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

H alpha wavelength

16:25 UT   20th Aug 2006

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)

 

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  9th September 2006

Ca K wavelength

13:45 UT   9th September 2006

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.

 

Ha wavelength

11:45 UT   9th September 2006

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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