Starting exposures and shuffle options
[Nod+Shuffle][Shuffle-arc][2-shuffle][3-shuffle][N-shuffle][2-straddle-shuffle][3-straddle-shuffle]

NOTE:  The available field of view depends on the shuffle mode being used. Nod+Shuffle and 2-shuffle allow the two circular 10' fields to be stored simultaneously on the CCD. A general N-shuffle reduces the field - in the vertical direction only - by a factor 3/(2N-1) and requires an aperture mask matched to the operation. For example, the 3-shuffle mode produces three rectangular images, each of which covers a field of view 10' x 6'.
 

Simple exposures

Simple exposures are initiated from the CCD window, e.g. (type help for more details)

          glance <exp>
          run <exp>

These are good for calibrations...

          bias
          sflat
          dflat

Run sequences

Here are explicit in-line commands you can use via the TAURUS control window if you feel confident with the system. If you are in shuffle mode (see prompt on CCD window), you will need to type method default first. Hit "." on the TAURUS window keypad, and after the ":" prompt, type

          ccd_runstep  0 10 790

These are usefui in-line commands for sausage cubes.....the following is particularly elegant for flux standards or flats at the end of the night....

          ccd_runfile  n253.flats

                        Example:

                                ! This is a legal comment line
                                ! You can have z values listed like
                                100 110 120 130 140 150

                             ! or even as ....
                                101
                                231
                                143
                                98
                                -405
 

For shuffles to work correctly, you need to have started up TAURUS-2 with the CCD_SHUFFLE option.  Be aware that these modes will be much easier to activate once we have full automatic control of the CS100 TTF contorller, but this won't be ready until late 1999.

Nod+Shuffle imaging spectroscopy

This method is used for VPH spectroscopy, diffuse detection or with the TTF when set to a fixed z value. You cannot currently do changes in z in combination with nod+shuffle since both actions use the instrument sequencer. This is actually easy enough to fix if we ever get around to it.

So here are the full details on how to bring up nod+shuffle with TAURUS. Bring up all the VAX windows on the main screen. The shuffle file making facility will need to be run under unix.  I have stored the passwords for NIGHT and OBSERVER under unix elsewhere, so do ask ahead of time.
 

Shuffle arc (Long-slit spectrum)

The most commonly used option for calibrations is the 80-shuffle long-slit spectrum. Set the correct filter, slit mask and CCD window using the SMS window. Alternatively, here are explicit in-line commands you can use via the TAURUS control window if you feel confident with the system. Hit "." on the TAURUS window keypad, and after the ":" prompt, type

In the SMS control window, click on run / run_ccd / shuf_multi which brings up theshuffle window. Ensure the following parameters are set.

CCD charge shuffling multi line
Csr_Default disk$user:[observer.cs_files]*.csx
Csr_Filename eighty
Preexpose_info 3_1000_100
Cycle_count 1
Bias True     False
Setup_Array True     False
Etalon_Start 0
Etalon_Increment 7
We set this running with PF1.

And this is sort of what you should see, bias strip and all (it's actually CuAr observed through the R1 filter).

If you are at all unsure of shuffling, you can return to standard CCD exposures, or run_step exposures, after typing "method default" at the CCD window.
 
 
 

Two shuffle

Set the correct filter, slit mask and CCD window using the SMS window. Alternatively, here are explicit commands you can use via the TAURUS control window if you feel confident with the system. Hit "." on the TAURUS window keypad, and after the ":" prompt, type

In the SMS control window, click on run / run_ccd / shuf_multi which brings up theshuffle window. Ensure the following parameters are set.

CCD charge shuffling multi line
Csr_Default disk$user:[observer.cs_files]*.csx
Csr_Filename twostep60m
Preexpose_info 3_1000_100
Cycle_count 10
Bias True     False
Setup_Array True     False
Etalon_Start 68
Etalon_Increment 30
We set this running with PF1.

The file twostep60m.csx is explicitly for 2-shuffles, with a minute at each band. Here we have requested 10 cycles, therefore the total exposure time is (a little more than) 20 minutes. There exists a few other twostep files called twostep3m, twostep10m, twostep30m.  The OH power spectrum has no preferred timescale so I would recommend sticking with 1 minute per band.  Note that the plates are to be switched between Z_s = 68 and Z_s = 98.
 
