The Sun in He I

The Sun in He I, observed by SUMER 02.-04.Mar.96

[Full Picture]

The Sun seen in in the emission line of Helium I at 584.334 Å (chromosphere, temperature 20 000 K). As can clearly be seen, the picture was put together from eight horizontal raster scans in alternating directions, starting in the solar NE. Each raster scan includes 1600 exposures, lasting 7 seconds each. The picture is shown in bins of 4x4 pixels, one pixel being approx. 1 arcsec².

Some image corrections were performed (flat-field correction on-board, elimination of a 2-pixel and a 7-pixel period on-ground). Most data faults were eliminated by replacing them with the average of their neighbors (approx. 7 per 1600 raster steps).

The brightest pixels correspond to an intensity of more than 70 counts/line/arcsec² (with a maximum of approx. 200), while the average is around 10.

Spectral window

Shown is the spectral window on the detector (left), averaged over one horizontal scan, and the average profile of the He I line (right).

In the 25(spectral)x360(local) pixels selected and transmitted from the 1024x360 detector plane of the spectroscope, the image of the 300x1 arcsec² slit can be observed, covering 295 local pixels in N-S-direction plus some stray light. The spectral pixels correspond to 0.022 Å (2nd order). The profile shows counts/pixel/s versus wavelength in Å.

Details

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