April 8 Eclipse In Review

So, it finally happened. After months of prep and work to add solar eclipse features in Photo Ephemeris, we finally got to see the April 8 total eclipse!

We traveled on a no-frills tour to a location near Torreón in northern Mexico. The actual observation site was a football field on a university campus near the town of Bermejillo, a 45 minute coach drive north of Torreón, and just north of the central line. As we drove farther north, things began to look rather worse in terms of clouds. Having set up on the field, I took a short video a few minutes before first contact:

Things continued in this manner for almost the entire time until C2. Occasionally there’d be a glimpse of the partially eclipsed Sun and a cheer would go up from the crowd, the volume rising and falling as the clouds thinned and then regrouped:

From comments around me, a number of photographers were having trouble acquiring focus, given the thickness of the clouds and the fleeting glimpses we were afforded. I was happy to have set up back button focus on my camera: rather than the camera trying to focus every time you half-press the shutter, it only focusses on pressing the separate AF-ON button on the back of the camera.

There’s no faster way to lose focus than attempting to re-focus every shot - particularly for a subject behind moving clouds. Even without clouds present, as the Sun and Moon move through the frame, they can easily drift away from your selected focus point, leaving your camera with nothing to focus on. Instead, with back button focus, you can seize a moment of clarity, press AF-ON, and then leave it well alone.

Manual focus would work too, but I just can’t trust my eyesight to get it right (this was the case even when my vision was very good). Focus peaking certainly helps, but I find the AF system in the Nikon Z8 to be excellent, so I don’t need to rely on manual.

In what felt like a miracle at the time, around 10 minutes before C2, the clouds started to thin out. Looking to the southwest, from where the shadow would be arriving, some small stretches of clear sky began to appear. It was tantalising. Even before the shadow reached us, the sky started to clear - you can see it easily at the start of this iPhone video:

I was photographing the eclipse with a 100-400mm lens with a 1.4× teleconverter at f/8, giving 560mm equivalent focal length. Bracketing with the camera set to 20fps resulted in a LOT of exposures to review - you can hear the artificial shutter sounds in the soundtrack to the video above.

I used the event countdown and notifications in Photo Ephemeris on a spare iPhone - you can hear the polite British voice making calm sounding announcements from time-to-time in the video too. The spare iPhone was mounted on my tripod leg using a ‘gorilla pod’. It was a huge help in keeping track of things photographically and meant I was able to capture everything I wanted, particularly in the moments leading up to second contact, which I’ve found hard to judge timing-wise during previous eclipses.

Short of doing full camera automation, I wouldn’t want to be without timing announcements while photographing an eclipse in future.

The clouds injected an extra degree of uncertainty into exposure settings. I made a last minute decision to remove my solar filter earlier than planned, on the basis that the clouds were for sure providing a degree of extra light reduction. It came off a full 70 seconds before C2 - yes, it was a slightly risky judgement call, but no ill effects to report for my camera. It allowed me to get a series of shots like this, at C2 minus 40 seconds, which shows Baily’s beads already forming at the cusps:

I assembled some of the best frames into the composite you see at the top of the page - the clouds backlit by Baily’s Beads give a great atmospheric look to it, and something very different to the clear skies of 2017.

Here are a few more shots:

Corona and Clouds

This is a stacked blend of 9 exposures to try and bring out some of the structure of the corona. The moving clouds made it tricky, as you can see, but there’s still some nice detail present.

Chromosphere and Prominences

This shows the first moments of the contiguous chromosphere appearing at around 4 o’clock before C3. The large prominences were visible for a long time from around maximum eclipse, by virtue of their size.

Baily’s Beads and Clouds

Here’s a single exposure (seen in the composite above) showing Baily’s Beads at C3. As soon as any of the Sun’s photosphere was exposed again, the back-lighting of the clouds made them much more visible.

It all worked out nicely in the end - although next time, I’d try to reduce my bracketing sequences from 9 frames to maybe 3 or 5 and try to dial the exposure a little more precisely, in order to acquire more data around the critical times of C2 and C3.

It was a wonderful eclipse to see and to photograph - a very different experience from my first in 2017, but just as memorable, and made much more dramatic thanks to the unpredictable weather! In the end, I was very happy to have seen it.