Shane AO  

Procedure: Seeing, Freid (r₀) parameter and Transmission estimates

Introduction

Data Acquisition

Telemetry Analysis

Seeing Analysis

Record Parameters

DIMM (Deprecated September 2021)

Notes

Modification Record

Introduction

Data Acquisition, seeing-logging; data()

1. V=6.5-7.5: Acquire V=6.5-7.5 magnitude^{Note 1}, isolated star near zenith. Must not saturate ShARCS or guide camera. Typically, useful isolated sources have HD or BD identifiers.

   SIMBAD basic query

2. Guide camera: Focus star; Estimate prevailing seeing.
3. Isolated, point source verfication (ShaneAO - tt peeko GUI).
4. COG: Set center-of-gravity (COG) centroiding. (WFS centroider: GOG; Refcents file: corresponding to COG).
   Alternatively: cent('cog')
5. WFS camera dark; TT camera dark: Acquire backgrounds (Offset telescope, WFS camera dark, TT camera dark, Back to target).
6. Close WFS loop (ShaneAO loop control GUI). Verify functionality/stability/offloading.
7. -0.5 < foc < + 3.0 (ShaneAO - peeko GUI).
8. Open loops (in ShaneAO loop control GUI).
9. Update boresight indicator, if necessary.
10. seeing-logging^{Note 2}: Execute the following command, responding to prompts where appropriate:

    user@shimmy.ucolick.org:/u/user/observers/lgs/saocon_setups/seeing-logging.sh

11. Telemetry data: Acquire at least one (Open loops) data set:
    • Actions... Save telemetry data (ShaneAO loop control GUI).
      Alternatively: data()
    • File produced should be of the form:

      /data/telemetry/YYYY-MM-DD/Data_XXXX.fits

      (e.g: /data/telemetry/20XX-XX-XX/Data_0003.fits)

Telemetry Analysis, ta

Function:

Prerequisites:

Execution:

1. Connect to appropriate host machine:

   ssh -l user -X karnak.ucolick.org

2. Activate Python environment:

   conda activate shaneao

3. Execute telemetry analysis (ta) command, e.g:

   ta -n 2,3 -p -s 'HD 172243' -d 2021-09-22

   where,

   -n 2,3 specifies the identity(ies) of the (open loop) telemetry file(s) to be analysed.

   -p specifies that a plot should be displayed.

   -s 'HD XXXXXX' (explicit single quotation marks) specifies the source corresponding to the data (as identified in SIMBAD database). This information is used for calculating transmisson estimates, T.

   -d YYYY-MM-DD specifies the acquisition date of the files to be analysed.

4. To exit, select close from plot window frame pull-down menu.

Characteristics:

Example Output:

 
    
   Data_0002 16x 250.0 Hz COG open 
   r0 = 10.1 cm 
   v = 10.76 m / s 
   f0 = 5.192 Hz 
   Sn = 157.5 nm2 / Hz 
   p = 2.5 
   q = 0.4327 
   star = HD 172243 
   T = 15.9 % 
    
   Data_0003 16x 250.0 Hz COG open 
   r0 = 11.33 cm 
   v = 10.71 m / s 
   f0 = 5.364 Hz 
   Sn = 132.0 nm2 / Hz 
   p = 2.5 
   q = 0.4738 
   star = HD 172243 
   T = 16.4 % 
   

• Preliminary (2021-09-XX) Freid paramater thresholds: NGS > 6 cm; LGS > 9 cm.
• Preliminary (2021-09-XX) transmission values: 10 - 12 %.
• Expect small peak at circa 200 Hz (due operating frequency of mirror).
• For more information, execute following command: ta -h

Seeing Analysis, sa

Function:

Prerequisites:

Execution:

1. Connect to appropriate host machine:

   ssh -l user -X karnak.ucolick.org

2. Activate Python environment:

   conda activate shaneao

3. Execute seeing analysis (sa) command, e.g.:

   sa -p -d 2021-09-22

   where,

   -p specifies that a plot should be displayed.

   -d YYYY-MM-DD specifies the acquisition date of the files to be analysed.

4. To exit, select close from plot window frame pull-down menu.

Characteristics:

Example Output:

 
   -------- Seeing 2021-09-22 -------- 
   average FWHM: 1.21 arcsec 
   average r0: 8.72 cm 
   --------------------------------- 
   

• Excludes semi-static components (therefore a more faithful representation of Freid parameter, r₀.)
• Reports average values.
• For more information, execute following command: sa -h

Function:

Prerequisites:

Execution:

• Open terminal window and connect to real as gavel:

  ssh -l gavel -X real.ucolick.org

• At prompt, execute the following command:

  dimm N

  where N is the integer number of the file produced previously by saving telemetry data. (The dimm dimm /data/telemetry/YYYY-MM-DD/Data_XXXX.fits, filling in the appropriate date and Data file number).

• dimm takes a while to run, but when done, example output is:

   
     mean seeing (l) is 0.65 arcsec 
     mean seeing (t) is 0.77 arcsec 
     

Characteristics:

 
   gavel@real > dimm -h 
    
   dimm [-h --help | -d date ] filenum 
    
   Use DIMM analysis to produce a histogram of possible seeing FWHM 
   given an open-loop data telemetry file (result from a ShaneAO 'data()' command) 
    
   Arguments: 
   -h, --help: print help 
   -d date: set the date of the desired file directory using the format 
   YYYY-MM-DD. Default is today's date 
   filenum: an integer. Data files are named Data_xxxx.fits where xxxx is 
   the file number. You don't need the leading 0s. 
    
   Examples: 
   dimm 2                <- evaluate file Data_0002.fits in the present night's directory 
   dimm 0002             <- leading zeros are ok 
   dimm -d 2015-06-29 2  <- evaluate file Data_0002.fits in June 29, 2015 directory 
   dimm -d 6-29 2        <- present year is implied 
   dimm -d 29 2          <- present year and month is implied 
   dimm /local/data/telemetry/2015-06-30/Data_0002.fits <- evaluate a specific file 
    
   Outputs: 
   "l" (longitudinal) and "t" (transverse) are two different ways of measuring the 
   Hartmann dot differential image motion. On-sky, we find they usually give slightly 
   different answers for seeing estimate. 
   

Recording:

• Date
• Prevailing seeing estimate
• Frame identifiers of guider images
• ShaneAO telemetry data files.
• Frame identifiers, Exposure times and Filter of ShARCS images.

 
   2015 Jan 29: 
   seeing ~1.5” 
   Guider: seeing_2015-01-29_ 100 to 114 
   2015-01-29/Data_0000.fits 
   TT_Data 0 to 29 
   sharcs #232 3s BrG 
   TT_Data 30 to 59 
   sharcs #233 3s BrG 
   

Notes:

Note 1:

Originally, the recommended magnitude was circa V=8.5. However, 2016 discussions with D. Gavel yielded recommendation for brighter stars.

Note 2:

The seeing-logging script has pauses to accommodate configuration and progress checks. Respond to prompts where appropriate. The script writes a log file and copies the appropriate files to a single directory. The data are copied to:

shimmy:/data/lgs_tmp/

and into a date-stamped sub-directory, of the form:

20XX-XX-XX.

Modification Record:

2025-08-06:

Migrated Parameter Recording to Google form.

2022-08-14:

Updated.

2021-09-21:

Updated (dimm deprecated; ta, sa introduced).

2017-06-12:

Updated (shimmy replaced shred).

2016-12-15:

Updated (re-order).

2016-09-15:

Updated (shred replaces shard).

2015-01-31:

Updated.

2014-10-01:

First version.