Chasing the Shadowed Moon

The tradition continued of chasing clear skies to see a lunar eclipse.

It wouldn’t be an eclipse without a chase. Total eclipses of the Sun almost always demand travel, often to the far side of the world, to stand in the narrow path of the Moon’s shadow. 

By contrast, total eclipses of the Moon come to you — they can be seen from half the planet when the Full Moon glides through Earth’s shadow. 

Assuming you have clear skies! That’s the challenge. 

Of the 14 total lunar eclipses (TLEs) visible from here in Alberta since 2000, I have seen all but one, missing the January 21, 2000 TLE due to clouds. 

But of the remaining 13 TLEs so far in the 21st century, I watched only three from home, the last home lunar eclipse being in December 2010. 

I viewed three TLEs (August 2007, February 2008, and December 2011) from the Rothney Observatory south-west of Calgary as part of public outreach programs I was helping with. 

In April 2014, I was in Australia and viewed the eclipsed Moon rising in the evening sky over Lake Macquarie, NSW. 

A year later, in April 2015, I was in Monument Valley, on the Arizona-Utah border for the short total eclipse of the Moon at dawn. 

But of the eclipses I’ve seen from Alberta since 2014, I have had to chase into clear skies for all of them — to Writing-on-Stone Provincial Park in both October 2014 and September 2015, to the Crowsnest Pass for January 2018, and to Lloydminster for January 2019. 

The total lunar eclipse on the morning of May 26, 2021 was no exception. 

Leading up to eclipse day prospects for finding clear skies anywhere near home in southern Alberta looked bleak. The province was under widespread cloud bringing much-needed rain. Good for farmers, but bad for eclipse chasers.

Then, two days prior to the eclipse a hole in the clouds was predicted to open up along the foothills in central Alberta just at the right time, at 4 a.m. The predictions stayed consistent a day later. 

So trusting the Environment Canada models that had served me well since 2014, I made plans to drive north the day before the eclipse to Rocky Mountain House, a sizeable town on Highway 11 west of Red Deer, where the foothills begin. “Rocky” was predicted to be on the edge of the clearing, with a large swath of clear sky in the right direction, to the southwest where the Moon would be.

Fortunately, COVID restrictions are not so severe here as to demand stay-at-home orders. I could travel, at least within Alberta. Hotels were open, but restaurants only for takeaway.

This was going to be a tough eclipse even under the best of sky conditions, as for us in Alberta the Moon would be low and setting into the southwest at dawn. The Moon would be darkest and in mid-eclipse just as the sky was also brightening with dawn twilight. 

However, a low eclipse offers the opportunity of a view of the reddened Moon over a scenic landscape, in this case of the eclipsed Moon setting over the Rockies. That was the plan.

Unfortunately, Rocky Mountain House wasn’t the ideal destination as it lies far from the mountains. I was hoping for a site closer to the Rockies in southern Alberta. But a site with clear skies is always the first priority.

The task is then finding a spot to set up with a clear view to the southwest horizon, which from the area around Rocky is tough — it’s all trees! 

This is where planning apps are wonderful. 

I used The Photographer’s Ephemeris (TPE) to search for a side road or spot to pull off where I could safely set up and be away from trees to get a good sightline to the horizon and possibly distant mountains. 

A site not far from town was ideal, to avoid long pre- and post-eclipse drives in the wee hours of the morning. The timing of this eclipse was part of the challenge — in having to be on site at 4 a.m.

TPE showed several possible locations and a Google street view (not shown here) seemed to confirm that the horizon in that area off Highway 11 would be unobstructed over cultivated fields. 

But you don’t know for sure until you get there. 

So as soon as I arrived, I went to one site I had found remotely, only to discover power lines in the way. Not ideal.

I found another nearby side road with a clean view. From there I used the PhotoPills app (above) and its augmented reality “AR” mode to confirm, that yes, the Moon would be in the right place over a clear horizon at eclipse time the next morning. 

Another app I like for site scouting, Theodolite, also confirmed that the view toward the eclipsed Moon’s direction (with an azimuth of about 220°) would be fine from that site. 

As a Plan B — it’s always good to have a Plan B! — I also drove west along Highway 11, the David Thompson Highway, toward the mountains, in search of a rare site away from trees, just in case the only clear skies lay to the west. I found one, some 50 km west of Rocky, but thankfully it was not needed. The Plan A site worked fine, and was just 5 minutes south of town, and bed!

I set up two tripods. One was for the Canon R6 with an 85mm lens for a “time-lapse” sequence of the Moon moving across the frame as it entered the Earth’s umbral shadow. 

The other tripod I used for closeups of just the Moon using the Canon 60Da and 200mm lens, then switched to the Canon Ra and a 135mm lens, then the longer 200mm lens once the Moon got low enough to also be in frame with the horizon. Those were for the prime shot of the eclipse over the distant mountains and skyline. 

It all worked! The sky turned out to be clearer than predicted, a pleasant surprise, with only some light cloud obscuring the Moon halfway through the partial phases (the first image at top). 

The other surprise was how dark the shadowed portion of the Moon was. This was a very short total eclipse, with totality only 14 minutes long. With the Moon passing through the outer, lighter part of the umbral shadow, I would have expected a brighter eclipse, making the reddened Moon stand out better in the blue twilight.

As it was, in the minutes before the official start of totality at 5:11 a.m. MDT, the Moon effectively disappeared from view, both to the eye and camera. 

My best shots were of the Moon still in partial eclipse but with the umbral shaded portion bright enough to show up red in the images. The distant Rockies were also beginning to light up pink in the first light of dawn. 

My last view was of a sliver-thin Moon disappearing into Earth’s shadow just prior to the onset of totality. I packed up and headed back to bed with technically the Moon still up and in total eclipse, but impossible to see. Still I was a happy eclipse chaser! 

It was another successful eclipse trip, thwarted not so much by clouds, but by the darkness of our planet’s shadow, which might have been due to widespread cloud or volcanic ash in the atmosphere of Earth. 

The other factor at play was that this was a “supermoon,” with the larger Moon near perigee entering more deeply into the umbra than a normal-sized Moon. 

The next lunar eclipse is six months later, on the night of November 18/19, 2021 when the Moon will not quite fully enter Earth’s umbral shadow, for a 97% partial eclipse. But enough of the Moon will be in the dark umbra for most of the Moon to appear red, with a white crescent “smile” at the bottom. 

As shown above, from my location in Alberta the Moon will appear high in the south, in Taurus just west of the Milky Way. The winter stars and Milky Way will “turn on” and fade into view as the eclipse progresses.

We shall see if that will be a rare “home” eclipse, or if it will demand another chase to a clear hole in the clouds on a chilly November night. 

— Alan, © 2021 amazingsky.com