SPECTROSCOPY
LHIRES
III IN
SPECTROHELIOGRAPH MODE
The LHIRES III high resolution spectrograph
can be used to produce images of the Sun at any wavelength by allowing the sun
to drift across the field of the instrument and building up an image from
slices extracted from the spectrum at the desired wavelength.
The reconstruction from the continuous stream
of images from the camera is done using software such as Astrosnap (v2.2 beta
onward) or IRIS. Astrosnap can build up
the image in real time. IRIS has sophisticated correction options to cope with
out of square or curved spectral lines.
FIRST
LIGHT th August 2006
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H alpha wavelength LHIRES III 2400 l/mm Bandwidth 2 pixels (approx 0.15A) 80mm f5 refractor stopped down to 45mm (f 8.9) Toucam Pro webcam 5fps Scanned image produced using Astrosnap v2.2 beta software A small prominence is visible at upper right (magnified 2x in the insert) |
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Raw frame from video The RA motor is stopped and the Sun is allowed to drift across the field of view. The bottom edge of the Sun is visible at the top of the frame. The broad central line is the H Alpha absorption line at 6563A This is selected from each frame of the video and built up into an image. A small prominence is visible at the H alpha wavelength. Absorption lines are also visible in the background due to the sky and scattered and leaked light within the instrument. |
CALCIUM
K & H ALPHA IMAGES
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Ca K wavelength LHIRES III 2400 l/mm Bandwidth 2 pixels (approx 0.3A) 80mm f5 refractor stopped down to
45mm (f 8.9) SC3 B+W Vesta webcam 10fps Camera rotated to scan in CCD short direction allowing full width of solar
disc to be imaged. Scanned image produced using Astrosnap v2.2 beta software The slight off axis oblateness is probably due to a error in the
orientation of the orientation of the
spectrograph relative to the scanning direction. |
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Ha wavelength LHIRES III 2400 l/mm Bandwidth 2 pixels (approx 0.15A) 80mm f5 refractor stopped down to
45mm (f 8.9) SC3 B+W Vesta webcam 10fps Camera rotated to scan in CCD short direction allowing full width of solar
disc to be imaged. Image produced using IRIS software to correct line shape and Astrosnap
v2.2 beta software to produce scan mosaic |
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