GUEST BLOG - Huzefa Mehta
This post is at the time of an bi-annual astronomical event, solstice. It's an appropriate time to talk about astronomy. On Monday August 21, 2017, there was a rare astronomical event that was seen from across the US mainland - a long lasting total solar eclipse. That means 100% of the sun’s face is obscured by the moon as seen from a point on earth.
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| Totality features: all photos are from totality except the one of sun's surface (second from center). The last sun image is HDR of the Corona. |
My guest blogger is Huzefa Mehta, who travelled to St. Louis, Missouri, and then to St. Clair (about 50mi southwest of St. Louis) to observe and photograph the rare event. This post features his photos - and they are real gems, capturing a momentary event into images that display various facets of the eclipse, and for us to enjoy year after year.
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| Lucy in the sky with diamonds:
Thanks to R. Mehta for reading me [Huzefa] out the settings (http://www.mreclipse.com/SEphoto/image/SE-Exposure1w.GIF ) during totality. Had three cameras pointed to the sky, a dedicated solar telescope and camera and a drone. Almost 2:31 of totality! |
Huzefa used two land cameras and one drone camera. With different lens settings, and aid of software post-processing, he uncovered the details of the eclipse that our human eye is unable to see. He was lucky with the weather considering thunderstorms were forecasted for the afternoon. The photos below show solar flares, the sun’s fiery surface with flares (my favorite), the sun’s corona (another favorite), and other facets. The facets are shown in the same order as seen in the montage "Totality features" (first image above).
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| Solar flares 1 |
What was rare and exceptional about this particular event? The combination of 1. 100% totality, and 2. long duration from start to end of 7 min 32 sec, and totality lasting a maximum of 2 min 40 sec (at a location slightly south of Carbondale, Illinois, in Giant City State Park).
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| Sun's surface and flares: via a 15sec stacked video (camera ASI120MM) through H-alpha telescope (Coronado, Solarmax 60), maybe 20 minutes before totality. Processed in Registax. Glad to get some surface detail and a few flares. |
How rare is rare? The previous total solar eclipse in the continental US was in 1979 (38 years prior to the 2017 event). The next total solar eclipse whose totality approaches 7 minutes will occur in 2132 (215 years after the 2017 event). There will be several other total solar eclipses visible from US in between now and 2132, but they will be of much lesser magnitude than the 2017 eclipse.
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| Solar flares 2 |
This article is posted near the date of another astronomical event, the June solstice is the longest day of the year for those in the northern hemisphere, we call it summer solstice.
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| Diamond ring at totality |
Can summer and and winter solstice occur on the same day? Yes, the day of the June solstice is also the shortest day of the year in the southern hemisphere (winter solstice). The December solstice is the reverse of the June solstice.
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| Sun's corona : High dynamic range of the corona. It involves stacking images of different exposures and applying the Larsen-Sekania filter (think it is some kind of Gaussian Blur) and then combining the original stack and the filter. There is a bit of manual work and estimation when choosing the exact center of images to be stacked and during filtering. Finally some histogram stretching to bring back the color. |
As a bonus, every state in the continental US experienced at least a partial eclipse. The center line, or the path of 100% totality, made first contact in Oregon, and exited at South Carolina.
My crude attempt to indirectly view the eclipse. Used pinhole puncture in index card to focus sunlight and cast image of solar eclipse. This was in Bay Area, with maximum lunar coverage of the sun at about 70%.
Additional Photographic Notes
- All totality Features: 2x600mm, f/13, ISO100. Baileys Beads 1/2000s, Chromosphere 1/1000s, Prominences 1/500s, Corona sweep between 1/125s-8s
- Lucy in the sky with diamonds: ƒ/131/8850mmISO10
- Solar flares 1: 1/2500s, 100ISO, f/13
- Solar flares 2: 1/2500s, 100ISO, f/13
- Solar flares 2: 1/2500s, 100ISO, f/13
- Diamond ring: ƒ/131/25850mmISO100
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