 
 

Three shuffle

Set the correct filter, slit mask and CCD window using the SMS window. Alternatively, here are explicit commands you can use via the TAURUS control window if you feel confident with the system. Hit "." on the TAURUS window keypad, and after the ":" prompt, type

In the SMS control window, click on run / run_ccd / shuf_multi which brings up theshuffle window. Ensure the following parameters are set.

CCD charge shuffling multi line
Csr_Default disk$user:[observer.cs_files]*.csx
Csr_Filename threestep60m
Preexpose_info 3_1000_100
Cycle_count 5
Bias True     False
Setup_Array True     False
Etalon_Start 68
Etalon_Increment 30
We set this running with PF1.

The file threestep60m.csx is explicitly for 3-shuffles, with a minute at each band. Here we have requested 5 cycles, therefore the total exposure time is (a little more than) 15 minutes. There exists a few other threestep files called threestep3m, threestep10m, threestep30m.  The OH power spectrum has no preferred timescale so I would recommend sticking with 1 minute per band. Note that the plates are to be switched between Z_s = 68, Z_s = 98 and Z_s = 128.

If you need to switch between unevenly spaced settings, we need to do two things. First, we load up Z-values into the Z-array in the SMS  control window. Go to sel_fil_z_array and define the first three entries with your chosen values. Or you can do this explicity from the SMS key pad after "." using

obeyw taurus sfill  1  23
obeyw taurus sfill  2  195
obeyw taurus sfill  3  49
Second, change "Setup_Array" to false which means that "Etalon_Start" and "Etalon_Increment" are ignored.

CCD charge shuffling multi line
Csr_Default disk$user:[observer.cs_files]*.csx
Csr_Filename threestep60m
Preexpose_info 3_1000_100
Cycle_count 5
Bias True     False
Setup_Array True   False
Etalon_Start 68
Etalon_Increment 30
We set this running with PF1.
 
 

N-shuffle
(in progress: generalize "Three shuffle" which means making a specialized mask and CCD window. For shuffling on N arbitrary numbers, use perl script below or define through sel_fil_z_array.)
 
 

2-straddle shuffle

The straddles are the most sophisticated of the shuffle options. These are a bit clunky to set up under the current SMS control system.  Set the correct filter, slit mask and CCD window in the normal way. Alternatively, here are explicit commands you can use via the TAURUS control window if you feel confident with the system. Hit "." on the TAURUS window keypad, and after the ":" prompt, type

In the SMS control window, click on run / run_ccd / shuf_multi which brings up the shuffle window. Ensure the following parameters are set.

CCD charge shuffling multi line
Csr_Default disk$user:[observer.cs_files]*.csx
Csr_Filename straddle60m
Preexpose_info 3_1000_100
Cycle_count <integer: see below>
Bias True     False
Setup_Array True   False
Etalon_Start 0
Etalon_Increment 7
We set this running with PF1. But before you do that, a little explanation is required........

Setting "Setup_Array" to false means that "Etalon_Start" and "Etalon_Increment" are ignored. Instead, we need to fill the Z-array look-up table explicitly. Take a look at the file disk$user:[observer.icl_load]n253.icl. This is full of ICL commands:

obeyw taurus sfill 1 52
obeyw taurus sfill 2 38
obeyw taurus sfill 3 52
obeyw taurus sfill 4 76
obeyw taurus sfill 5 52
                :
                :
obeyw taurus sfill 40 76
This fills the Z-array with 40 values in the order shown. "52" is the on-band, "38" is the blue off-band and "76" is the red off-band. Now, the number of cycles <integer> associated with n253.icl is the number 10 since straddle60mcontains four actions for every cycle. Since straddle60mis hard-wired for a 60 sec exposure per Z-step, each cycle corresponds to 4 mins. The file "n253.icl" is for a total exposure of 40 mins where a single cycle steps through "52 38 52 76" generating a double image on the screen. The on-band is a total exposure of 20 mins at Z=52; the off-band is an averaged exposure of 20 mins at Z=38 and Z=76.

