Differences between revisions 24 and 54 (spanning 30 versions)
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=== NP, June 1st, 2012 === Create one page per subject, but keep all updates and new entries for the same subject in the same page, otherwise discussions are too difficult to follow (e.g. below: subject Gaussian beam and Disk Planet, has 3 entries).
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Thanks to Robert's and Samuel's verifications, I found a bug in my simulation (the disk diameter was actually taken as the radius, hence doubling the effective size of the disk and enlarging the broadening). I remove the old plot of May 29 to avoid confusion and provide updated plots here below. - [[XFocNikaRun4|Cross and focus analysis]] FXD, Sept 4, 2012
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The following plot shows the result of the convolution of a Gaussian (FWHM=10 arcsec) by a Gaussian (FWHM=8arcsec) or a disk (D=8arcsec). The gaussian indeed leads to a large broadening compared to the disk. Fitting an effective gaussian on the result of disk convolution leads to a slight overestimation of the input 10 arcsec. - [[FocusOffBtw1and2mm | Focus offset between 1 and 2mm arrays, RZ, August 8, 2012]]
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{{attachment:disk_convol_D=8_max_frac=0.1.png||width=400}} - [[BadTelescopeTracking | No way to determine the synchro. btw NIKA & telescope, RZ, July 18, 2012]]
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If we proceed with the same exercise but with a 20arcsec gaussian or disk, this time the difference between the convolution by a disk or a gaussian becomes significant. An effective gaussian can still be fit, but only around the peak (crosses highlight the points on which the fit is performed). - [[Zigzag | No need for further Zigzag correction, NP, June 22nd, 2012]]
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{{attachment:disk_convol_D=20_max_frac=0.7.png||width=400}}
{{attachment:disk_convol_D=20_max_frac=0.1.png||width=400}}
- [[InRunProc |Plateau, beams, glitches, and synchronization displayed by RZ (and others ?) during the run in the daily reports, gatered here in a more readable presentation, June 15st, 2012, SL]] (now the [[DailyRepots| Daily Reports]] contain only pictures and plots from cryogenics besides the daily descriptions so that the page loading time is improved).
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Finally, we propose a chart of this effect for various beam FWHM and planet disk diameters: - Data products: 12 June 2012: on the neel share area: /Archeops/NikaRun4AllData/FitsData you will find the Raw data (Z_ files) and fits files (A_ and B_). Imbfits files are on iram.es computers (to be reprocessed). Pixels directory gives the focal plane geometry reconstruction in fits files (Scan #218 on the 4h is recommended).
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{{attachment:fwhm_planet_2.png||width=600}} - [[ZemaxSimul2012 |Zemax simulations: FOV geometry simulated with grid distortion, effect of focus on PSF: June 04, 2012, SL]]
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=== RZ, May 30 2012 === - [[PlanetConvol |Gaussian beam and Disk Planet: May 29, 2012, NP; May 31, 2012, RZ; June 1st, 2012, NP]]
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The figure fwhm_planet.png gives effective FWHM ~16 and 20arcsec for an 8arcsec disk convolved with 10 and 17arcsec Gaussians (input FWHM) correspondingly. This cannot be correct ! The upper limits for the resulting FWHM can be calculated for a convolution of a Gaussian with FWHM=8arcsec instead a disk: sqrt(8^2^+10^2^)=12.8 and sqrt(8^2^+17^2^)=18.8arcsec. To get the correct numbers I calculated the 2 cases, i.e. convolved an 8arcsec disc with FWHM=10 and 17arcsec Gaussians. The resulting sources are very well represented by Gaussians with FWHM of 11.1 and 17.7arcsec (no restrictions for the fitting). The difference of the resulting sources and the Gaussian fits are presented below. The discrepancy is -0.4 to +0.14% for the convolution with a FWHM=10arcsec and much below 1% for the convolution with a FWHM=17arcsec Gaussian. The effective FWHM in figure fwhm_planet.png therefore do not represent the correct values - or do I have a problem in reading this figure ?

{{attachment:disk8convGauss10-gFit.png}}
{{attachment:disk8convGauss17-gFit_large.png}}
 
=== NP, May 29 2012 ===

[[PlanetConvol | Gaussian beam and Disk Planet, May 29, 2012, NP]]
- (([[attachment:NikaRun4/RZearlyResults.pdf|RZ early results, posted by FXD]])). Same thing but with logbook information and a comment to understand the scans, their relations to each other and the context: [[attachment:Mars_beams_central_pix_from_RZearlyResults.pdf|Mars beams on central pixel, effects of atmosphere, focus and tests to investigate the plateau, SL June 13 2012]] using plots from RZ early results (which were not posted by RZ...). Note the focus drift during the plateau tests which we missed and twisted the results of the tests.

Back to the NIKA run 4

Offline Processing Results

Create one page per subject, but keep all updates and new entries for the same subject in the same page, otherwise discussions are too difficult to follow (e.g. below: subject Gaussian beam and Disk Planet, has 3 entries).

- Cross and focus analysis FXD, Sept 4, 2012

- Focus offset between 1 and 2mm arrays, RZ, August 8, 2012

- No way to determine the synchro. btw NIKA & telescope, RZ, July 18, 2012

- No need for further Zigzag correction, NP, June 22nd, 2012

- Plateau, beams, glitches, and synchronization displayed by RZ (and others ?) during the run in the daily reports, gatered here in a more readable presentation, June 15st, 2012, SL (now the Daily Reports contain only pictures and plots from cryogenics besides the daily descriptions so that the page loading time is improved).

- Data products: 12 June 2012: on the neel share area: /Archeops/NikaRun4AllData/FitsData you will find the Raw data (Z_ files) and fits files (A_ and B_). Imbfits files are on iram.es computers (to be reprocessed). Pixels directory gives the focal plane geometry reconstruction in fits files (Scan #218 on the 4h is recommended).

- Zemax simulations: FOV geometry simulated with grid distortion, effect of focus on PSF: June 04, 2012, SL

- Gaussian beam and Disk Planet: May 29, 2012, NP; May 31, 2012, RZ; June 1st, 2012, NP

- ((RZ early results, posted by FXD)). Same thing but with logbook information and a comment to understand the scans, their relations to each other and the context: Mars beams on central pixel, effects of atmosphere, focus and tests to investigate the plateau, SL June 13 2012 using plots from RZ early results (which were not posted by RZ...). Note the focus drift during the plateau tests which we missed and twisted the results of the tests.

OffProcNika4 (last edited 2012-10-01 14:22:21 by NikaBolometer)