Fe XIV 530.3 nm (green), Fe XI 789.2 nm (red) and continuum (white)

This color image is a composition of 287 eclipse images (calibrated using about 3500 dark-frames and flat-fields) acquired with 6 different instruments - one pair of Nikon D810 cameras for white-light (continuum) images and two pairs of Atik cameras for imaging of Fe XI and Fe XIV emission. Continuum is displayed as neutral gray, Fe XI is presented as red color and Fe XIV as green color.
Charged particles are tracers of magnetic field lines. At present, they are the only tools available to visualize the 'shape' of magnetic field lines in the solar corona, thus yielding an image of their distribution in the plane of the sky. However, there are limitations when using ions, such as Fe XI and Fe XIV, since they populate different magnetic structures with different temperatures. Hence, the image of solar magnetic field structures, which they provide, is incomplete. Fortunately, free coronal electrons, scattering the photospheric light towards the observer, are omnipresent and therefore the visualization the solar magnetic filed in the white-light (continuum) image is detailed and complete. That is why the composition presented in this page provides valuable information about the structure of the solar magnetic field and at the same time visualizes the distribution of Fe ions.
Click on the image or on the following reference to display the higher resolution image version (3.4 MB, PNG format).

Date21. 08. 2017
Time2nd contact 17:21:11 UT, 3rd contact 17:23:14 UT
Placenear Mitchell, Oregon, USA
CoordinateN 44° 31.539',   W 119° 54.459',  Alt. 1100 m
ConditionsClear sky but some smoke from forest fires, solar altitude 43° above horizon
Optics2× TS Photo Line Apochromatic Triplet D=115 mm, f = 800 mm with 2.5 inch flattener
4× Achromat 4/300 mm equipped with following narrow band filters:
  On-band filter: Andover, center wavelength: 530.3 nm, bandwidth 0.5 nm
  Off-band filter: Andover, center wavelength: 527.3 nm, bandwidth 0.5 nm
  On-band filter: Andover, center wavelength: 789.2 nm, bandwidth 0.5 nm
  Off-band filter: Andover, center wavelength: 786.1 nm, bandwidth 0.5 nm
Camera2×Nikon D810 (continuum), 2×Atik 314L (Fe XIV) and 2×Atik 414EX (Fe XI)
Exposure1/1000 - 4 s (continuum), 0.05 - 6.4 s (Fe XIV and Fe XI)
ProcessingComposition of 287 eclipse images (Continuum: 161, Fe XIV: 32 On-band and 32 Off-band, Fe XI: 31 On-band and 31 Off-band,) taken with 4 cameras. 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 emission by subtracting the Off-band images, than resulting image was processed using Corona 5.0 software in order to visualize coronal structures. Final processing was done using ACC 6.1 software.
Image processing by Miloslav Druckmüller
SoftwareAstro D3F 2.0, PhaseCorr 7.0, LDIC 6.0, Corona 5.0, Sofo ACC 6.1
Copyright© 2017 Miloslav Druckmüller, Peter Aniol, Shadia Habbal, Pavel Štarha, Judd Johnson,
    Jana Hoderová

Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
Page last update: 11.6.2018