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| Smiling spectra (curved) https://forum.vdsastro.de/viewtopic.php?t=4112 |
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| Autor: | Filipe Dias [ 06. Februar 2014, 19:04:20 PM ] |
| Betreff des Beitrags: | Smiling spectra (curved) |
The "L" in "LHiRes" stands for "long-slit", and I love that letter just as much as the the other 5 letters put together ("Hi-Res"), in the name for this spectrograph!.. However, while trying to take full advantage of the "long slit" I meet the known curved shape of spectral lines.. IRIS has a command ("smile") that corrects for a constant curvature present on the 2D spectrum. But, I have noticed that this "smile" actually varies a bit with wavelength. This is annoying when subtracting the sky background, because it won't match along the 2D spectrum. Since the background signal is being sampled too far away from the center of the slit, it increases the problem. I would like a way to interpolate the smile correction, even if only linearly.. I could estimate smile on the red side, and on the blue side, and interpolate that in between.. Would I need to use MIDAS for this? I can also divide my spectrum into wavelength-portions, and treat each portion with a different smile.. More work, but it could work... |
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| Autor: | Christian Netzel [ 06. Februar 2014, 22:38:49 PM ] |
| Betreff des Beitrags: | |
Hello Filipe, Iras considers automatically the curvature of the lines of a calibration spectrum as well as the curvature of the image of the slit. To my knowledge even midas has not the ability to account for the last one. This feature is important because it improves in many cases the S/N. Cheers Christian |
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| Autor: | Daniel Sablowski [ 11. Februar 2014, 15:52:01 PM ] |
| Betreff des Beitrags: | |
Hey Filipe, I thought L stands for Littrow... |
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