Total Solar Eclipse Report - April 2024 - Torreon, Mexico
Our thanks to Nick James for this report from the University Regional Unit for Arid Zones of the Chapingo Autonomous University, Torreon, Mexico - Nick travels regularly with Astro Trails as one of our tour leaders and expert lecturers.
The solar eclipse of 2024 April 8 came only seven years after the Great American eclipse of August 21, 2017. It was a long one, lasting 4m 28s at the point of greatest eclipse and the path crossed the arid regions of Mexico and Texas where cloud cover statistics based on data from previous years indicated a high probability of seeing it in clear skies. It was bound to be popular.
When planning an observing site many years ahead of an eclipse we only have access to historical climate data and Astro Trails selected two sites based on this. The Mexican site was on a large football field at the University Regional Unit for Arid Zones of the Chapingo Autonomous University near Torreón and the US site was at the Heart of Texas Equestrian Academy, near Valley Mills. The cloud statistics indicated that Torreón was the best point along the track for weather and it was near the point of maximum eclipse so it became an obvious choice.
As eclipse day approached, long-range computer models started to make predictions about actual cloud cover on the day. Several weeks before the eclipse it became apparent that the weather on April 8 would not be following the climate predictions. Significant amounts of cloud were expected in areas that would normally be cloud-free and both our sites, in Mexico and Texas, were potentially affected.
When I arrived in Mexico City on April 1st the skies were beautifully clear. Unfortunately, the forecast for Torreón, around 1,000 km to the northwest was still showing that cloudy weather would arrive on eclipse day. A few days before the eclipse the weather models become quite accurate. For the Chapingo site it was almost certain that there would be a lot of high cloud at eclipse time and possibly some mid-level cloud too. The high-level cloud would still allow us a great view of the eclipse if it was not too thick since the Sun would be very high in the sky at the time of totality but thick mid-level cloud would be very problematic. I gave two briefings to Astro-Trails groups while in Mexico City and a key question was how much cloud there would be. From looking at the models I was hopeful that the thick mid-level cloud would stay away.
A few days before the eclipse, in the beautiful sunshine of Mexico City, I set up my main imaging telescope on the roof of our hotel. I had brought a 70mm refractor and planned to shoot 4K High Dynamic Range video of the eclipse using this and a Sony A7s iii camera. To track the Sun, I had brought a Skywatcher Solarquest mount. This lightweight alt-az mount finds and tracks the Sun using a GPS receiver and a small solar tracking sensor. I had tested it at home and it worked very well with my eclipse setup. I was pleased to see that it had survived the flight and that it was still working in Mexico City.
The day before the eclipse I had an early start and made the long journey to Torreón. For most of the flight the skies were clear but in the last 20 minutes or so we flew into cloud. On arrival, fairly early in the morning, the Sun was only just visible through this thick cloud but, encouragingly, by eclipse time the sky was quite clear apart from some high cirrus. I was hopeful that this behaviour would be repeated the following day. Late that afternoon I travelled out to the University to check out the site and give my eclipse briefing to the students and staff. Since my Spanish doesn’t stretch much beyond ordering food and drink this would have been a challenge but Astro Trails had used some wonderful AI software to automatically translate my English briefing into Spanish. This was really amazing since it actually sounded like me talking fluently in Spanish. It seemed to work really well and the students all laughed in the right places and asked good questions afterwards. Later I got interviewed for the local University TV and they seemed surprised that I needed an interpreter!
That evening the Sun set in a fairly clear sky but by the following morning a lot of low and medium cloud had appeared. I was hopeful that it would be gone by eclipse time. The University is around 30 km from Torreón and unfortunately, there wasn’t any Sun visible at the time I arrived at the site, since the cloud was quite thick.
One of the problems that I had not anticipated with my setup is that the Solarquest mount is basically a paperweight if there is no sun in the sky for it to find. This meant that I was unable to get the telescope pointing in the right direction to get the camera set up and focussed. First contact came and went without any view of the Sun. This was very depressing. Thirty minutes later I had given up hope of seeing anything.
With 20 minutes or so to go to second contact the Sun started to appear from behind the clouds but only for a few seconds each time. I couldn’t get my telescope lined up in those short windows so I was beginning to feel that bringing that mount was a really bad idea. The sky was brightening from the west though as the mid-level cloud thinned. With no more than 10 minutes to second contact the Sun appeared for long enough for me to find it in the telescope using an approach which I would definitely not recommend (basically staring through it with no filters). In the last few minutes, I managed to get the camera focussed and the cloud continued to thin. This was something of a miracle.
As second contact approached, the looming shadow rushed across the clouds above us. The clouds made the passage of the shadow very obvious and it was very dark. As it crossed the Sun, we had the second contact diamond ring and totality had started. Amazingly we could see it! The corona was significantly attenuated by the high cloud but the prominences and the inner corona were nicely visible. There were several prominences visible at second contact. As the Moon moved over the Sun these were covered up and a very large prominence started to appear at around the 5 o’clock position. This was easily visible with the naked eye and showed a lot of detail in binoculars.
Each eclipse is different and the large amount of cloud that we had at this one really brought out the horizon lighting and colours. In addition to my telescope, I had brought along a GoPro camera to record the widefield view. This shows the amazing colours that were visible around the horizon.
I had a third camera running. It was intended to catch Jupiter, Venus and, possibly Comet 12P/Pons-Brooks but the cloud put paid to that.
The four and a half minutes of totality flew by very quickly and the third contact diamond ring was really spectacular. The Sun then lit up all of the high cloud that had been mostly invisible during totality.
When totality was over, we were all elated since only half an hour before most of us had given up hope of seeing it. I went over to the other field where the University students and staff were based. They were just overwhelmed with the experience and I was so happy that they had seen it. If that cloud had delayed only another 10 minutes, they would have had the experience of it getting dark but nothing more. As it was, they now knew why we travel so far to see these things.
This was another great eclipse experience despite the cloud. I don’t think that I have every seen the shadow and the sky colours more clearly and we did get to see totality too, minus the outer corona.
Roll on April 12, 2026!
My eclipse video shot through the telescope is on YouTube here: https://www.youtube.com/watch?v=npGlwH2mBLs
