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en:praktikum:sonnenrotation [2016/07/12 12:28] – [Data reduction] rhainich | en:praktikum:sonnenrotation [2023/07/21 21:24] (current) – [Report] rhainich | ||
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====== S1 - Solar Rotation ====== | ====== S1 - Solar Rotation ====== | ||
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The observation will be performed with the solar telescope in the " | The observation will be performed with the solar telescope in the " | ||
+ | ===== Data reduction ===== | ||
++++ Data reduction for data taken before 2016: | | ++++ Data reduction for data taken before 2016: | | ||
- | Login at the [[en: | + | Login at the [[en: |
The TIFF images can be viewed in // | The TIFF images can be viewed in // | ||
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(The default contrast settings are generally unfavorable, | (The default contrast settings are generally unfavorable, | ||
- | We use [[en: | + | We use //[[en: |
* Convert TIFF to FITS | * Convert TIFF to FITS | ||
* Read-in the FITS file | * Read-in the FITS file | ||
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Luckily, the required program ('' | Luckily, the required program ('' | ||
kate konvert.pro & | kate konvert.pro & | ||
- | to open the script and change the parameters that describe the input files (filenames, dimensions). To compile the program, start GDL | + | to open the script and change the parameters that describe the input files (filenames, dimensions). To compile the program, start //GDL// |
gdl | gdl | ||
then compile the program via | then compile the program via | ||
gdl> .compile konvert.pro | gdl> .compile konvert.pro | ||
- | The program itself is started in GDL by calling the program name, which in this case should be | + | The program itself is started in //GDL// by calling the program name, which in this case should be |
gdl> konvert | gdl> konvert | ||
- | The program converts and rotates the images, then saves the FITS files. They can be viewed (outside of GDL) with | + | The program converts and rotates the images, then saves the FITS files. They can be viewed (outside of //GDL//) with |
ds9 filename.fits & | ds9 filename.fits & | ||
The image should be clearer and rotated in comparison to the TIFF file. | The image should be clearer and rotated in comparison to the TIFF file. | ||
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===== Analysis ===== | ===== Analysis ===== | ||
- | The analysis can be done with a Python script (see '' | + | {{section> |
+ | |||
+ | The analysis can be done with a Python script (see '' | ||
Open the script with a text editor, e.g. | Open the script with a text editor, e.g. | ||
+ | |||
kate comparespecs.py | kate comparespecs.py | ||
+ | |||
In the upper part of the script, find " | In the upper part of the script, find " | ||
- | ./comparespecs.py | + | |
- | to obtain a PostScript | + | python |
- | | + | |
+ | to obtain a PDF file spectrum.pdf, which can be opened with //okular// | ||
+ | |||
+ | | ||
This figure should now show the spectrum of the lines previously selected from the image. From this figure the Doppler shift of the spectral lines can be determined. To do this, the best strategy is to shift the spectra (with the help of the Python script) against each other, so that (1) the solar iron lines are superimposed and (2) the telluric oxygen lines are superimposed. The dispersion ('' | This figure should now show the spectrum of the lines previously selected from the image. From this figure the Doppler shift of the spectral lines can be determined. To do this, the best strategy is to shift the spectra (with the help of the Python script) against each other, so that (1) the solar iron lines are superimposed and (2) the telluric oxygen lines are superimposed. The dispersion ('' | ||
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*/ | */ | ||
+ | |< 50% - >| | ||
^ | ^ | ||
| Fe | 630.151 | | Fe | 630.151 | ||
| Fe | 630.250 | | Fe | 630.250 | ||
+ | | O< | ||
+ | | O< | ||
| O< | | O< | ||
| O< | | O< | ||
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Using the Doppler shift one can determine the rotational velocity of the sun and from that its rotational period. **Note, that the observation has not necessarily been performed at the sun's equator.** | Using the Doppler shift one can determine the rotational velocity of the sun and from that its rotational period. **Note, that the observation has not necessarily been performed at the sun's equator.** | ||
- | ===== Protocol | + | ===== Report |
- | //A usual protocol | + | //A usual report |
- | The protocol | + | /* |
+ | **OLD BELOW** | ||
+ | |||
+ | The report | ||
+ | */ | ||
[[en: | [[en: | ||