revised 13/6/01

What is NAOMI?
See also Chris Benn's (not available yet) Observing Recipe


After setting Nasmyth Turret to GHRIL, type: Followed by the normal zerosets, met info and cal last

TCS: DRAMA communications are required...

...for INGRID headers and dithering. Best is to exit the TCS session if one is running and to start up new with DRAMA communications. Log on to LPAS4, choose OPTIONS, then COMMS, then DRAMA. Then return to MAIN and choose START to start both the TCS and TELD drama task.

Alternatively, without exiting the TCS session, you can enter the TCS command "COMMS DRAMA" and then start the TELD task separately (log in to LPAS4, choose OPTIONS and then TELD).

Test Drama communications by sending SYS> cmd TCS USER PAGE
and make sure that the Infodisp page changes. If it doesn't work, enter "COMMS DECNET", then "COMMS DRAMA" and test again.

This method of switching may cause an error message on the navis screen.

AUTOGUIDER: Switch in the computer room - turn to 'NAOMI'

The Naomi Autoguider is sourced from an RS232 line from the Navis computer in the control room. A Rs232 Switch box has been used to switch between normal and Naomi autoguiding. The switch box is in the computer room above LPAS4 which is above the CAMAC crate.

Guiding packets come from the AO loop, specifically from drift found in the Fast Steering Mirror (FSM), which takes out pupil motion (also called  Tip-Tilt) .Since there is no guiding when the AO loop is open, you don't need to turn AUTOGUIDE OFF, even when re-acquiring (unless AO loop has crashed).

The guide star can be the target itself ("self-referencing"), if the latter is sufficiently bright and sufficiently pointlike (< 1.5 arcsec, say, to be smaller than the sub-aperture guide boxes on the wavefront sensor). The guide star cannot be brighter than V = 4, or K ~ 5, because of saturation of the wavefront sensor or science detector respectively. There should be no stars of similar magnitude within ~ 5 arcsec of the guide star, to avoid confusing the wavefront sensor.

Telescope focus 98.60 (Feb 2011):
Measured on the acquisition TV, then subtract a fixed value. 
Alternatively, a change of focus expands/contracts the Shack-Hartmann spot pattern, which should fit exactly into the WFS grid.

Determine rotator center:
Not done by TO. A pickoff mirror inside NAOMI can be accurately positioned at the optical rotation axis of the Nasmyth focus.

Calibrate procedure:
Normal - on the acquisition TV.  A good pointing model will give good tracking, which always helps.


with INGRID (June 2001) On Taurus, enter

>startobssys     choosing correct option for INGRID+NAOMI (+ISIS+...)

This spawns all the necessary command windows, mimics and applications. The main novelties are the commands "dither", "loop open/close" and "rmode".

Dithering is carried out using Craige Bevil's application ("dither"), carrying out a run at different telescope positions. The script opens the AO loop before moving the telescope, and it also moves the AO "pickoff" mirror (a probe in NAOMI focal plane, which feeds to the WFS) in the opposite direction, so that the AO guide star is picked up again. The loop then closes and exposure at the new position begins.

INGRID has a special observing mode especially for use with NAOMI, and is indicated in the row labelled "cds" in the Detector window for INGRID. This allows you to set up the number of exposures to add together (co-add) e.g. "rmode cds 1 60" sets it up to do 60 sec co-added exposures, reading into one frame, so that run 30 would now make 60 x 30 second exposures and co-add them into one frame. The idea of co-adding is to allow deep exposures without saturating bright objects.

with OASIS (in October 2001, pending NAOMI passing tests and schedule)
OASIS is an "integral field" spectrograph (e.g. like Sauron) that works best when the input image is less than about 0.35" wide. You then get sharp image data with spectral information at each pixel.


Observing with the AO guide star off-axis

The WFS assembly includes a "pick-off" mirror (a probe) that allows the AO guide star to be followed by the WFS off-axis, while the science taget is in the centre of the INGRID field.

Set the pick-off X and Y positions to the center and acquire the target onto the WFS display as described above. When the star is centered, then move the telescope by about 1 arsec in the direction towards the science target, noting how much you have to move the pick-off to ce-center the star, and in which direction. You are now ready to make the full offset.

