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Total Solar Eclipse of 12 August 2026 Spain, Villahoz, Ermita de la Virgen de Matrigal, +42°05'30.5" N, 3°54'16.3" W, 848 m a.s.l. Local circumstances: C1 17.33.49, C2 18.28.52, max 18.29.45, C3 18.30.37, Sunset 19:21 (effective 19.15), C4 19.22.12 UT, duration 1 min 45 s by Lorenzo Comolli |
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| Sequence of
the full eclipse from C1 to sunset captured on a single
image at 3-minute intervals. This is a classic goal for
eclipse astrophotography, which at the time of film
photography was captured on a single piece of film, and
now with digital imaging is compiled from many frames
added together via software with the strict requirement
that camera pointing remains fixed. Sequence obtained with a modified Canon 6D (Baader), Canon 50 mm f/1.8 lens used at f/5.6, exposure 1/13 s during C1-C2 partiality and 0.6 s or 5 s during C3-C4 (with solar filter D=6) and HDR of 1/13-0.6-5 s during totality (without filter), ISO 100, 3 min intervals. Because the framing of totality was not perfectly centered in the frame, I slightly expanded the field on the left using a reference image taken outside of the eclipse, so that the image retains the real landscape. |
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| Lorenzo
Comolli (me) and my friend Emmanuele Sordini in a group
photo taken during totality. This was a key objective of
our expedition, something to take with us in the future
as a reminder of the expedition. Taken near
mid-totality, with the eclipsed Sun behind, with Venus
visible at the top-left, showing my setup on the left
(TEC140), the authors in the middle (Lorenzo and
Emmanuele), Emmanuele's setup on the right (Pentax 75)
and on the far right our friends Giuseppe, Valeria,
Barbara, Luisa. HDR composition obtained at mid-totality with a Canon 6D, Samyang 14 mm f/5.6, exposure 0.2-0.8-3.2 s, ISO 800. |
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| An all-sky
shot captures all the sky in a single image, a very
important feature when the time is limited like during
totality! HDR composition obtained near mid-totality with a modified Canon 5D (Baader), Peleng 8 mm f/5.6, exposure 0.4-1.6-6 s, ISO 800. |
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| Rectangular projection
of the above all-sky image. The orange horizon is mainly
on the left and right of the totality. My setup (TEC140)
is at the left and Emmanuele's setup (Pentax 75) at the
right, while Emmanuele and I are posing for the group
photo with the 14 mm lens. |
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A solar
eclipse greatly influences Earth's atmosphere. The
temperature, relative humidity, and luminance data show
typical trends, peculiar to each eclipse and location.
During this eclipse I used a T/RH datalogger with the sensors positioned at 1 meter in height on a small tree, with sensors shaded from direct sunlight. For this eclipse I recorded only a 2°C decrease relative to the trend, to be compared to 5°C in 2024 in Arkansas, USA, 9°C in 2017 in Wyoming, USA, to 4°C in Egypt 2006, to 7°C in Hungary 1999. Clearly the eclipse near the horizon greatly reduced the temperature drop. A digital luxmeter measured the horizontal luminance: this is a really interesting measurement, which shows the tremendous fall in light, dropping between full Sun at 30000 lux at C1 and totality at only 1.7 lux (to be compared to 1.8 lux in Arkansas 2024, 3.4 lux in Wyoming 2017, 4.1 lux in Egypt 2006). The value is the lower of my measurements, clearly due to the low altitude Sun, but in truth I expected much lower due to this; this is nearly similar to Arkansas 2024 with the eclipse very high in the sky. Maybe the shorter duration of the totality (only 1 min 45 s) was the key factor. To be better understood! During totality I measured the sky brightness with an SQM-L, obtaining 14.29 mag/arcsecē, which is equivalent to the twilight sky when the Sun's altitude is -6°, i.e. civil twilight. Do you want to know how dark the sky is during totality? Wait for civil twilight, that is about 30 minutes after sunset! Here are the plots of:
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 Click for the PDF presentation |
| If
you're interested in processing your HDR corona, I invite
you to follow the tutorial that Lorenzo Comolli prepared
after the 2017 USA eclipse. On January 27, 2018 Lorenzo
was invited by the VVS association in Belgium to present
at the Astrofotografiedag 2018, a conference about
astrophotography. One of the presentations was on how to
process the great American eclipse. Look
also at the other presentation on the dedicated page. |
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