r1_LSF.zip
[REDMINE1D-230] [RM-6104] analyze the cpu time gain vs success rate using loglambda, taking into account the expected LSF of lambda Created: 05/Jul/23 Updated: 05/Jul/23 |
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| Status: | In Progress |
| Project: | 1D Redmine |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Normal |
| Reporter: | Redmine-Jira Migtation | Assignee: | Redmine-Jira Migtation |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
r1_LSF.zip
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| Description |
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Created on 2020-11-06 09:28:38 by Didier Vibert. % Done: 10 F. Madec has computed LSF profiles for various fibers wrt the wavelength and the position of the spectra on the detector-field. First all the LSF seems very close to Gaussian shape. But since the instrument focal field is spherical and the detector is flat there is a radial de-focus leading to an increase of the LSF FWHM when going from the central wavelength to the extremities of the spectra, plus a global increase for the spectra at the border of the field compared to the spectra in the middle of the image. Taking into account this aspect for log-lambda resampling, means selecting a log-lambda step equal, for each spectra, to the better resolving power (smaller delta_lambda/lambda). This can increase by a huge factor the number of sampling points compared to a log-lambda resampling associated to a constant resolving-power. We thus need to re-evaluate the time performance using a log-lambda sampling adapted to the expected resolving-power. |
| Comments |
| Comment by Redmine-Jira Migtation [ 05/Jul/23 ] |
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Comment by Didier Vibert on 2021-01-08 12:53:05: The contribution of the optic before the entrance pupil of the fiber going to the spectrograph is not taken into account, notably the coupling of the fiber, and thus it's entrance aperture which may change the PSF shape and size at the detector plane. In this dataset the entrance aperture is nominal. We can already look at these, and then ask for Blue Camera data and data with non-nominal aperture (test performed by Neven Caplar) |
| Comment by Redmine-Jira Migtation [ 05/Jul/23 ] |
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Comment by Vincent Le Brun on 2021-07-16 12:58:19: |
| Comment by Redmine-Jira Migtation [ 05/Jul/23 ] |
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Comment by Didier Vibert on 2022-08-31 14:03:31: For that, we can examine 3 configurations of amazed:
Of course the answer will also depend on the loglambda sampling step which corresponds to the redshift sampling of the zPDFs. Thus this analysis should be based on spectra with expected intrument LSF, which varies with lambda, and position of spectra in the focal plane. Some tests were already done: cf #5969, #7088, #5994 |