to 30-second intervals for the full time-lapse sequence.

All were taken with a fixed camera, a Canon 6D, with a 35mm lens, to nicely frame the entire path of the Moon, from moonrise at lower left, until it exited the frame at top right, as the partial eclipse was ending.

In the interest of full disclosure, the ground comes from a blend of three frames taken at the beginning, middle, and end of the sequence, and so is partly lit by twilight and moonlight, to reveal the ground detail better than in the single starlit frame from mid-eclipse. Lights at lower left are from the Park’s campground.

The background sky comes from a blend of two exposures: one from the middle of the eclipse when the sky was darkest, and one from the end of the eclipse when the sky was now lit deep blue. The stars come from the mid-eclipse frame, a 30-second exposure.


So, yes, this is certainly a composite assembled in Photoshop – a contrast to the old days of film where one might attempt such an image just by exposing the same piece of film multiple times, usually with little success.

However … the difference between this image and most you’ve seen on the web of this and other eclipses, is that the size of the Moon and its path across the sky are accurate, because all the images for this composite were taken with the same lens using a camera that did not move during the 3-hour eclipse.

This is how big the Moon actually appeared in the sky in relation to the ground and how it moved across the sky during the eclipse, in what is essentially a straight line, not a giant curving arc as in many viral eclipse images.

And, sorry if the size of the Moon seems disappointingly small, but it is small! This is what a lunar eclipse really looks like to correct scale.

By comparison, many lunar eclipse composites you’ve seen are made of giant moons shot with a telephoto lens that the photographer then pasted into a wide-angle sky scene, often badly, and pasted in locations on the frame that usually bear no resemblance to where the Moon actually was in the sky, but are just placed where the photographer thought would look the nicest.

You would never, ever do that for any other form of landscape photography, at least not without having your reputation tarnished. But with the Moon it seems anything is permitted, even amongst professional landscape photographers.

No, you cannot just place a Moon anywhere you like in your image, eclipse or no eclipse, then pass it off as a real image. Fantasy art perhaps. Fine. But not a photograph of nature.

Sorry for the rant, but I prefer accuracy over fantasy in such lunar eclipse scenes, which means NOT having monster-sized red Moons looming out of proportion and in the wrong place over a landscape. Use Photoshop to inform, not deceive.

– Alan, October 4, 2015 / © 2015 Alan Dyer / 


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