FWHM_final.png
Resolving_power_final.png
[PIPE2D-465] Estimate resolution of the spectrograph Created: 17/Oct/19 Updated: 18/Oct/19 Due: 18/Oct/19 Resolved: 18/Oct/19 |
|
| Status: | Done |
| Project: | DRP 2-D Pipeline |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Task | Priority: | Normal |
| Reporter: | ncaplar | Assignee: | ncaplar |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Attachments: |
FWHM_final.png
Resolving_power_final.png
|
| Story Points: | 2 |
| Reviewers: | hassan |
| Description |
|
Jim has asked me to estimate FWHM of the spectrograph in low and medium resolution mode. Few wavelengths across the detector would be beneficial. He says that FWHM are good enough, he can then do resolution calculation. This is my understanding, the issue was also discussed on telecons on October 16, so there is possibility I missed something (hassan?). |
| Comments |
| Comment by hassan [ 17/Oct/19 ] |
|
This task was raised during the MNG1 telecon on 2019-10-15 and briefly during the SpS telecon today 2019-10-16. |
| Comment by hassan [ 17/Oct/19 ] |
|
This work is related to checking requirement SPS-REQ-42 of document LAM-PFS-RAO-1001 (https://pfs.ipmu.jp/internal/webdav/tech/SpS/Document_Project_LAM-Mirror/LAM/00_SpSystem/Top-Level_Documents/LAM-PFS-RAO-1001_3.1_FPRD_Signed.pdf) |
| Comment by ncaplar [ 18/Oct/19 ] |
|
Images used for the analysis are, according to their expId. (see https://people.lam.fr/madec.fabrice/pfs/ait_logbook_SM1.html): 1250 (blue, Neon) 1340(low res, red Hgar) 1343(low res, blue HgAr) 1362(mid res, HgAR)
Care was taken to assure that position of the detector is the same for mid-res and red arm of low-res images. I used images dithered by 0.5 pixel. FWHM_final shows the measured FWHM from dithered images. I see no obvious trend with wavelength and the result are consistent with the fixed PSF size, dominated by the influence of fiber (as expected). Resolving_power_final shows deduced resolving power.
To summarize the results in few numbers I quote median FWHM measurements for each setup and the deduced resolving power in the middle of the wavelength range for each setup.
mean FWHM blue: 3.12 +-0.06 pixels
Resolving power blue at 515nm = 2492+-48 Resolving power low-res red at 800nm = 2983+-120 Resolving power mid-res red at 797.5nm = 5398+-180
|