The Rising of the Harvest Moon


On two clear evenings the Harvest Moon rose red and and large over the Alberta prairie.

I present a short music video (linked to below) of time-lapse sequences of the Harvest Moon of 2020 rising. I shot the sequences through a small telescope to zoom in on the Moon’s disk as it rose over the flat horizon of the prairie near where I live. I love being able to see the horizon!

Note the effects of atmospheric refraction squishing the Moon’s disk close to the horizon. The Moon becomes more normal and spherical as it rose higher.

People sometimes think the refraction effect is responsible for making the Full Moon appear large on the horizon, but the atmosphere has nothing to do with it. The effect is strictly an optical illusion. The Moon is no bigger on the horizon than when it is higher in the sky.

The photo below shows a composite of images taken September 30, 2020.

The rising of the nearly Full Moon, the Harvest Moon of 2020, on September 30, from a site near home in Alberta, looking just south of due east this night. Refraction distorts the disk and atmospheric absorption reddens the disk toward the horizon. This is a multiple exposure composite of 6 images with the Canon 6D MkII through the 80mm A&M apo refractor at f/6 without field flattener. Taken as part of a time-lapse sequence with images every 2 seconds. The frames for this blend were taken 2 minutes apart, so selected from every 60 frames out of the sequence. All were at 1/8 second at ISO 100. Images stacked in Photoshop and blended with Lighten mode. The ground comes from the first image.

Note in the image below, from October 1, how much redder the Moon appears. That’s the effect of atmospheric absorption, in this case from dust and smoke in the air dimming and reddening the Moon (the same happens to the rising or setting Sun). At times this evening it looked like the Moon was in a total eclipse.

The Harvest Moon (the Full Moon of October 1, 2020) rising almost due east at the end of a country road in southern Alberta, near home. The horizon was smoky or dusty, so the Moon was very red as it rose, and looking almost like a totally eclipsed Moon. This is a blend of 6 exposures, all 1/2-second with the A&M 80mm f/6 apo refractor (for 480mm focal length) and Canon 6D MkII at ISO 400, taken as part of a 460-frame time-lapse sequence, with shots every 2 seconds. For this composite I choose 6 images at 2-minute intervals, so the Moon rose its own diameter between frames. The ground comes from the first image in the sequence when the lighting was brightest. The Moon rose at 7:35 pm this night, about 30 minutes after sunset. A mild Orton glow effect added to the ground with Luminar 4.

Below is the link to the time-lapse music video on Vimeo. It is in 4K. I used Adobe Camera Raw, Adobe Bridge, and LRTimelapse to process the component images as raw files for the time-lapse sequences, as per tutorials in my Nightscape and Time-Lapse ebook, above.

Thanks for looking! Clear skies!

— Alan / © 2020 www.amazingsky.com

The Green Flash – At Last!


The Green Flash (Nov 15, 2013) from Barbados

At last, I enjoyed a successful attempt to capture the elusive green flash.

During three weeks at sea attempts almost every evening from the ship to sight the green flash always failed, as the Sun set behind low horizon cloud.

But this night, the Sun set into the ocean with a clear horizon. My location was a small public oceanside walkway on Bay Street near Bridgetown, Barbados. It was a great spot to watch the sunset, though our main purpose for stopping there was to pick up some fried chicken at the KFC just steps away!

But the imminent sunset under ideal conditions made it worthwhile sticking around to see if we (I was with two friends from Alberta) could sight the green flash.

We did! I shot a rapid fire sequence – the image above is one frame of many catching the last bit of the Sun remaining above the horizon and turning green.

The infamous green flash is a refraction effect caused by the atmosphere separating out the green light and lifting it higher so it’s the last thing you see as the Sun sets. Conditions aren’t always amenable to seeing the green flash – you need a clear horizon and you also need the atmosphere structured with warm layers near the sea creating a mirage effect.

For more details on the technical explanations see Andrew Young’s page at http://aty.sdsu.edu/ 

… and Les Cowley’s page at http://www.atoptics.co.uk/atoptics/gf1.htm 

Andrew Young has a nice simulation at http://aty.sdsu.edu/explain/simulations/inf-mir/inf-mirSS4GF.html

Sunset from Barbados (Nov 15, 2013)

This was the view moments before, with the lower edge of the setting Sun distorted by atmospheric refraction, a sign that you might see a green flash as the upper edge disappears.

Sunset & Sailing Boat from Barbados

I shot this image a few minutes earlier as a photogenic sailboat drifted into the scene. Red sails in the sunset!

I’m nearing the end of my stay in Barbados and my 4 weeks away from home. There are heavy snowfall warnings out for southern Alberta this weekend so I’m not anxious to return! But winter will be waiting for me next week.

– Alan, November 16, 2013 / © 2013 Alan Dyer