Order-zero image (FeXII 195A)#
Use TRACE data: tri20080107.0600 (reversed color table)
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Order-plus image (FeXII 195A)#
Use EIS data: eis_l0_20080107_062226.fits.gz (reversed color table)
40" slot, 15 scans, time duration: roughly 3 minutes
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EIS and TRACE Image alignment#
- Define common Field of View (FOV) for both TRACE and EIS image (FeXII line) - illustrated by dash box.
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- After alignment, the order-zero and order-plus images are as follows:
Order-0 (reversed color table)
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Order-1 (reversed color table)
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Deconvolution results#
- Recontructed velocity map (full FOV)
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EIS did 1" scanning 6 hours before the 40" slot obervation, which covering the small FOV of the 40" slot-scan image - illustrated by dash box.
click here to see EIS data list
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The deconvolution is also applied to this small FOV of the image.
- Recontructed Velocity map (small FOV)
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- Compared with the velocity map (FeXII 195A line) obtained from the EIS data (small FOV):
Use EIS data: eis_l0_20080107_002701.fits.gz
1" scan, 256 position, time duration: roughly 80 minutes
1" fitted velocity and the deconvolution velocity (side by side)
Conlusions and Discussions#
- The deconvolution results are fairly ok to show loops, outflows/downflows (ie. blue/red shifts) for large-scale features, for example, see positions A to H (except F).
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- For small-scale features, the reconstruction is not ok enough to show fine structures, for example, see position F on both images.
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- Due to having only two projections (order_0 & 1 images), the deconvolution is not good enough to reveal small or changed-rapidly structures. But considering 1" scanning usually takes long time to finish (in this case, 80 minutes for a small FOV), it is also not good enough to observe fast-changing features. So it looks the slot deconvolution would be useful for, for example, synoptic velocity review(?)
- A few issues during the deconvolution using this datasets are caused by that the order-0 & 1 images come from different instruments: TRACE & EIS. The following factors are imported:
- CCD pixel size and resolution are different
- Instrument response is different, eg, response fuctions & PSF
- Spectral resolution is different, eg, TRACE covers wider range for FeXII 195 line compared with EIS 195 line (according to drw)
- images from TRACE & EIS may have different distortions and alias, which makes alignment difficulties
The above factors effect the image quality and thus alignment and reconstruction. However, the above factors can be reduced significantly if both order-0 & 1 images come from same instrument.
- The large FOV image is needed as it helps alignment. But the data of EIS 40" slot needs to process to get full FOV image, which effects image quality. So if possible, using wider slot (eg. 266" slot) is better
- If shifts order-plus images a few pixels along X-axis prior to deconvolution procedure, the reconstructed velocity maps will have slightly differences compared with no X shifts result:
Full FOV deconvolution: X shifts are -3, -2, -1, 0, 1, 2, 3 pixels from left to right and top to bottom
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Small FOV deconvolution: X shifts are -3, -2, -1, 0, 1, 2, 3 pixels from left to right and top to bottom
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For your information:
Ignacio Ugarte-Urra: using 40" slot to do plasma diagnostics: electron density and DEM analysis