Following the offset, use MARK to store the current telescope position, then gocat to there. You are now ready to use the usual dither command.

In the future there will be a s/w procedure to do all this - promise!

Sky subtraction with INGRID

For deep INGRID exposures, use dithering (see above). However, with extended objects, we also need to take a diterhed sky exposure. Generally offset by 100 or 200 arcsec offset using the Handset, but remember to move in a different direction for each sky exposure, to avoid always looking at a patch of sky with stars. e.g. (1st time) 100 in +X , (2nd) 100 in -X, (3rd) 100 in +Y, (4th) 100 in -Y, (5th) 100 in both, etc., etc.


otherwise you will mess up the Deformable Mirror (DM), which is a bit delicate! The loop can be opened and closed manually at the TopGui control or using "loop open/close" command on taurus.

LN2: INGRID needs to be filled in the middle of the night whenever NAOMI is on, because it's run without the cooler, to avoid vibrations.

NAOMI Observing "modes"

NAOMI has 3 different Shack-Hartmann lenslet arrays, the choice depending on the seeing. The "good seeing array" and "poor seeing array" both have 10x10 lenslets, but the latter have much shorter focal length, so that they produce less spot movement. This should be used iif natural seeing is > 1.2 arsec approx. There is also a 4x4 lenslet array for "even worse" seeing.

Additionally, the WFS can be read out with 3 different binning arrangements: "full frame" (6x6), 4x4 and "quad-cell" (2x2), these numbers referring to the pixels assigned to each Hartmann spot. Increased binning allows you to increase signal-to-noise on fainter stars AND to read out faster (which should help with poorer seeing, but in NAOMI, has not yet been proved to do so...).

Each combination of lenslet array and binning is referred to (by NAOMI designers) as a "mode".

The most important ones are modes 1 and 2, while mode 8 was also tested (didn't work). Mode 1 corrresponds to ["good seeing" lenslets + full frame readout] and mode 2 is ["poor seeing" lenslets + full frame readout"]. Mode 8 is [4x4 lenslets + quad cell readout].

NAOMI Optical Optimisation:

The shape of the Deformable Mirror (DM) and the response of the Wavefront Sensor (WFS) are optimised using this procedure (see Frank Gribbin's notes for more detail): Now ready to be adaptive!

Transfer of TCS control to/from Naomi workstation

1) Start TCS as normal 

2) On navis authorize display from TCS Alpha 

      xhost +lpas4 

   Then set up key definition (for <-INC).  
      xmodmap -e "keysym F19 = Find" 

3) From lpas4 create a second TCS information display 

      USER> CLONE ON navis 

   A slave copy of TCS information display should appear on navis
   in around 20 seconds. This display can be left running until 
   TCS is shut down or can close later with CLONE OFF navis   

4) Transfer control of TCS to navis 

     USER> TRANSFER ON navis 

   A terminal is created on Navis, with TCS user prompt. Takes about 
   20 seconds. In the TO's window a message says control has been

5) Transfer control back to TCS 

   On navis : 


   Control returns to TO window. There's no need to close the 
   window on navis. This takes about 2 seconds. Subsequently 
   control can be switched back and forth using steps 4 and 5. 

   In emergency TO can grab back control by using control-Z

6) Use of TCS HANDSET from navis 

   The key definitions on Navis are different 

   TO key     Navis key    Function  

   HANDSET    COPY         Enters/Exits HANDSET mode 
   INC->      INSERT       Select larger increments       
   <-INC      FIND         Select smaller increments 
   ALT/AZ     none         Not available 
   RA/DEC     F7           RA/DEC mode 
   XY         F8           X/Y mode 
   OFFSET     F9           Offset mode 
   APOFF      F10          Aperture offset mode  
   FOCUS      PROPS        Adjust focus 
   ROTATOR    UNDO         Adjust Rotator 
   OWN        None         User entered increments not available    

   Arrows     Arrows       Input increments (move by selected 

Notes : 
i)  In case names do not work, ip addresses can be used        
ii) Don't resize TCS USER window, as HANDSET display may not work 

                                        Frank Gribbin 
                                        Version 1