By the way, if you decide to shuffle through fewer than 10 cycles, say for a flux standard, that's fine since the remaining Z values are just ignored. In fact, if you want, since there are 255 entries in the Z-array, you might as well generate a file with 200 entries, i.e. 50 repetitions of the "52 38 52 76" sequence. This is helpful in the event that you want to increase the number of straddle cycles, or a larger value is typed in error. Don't attempt to fill all 255 slots of the Instrument Sequencer memory as this will hang the machine.



So how do we quickly generate the straddle files and how do we load up into the Z-array in the SMS  control window.

Step 1:   First, download this perl script to your local directory and type "chmod +x shuffle_cycle.pl" to make it executable. You only need to do this once, obviously.  Let's generate the example file. Under unix, type

shuffle_cycle 52 38 52 76  >   n253.icl
This operation will be easier under the new system. It is an advanced shuffle option as I have said many times. You will benefit from the observations which is the important point.

Step 2:   We must now transfer the file using FTP for two reasons: (i) it needs to be sent as ASCII - a simple "mv" under unix is not enough, (ii) the /vaxuser/observer area is read only. Download this shell script  and type "FTPtoVAX n253.icl password". It will prompt you for the password. You can check to see that your file arrived ok with "ls -tl /vaxuser/observer/icl_load."

Step 3:   You are almost there. Now go to the TAURUS control window and type "." on the keypad. When you get the ":" prompt, type

load disk$user:[observer.icl_load]n253
and the Z-array is now filled with "52 38 52 76 52 38 .....76". You are now ready to initiate the straddle shuffle with PF1. . . . . .


3-straddle shuffle

The straddles are the most sophisticated of the shuffle options. These are a bit clunky to set up under the current SMS control system.  Set the correct filter, slit mask and CCD window in the normal way. Alternatively, here are explicit commands you can use via the TAURUS control window if you feel confident with the system. Hit "." on the TAURUS window keypad, and after the ":" prompt, type

In the SMS control window, click on run / run_ccd / shuf_multi which brings up the shuffle window. Ensure the following parameters are set.

CCD charge shuffling multi line
Csr_Default disk$user:[observer.cs_files]*.csx
Csr_Filename 3straddle60m
Preexpose_info 3_1000_100
Cycle_count <integer: see below>
Bias True     False
Setup_Array True   False
Etalon_Start 0
Etalon_Increment 7
We set this running with PF1. But before you do that, a little explanation is required........

Setting "Setup_Array" to false means that "Etalon_Start" and "Etalon_Increment" are ignored. Instead, we need to fill the Z-array look-up table explicitly.  Take a look at the file disk$user:[observer.icl_load]zw3146.icl. This is full of ICL commands:

obeyw taurus sfill 1 350
obeyw taurus sfill 2 298
obeyw taurus sfill 3 376
obeyw taurus sfill 4 350
obeyw taurus sfill 5 435
obeyw taurus sfill 6 376
obeyw taurus sfill 7 350
               :
               :
obeyw taurus sfill 60 376
This fills the Z-array with 60 values in the order shown. "350" is the first on-band,  "376" is the second on-band, "298" is the blue off-band and "435" is the red off-band. Now, the number of cycles <integer> associated with zw3146.icl is the number 10 since 3straddle60m contains six actions for every cycle. Since3straddle60m is hard-wired for a 30 sec exposure per Z-step, each cycle corresponds to 3 mins. The file zw3146.icl is for a total exposure of 30 mins where a single cycle steps through "250 298 376 350 435 376" generating a triple image on the screen. The first on-band is a total exposure of 10 mins at Z=350; the second on-band is an exposure of 10 mins at Z=376; the off-band is an averaged exposure of 10 mins at Z=298,435. (This method was used to great effect by SLL in Apr 00).

By the way, if you decide to shuffle through fewer than 10 cycles, say for a flux standard, that's fine since the remaining Z values are just ignored. In fact, if you want, since there are 255 entries in the Z-array, you might as well generate a file with 200 entries, i.e. 33 repetitions of the "250 298 376 350 435 376" sequence. This is helpful in the event that you want to increase the number of straddle cycles, or a larger value is typed in error. Don't attempt to fill all 255 slots of the the Instrument Sequencer memory as this will hang the machine.

To generate the straddle ICL files, and to initiate the sequence, see above.
 
 
 



If you are at all unsure of shuffling, you can return to standard CCD exposures, run_step exposures, etc. after typing "method default" at the CCD window.