Slitless spectrum of the solar corona

This spectrum was taken with a slitless spectrograph 12 seconds before the third contact. In this moment not only corona was visible, but the upper chromosphere started to be visible as well. That is why the image contains not only coronal spectral lines. The spectrum of the corona is dominated by two forbidden emission lines of highly ionized iron - Fe XIV line at 530.3 nm and Fe X at 637.4 nm. The upper chromosphere spectrum and spectrum of prominences consists of hydrogen Balmer series lines at 656.3 nm, 486.1 nm and 434.0 nm and two helium lines at 587.6 nm and 447.1 nm. Small dots in the green part of the spectrum are caused by magnesium line triplet at 516.7 - 518.4 nm. The diffraction grating which enabled this experiment was lent from Robert Slobins. The diffraction grating was placed in front of a 300 mm lens and the second order spectrum was captured. The modified Canon EOS 5D with extended red sensitivity enabled to record the spectrum as far as H-alpha line. The experiment was separated from other cameras and was placed on a small EQ 5 mount and the camera was controlled manually.
Click on the image or on the following reference to display the higher resolution image version (920 KB, PNG format).

Date11. 07. 2010
Time18:49:53 UT, 12 s before the third contact
PlaceTatakoto Atoll, French Polynesia
CoordinateS 17° 20' 39.3'',   W 138° 27' 3.1'',  Alt. 6 m
ConditionsPartially clear, partially thin clouds
OpticsTamron 70-300 mm 1:4-5.6 LD (set to 5.6/300 mm) with diffraction grating in front of the lens, the second order spectrum was used
CameraModified Canon EOS 5D with Baader IR-UV cut filter (ISO 100)
Exposure4 s
ProcessingDark frame and sky background were subtracted
SoftwareSofo ACC 6.1
Copyright© 2010 Miloslav Druckmüller

Miloslav Druckmüller
Institute of Mathematics, Faculty of Mechanical Engineering
Brno University of Technology, Czech Republic
Page last update: 5.8.2014