NotesKeckPSF < Keck/NGAO

---+!! Notes on Keck AO for !PSF Recovery Project

%TOC%


---++ AO Parameters

---++++!! AO Sign Conventions

Keck DM to !WFS geometry:  Square subaperture Hartmann sensor lenslets.  Actuators are located at the corners.  This geometry is sometimes referred to as a "actuator centered Fried Geometry"  [[%ATTACHURL%/][see picture (not posted yet) ]].  Detail on numbering and orientation can be found here [[%ATTACHURL%/KAON368.pdf][KAON 368 ]].  The actuator spacing is 7 mm at the DM corresponding to 0.200 mm at the lenslet array. 562.5 mm at the telescope primary mirror and 74.8 mm on the virtual pupil image formed by the telescope pupil secondary.  The secondary obscuration (including mirror support and baffling) is circular with a diameter of 2.65 m on the center of the primary mirror.       

The following IDL code [[%ATTACHURL%/disp2d.pro][ disp2d.pro]] and associated text files  [[%ATTACHURL%/sub_ap_map.txt][sub_ap_map.txt]] and [[%ATTACHURL%/act_map.txt][ act_map.txt]] are useful for plotting and displaying AO data queried from the telemetry systems (TRS) with the IDL tv command.

---++++!! !WFS 

---++++!! Telemetry TRS
 
The basic method of querying the TRS system using our IDL library is described here [[http://www2.keck.hawaii.edu/optics/ao/ngwfc/trsqueries.html][Keck Telemetry Webpage]] the most important thing on that web page is the description of the SQL tables and the field names.  An example of using the IDL library is [[%ATTACHURL%/gettrs.pro][gettrs.pro]].  This code queries both the full frame rate table (ffb) and the configuration table (configuration).   We have been using variations of this tool to save AO telemetry data in the IDL save file format (*.sav).  These files can be read into IDL with the restore command.  The IDL help and help,/structure command are useful to see what has been saved.  SQL tables names are generally preserved as field names (i.e.offsetcentroids, dmcommand, etc.) of the relevant data structure. 

---++ NIRC2 Parameters

NIRC2 is the main imagining camera used with the Keck 2 AO system. It is positioned behind the AO bench on the Left Nasmyth Platform of Keck II telescope. The instrument operates from 1 to 5 µm, providing three selectable cameras to cover the expected range in image sizes. Two filter wheels with 18 positions each provide a variety of filters and/or grisms, while a focal plane mechanism provides slits and occulting spots for coronography. A dedicated slide carries larger grisms for spectroscopy. Six selectable pupil masks are available to reduce background noise sources; four of these rotate in concert with the telescope pupil and one is specific to spectroscopy.The detector is a 1024x1024 Aladdin-3 InSb array with four-quadrant readout into 32 channels.The main public NIRC2 web page is here: [[http://www2.keck.hawaii.edu/inst/nirc2/][NIRC2 Home Page]] and much useful information is here [[http://www2.keck.hawaii.edu/inst/nirc2/Manual/ObserversManual.html][NIRC2 Observers Manual]]

| Field of view  | 10x10 arcsec (narrow camera) |
|                      | 20x20 arcsec (medium camera)| 
|                      | 40x40 arcsec (wide camera) |
| Pixel scale    | 0.009942 arcsec/pixel (+/- 0.00005) |
|                      | 0.019829 arcsec/pixel |
|                      | 0.039686 arcsec/pixel | 
|  Filters 	       | J, H, K, Ks, Kp, Lp, Ms, H2, Fe II, Br Gam, plus others | 
| Pupil mask    | 1 circular fixed, circumscribes the telescope pupil |
|                      |1 circular rotating, inscribes the telescope pupil and masks the spiders |
|                      | 3 hexagonal, rotating | 

A number of telescope, AO system, and instrument "keywords" that are useful for observers are added to the NIRC2 FITS files as additional header fields.  The ones used by the Flicker PSF estimation code include the following:
   
    | OBJECT     | Object name        |
    | UTC            | Coor. UT (h:m:s) |       
    | DATE-OBS | UT date of obs Year-Month-Day |
    | NAXIS1      | Number of pixels in axis 1  |
    | NAXIS2      | Number of pixels in axis 2  |
    | COADDS    | number of coadds  |
    | SAMPMODE | Sample mode 1=Single; 2=CDS; 3=MCDS | 
    | NREADS      | Number of reads per integration, if SAMPMODE = 3  |  
    | ITIME           | Integration time per coadd          |
    | FILTER        | Composite filter names (both wheels)           |
    | EFFWAVE    | effective wavelength of passband (microns) |
    | MINWAVE    | minimum wavelength of passband (microns) |
    | MAXWAVE   | maximum wavelength of passband (microns) |
    | WSFRRT     | Frame rate for WFS camera (Hz) |
    | CAMNAME  | camera slider's named position, one of:  narrow, medium wide |
    | PMSNAM     | pupil wheel's named position, one of: INCIRCLE, LARGEHEX, MEDIUMHEX, SMALLHEX, OPEN, ...    |
    | PMRANGL  | Pupil mask drive angular position (deg) |     
    | WSFRRT     | Frame rate for WFS camera (Hz) |
    | ROTMODE  | Mode of AO system K-mirror one of, position angle, vertical angle, or stationary |
    | DTCLP        | OPEN/CLOSE Tip Tilt Closed Loop Mirror Positioning | 
    | AODTSTAT  | AO deformable mirror loop state |
    | AODMSTAT | AO deformable mirror loop state |

---++ Telescope Parameters 

---++++!!  Need to add Secondary obstruction, Spiders, Pupil orientation, Segment wavefront maps, and Segment exchange information

The secondary obscuration (including mirror support and baffling) is circular with a diameter of 2.65 m on the center of the primary mirror.       

---++ Links, KAONs, and other References
   * [[http://mkwc.ifa.hawaii.edu/current/seeing/][Mauna Kea MASS DIMM Data Webpage]]
   * NGWFC/RTC Algorithms  [[%ATTACHURL%/517Algorithms.pdf][KAON 517 ]]
   * Centroid, Subaperture, & Actuator Conventions [[%ATTACHURL%/KAON368.pdf][KAON 368 ]]
   * [[http://www2.keck.hawaii.edu/optics/ao/ngwfc/trsqueries.html][Keck Telemetry Webpage]]
   * [[http://www2.keck.hawaii.edu/optics/ao/][Main Keck AO public Webpage]]

-- Main.ChrisNeyman - 20 Aug 2010
Attachments
Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
txt	sub_ap_map.txt	r1	manage	0.8 K	2010-09-16 - 17:55	UnknownUser	Subaperture Mape text file
This topic: Keck/NGAO > WebHome > PSF > NotesKeckPSF
Topic revision: r4 - 2010-09-16 - ChrisNeyman