Partial Eclipse at Sunset - 4th December 2021


Partial Eclipse at Sunset - 4th December 2021

The total solar eclipse on offer in 2021 was one for the adventurous (and wealthy) - it occurred over Antarctica and the surrounding ocean. There were just a handful of places available on the continent, plus a few cruiseships gambling with the Southern Ocean weather and a couple of eclipse flights leaving from Punta Arenas, Chile (plus others planned from Argentina and Melbourne that did not go ahead). It had not even crossed my mind to join any of these expeditions.

However, I did notice that the edge of the partial eclipse zone just touched southern Victoria (and Tasmania and New Zealand). While this meant just a few percent of the sun would be eclipsed, it did place the timing at sunset which creates much more interesting photographic opportunities than a simple filtered image of the sun high in the sky. So I hoped to give it a try..

NASA map of eclipse zone, showing it just touching south coast of Victoria
(upside down at bottom)

To safely image the sun at sunset, it needs to be setting very low over a distant horizon, ideally the ocean, to extinguish as much of the brightness as possible. And heading south gained an extra percent eclipse compared to latitude around Melbourne (even less in central Vic where I live). Heading east rather than west was also important so that maximum eclipse was at sunset, rather than while the sun was still marginally higher in the sky.

Wilsons Promontory is as far south as you can get in Victoria, and offers attractive views over the ocean with nice foregrounds, including islands out to see. But it has notoriously unreliable weather. And this day was no exception.

I finished work early on the Friday, drove via the campground to drop off the camper-trailer, and then made a bee-line for the Prom in the hope of arriving just in time for sunset. With very little time to setup in the first location with a view, I at least got a chance to rehearse the sequence despite some low cloud obscuring much of the view.

The tail end of a cold front came through during the following day on Saturday, making for grim looking weather - see model image and early afternoon image below. 

Grey skies (and showers) in the early afternoon - typical Prom weather

It felt like I should be heading in a different direction but I sat tight and continued location scouting, trusting that the view over Bass Strait from here would be as clear as I was likely to find anywhere. The forecast was for the Prom to be in as clear an area as anywhere, noting that I was looking for clear sky on the horizon 100-200kms away. Later in the afternoon, the sky looked quite promising.

Skies clearing later in the afternoon, just as forecast

Planning photographic angles for sun to set beside Norman Island
with The Photographer's Ephemeris App

So my Borg 80mm scope ended up high on the side of the road so I could almost squeeze this angle together. And the larger Skywatcher EvoStar 150 and old Canon G12 catching some wide video were about 400 metres back down the road, making for a few hectic trips back and forth setting up and executing the shots. Just noticing the haze on the horizon, I decided to bump up the exposure on the camera before leaving. Unfortunately, the sun went very quickly from overexposed to buried behind the cloud. So you have to look very closely in the video to see the edge of the moon at all. In the Borg image at the bottom of this post, I have merged in the Skywatcher unfiltered image taken at the same time to create a HDR composite that retains some view of the solar disc.

Skywatcher EvoStar 150 with 1.5x extender @1800mm (with solar filter)
Sony A7 III (video frame)

Skywatcher EvoStar 150 with 1.5x extender @1800mm (unfiltered, except by cloud)
Sony A7 III (video frame, 1/4000 sec ISO100)

Borg 80mm @550mm (unfiltered) & HDR composite with some blending of Skywatcher image above
Canon 5D Mark IV (video frame, 1/2000 sec, ISO100)

Satellite image around eclipse time showing
cloud over King Island (left arrow) 200kms west of Wilsons Promontory (right arrow)