Fe XIII, 1074.7 nm
Imaging the emission from 12-times ionized iron is extremely challenging when using
silicon-based CCD or CMOS sensors, because the wavelength of 1074.7 nm lies at the very edge of their
sensitivity range. Even though the on-band image is contaminated by continuum the contamination is
lower than contamination of Fe X, Fe XI and Fe XIV on-band images. The reason is that photosphere
irradiance at 1074.7 nm is weaker, for example it is the third of irradiance at 530.2 nm (Fe XIV).
See the following pair of images. The left image was taken through a narrow band filter (bandwidth 1 nm)
with a transmission band centered on the Fe XIII 1074.7 nm emission line. The right image was taken
through a filter with transmission band outside the Fe XIII line in the continuum. It is necessary
to make a precise photometric calibration of all images and then subtract the continuum - the right
image from the left one. You may see these two images as an
animation.
Click on the image or on the following reference to display the
higher resolution image version (908 KB, PNG format).
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| Image | TSE_2026_FeXIII.png |
| Date | 12. 08. 2026 |
| Time | 2nd contact 18:28:24 UT, 3rd contact 18:30:04 UT |
| Place | Pico Trigaza, Spain |
| Coordinate | N 42° 16.0667', W 3° 15.4383', Alt. 1655 m |
| Conditions | Clear sky, solar altitude only 7° above the horizon |
| Optics | System equipped with IR 950 nm blocking filters and following narrow band filters:
on-band filter: Alluxa, center wavelength 1074.7 nm, bandwidth 1 nm
off-band filter: Alluxa, center wavelength 1067.7 nm, bandwidth 1 nm |
| Camera | 2× Atik 414EX |
| Exposure | 10 s, 30 s, 30 s, 10 s |
| Processing | Composition of 8 eclipse images (4 on-band and 4 off-band). Images were calibrated by means of dark frames and flat-fields, aligned by means of phase correlation, composed by means of LDIC 6.0 software, continuum was removed from Fe XII emission by subtracting the off-band images. The resulting image was processed using Corona 5.0 software in order to visualize coronal structures. The final processing was done using ACC 6.1 software.
Image processing by Miloslav Druckmüller |
| Software | PhaseCorr 8.0, LDIC 6.0, Corona 5.0, Sofo ACC 6.1 |
| Orientation | Image has Solar North on top orientation |
| Copyright | © 2026 Miloslav Druckmüller, Shadia Habbal, Peter Urgoš, Martin Šebek |
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Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
druckmuller@fme.vutbr.cz
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Page last update: 3.11.2026
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