For the SAs and OAs and CFH12K observers in particular, please read this 
description of the latest evolutions of the CFH12K observing environment.

		CFH12K session upgrades - March 27th 2000

1: Improved prime focus bonnette focus setting
2: Automatic focus adjustment when selecting a filter
3: Interruption of sequences
4: Flux command
5: Twilight Flat-Fields Sequencer Flux Monitoring
6: CFH12K mosaic map
7: CFH12K Observing Log Sheet
8: Logging temperatures

1: Improved prime focus bonnette focus setting
The script "pfocus" (also used from the GUI), now has all kind of checking 
to make sure the bonnette is not driven into its limits. Also the motion has 
been optimized (remember that the z desired position has to be reached from 
below), to gain some seconds when going in the up direction.  Typically, to 
go from one position to an upper position is about 20 seconds, and 30 seconds 
to go to a lower position.

2: Automatic focus adjustment when selecting a filter
The command "newfilter" (called automatically from the GUI), will adjust 
the prime focus bonnette "z" stage when a new filter is selected based on the 
offsets I calculated from a large set of statistics, see the following document
for the values:

This will work ONLY if the proper name for the CFH12K is used (the script bases
its decision on the name, not the position). This means you have to stick to the
following norm, type "newfilter" with no argument in the DIRECTOR window to 
get the following message when in doubt:

Usage = 'newfilter POSITION NAME'
Will put selected filter in the beam and will adjust focus position
Filters available (4 at once in CFH12K): B, V, R, I, Z, Ha, HaOFF
Example = newfilter 3 Z

NOTE: The Z filter (Z prime), should be name "Z", that's enough to know what 
filter it is. Otherwise, the "'" character is too tricky to handle through the 
GUI, script, etc...

If the filter is unknown (the script does not support TiO and CN for example),
then a warning message appears in DIRECTOR.

3: Interruption of sequences
-> dithering patterns & twilight flat-fields sequencer

I implemented Sidik's recipe to handle signals in the script and it works fine.
I added a line in the GUI for the section "flat-fields sequencer" and "dithering

        "Use the "Stop", "Break" and "Abort" buttons to control the sequence"

That means that the button in the "Exposure" area are to be used to also control 
the sequence ("Break" will stop the sequence after the current exposure is 
completed, "Stop" will stop immediately the current exposure and save it to disk
and stop the sequence, "Abort" will kill both the current exposure and the 

Note that for the dithering patterns, an interruption won't allow the telescope
to be send back to its initial position.

For the twilight flat-fields sequencer, you can now break the sequence as soon 
as you see the algorithm diverge and then restart it with a appropriate exposure
time (see below in this text on how to track the flux easily)

4: Flux command
There is now a flux command that sets the parameters to take a 200x200 centered
raster on CCD08. It displays it in SAOimage and most importantly gives its level
in ADU (corrected for the offset) in DIRECTOR. The flux exposure will use the 
exposure time defined by the user (see the observer user's guide). The initial 
user's settings (etype, raster, ...) are restored after the flux exposure.
Here is the feedback you get when you click on the "Flux exposure" button on 
the GUI (confirm window pops up first) or from the DIRECTOR window ("flux" 

Cannot generate preview image with subraster selected.
Done writing files `flux*.fits'
Displaying CCD 08 of flux
Saving separate FITS files for each chip.
Displayed CCD 08 (200x200 pixels) [saturation above 65K ADUs]
Sky level =  1788 ADUs (offset = 800 ADUs subtracted) 

CCD08 has a normal saturation behavior. If the level in ADUs is above 
60,000 ADUs, that means true saturation.

Here is what I wrote in the observer user's guide about the use of the flux

This function will setup the raster parameter (and will restore the initial 
setting afterward) to select a small central area of each CCD and measure the
flux level of CCD08 (highest gain within the mosaic) to feed the value back to 
the user. This function is intended to be used prior an automatic twilight 
flat-field sequence to quickly monitor the evolution of the sky brightness. 

5: Twilight Flat-Fields Sequencer Flux Monitoring
By the time a full frame readout is completed and 12kcom ready to take another 
exposure, the flux from the exposure will be displayed in the DIRECTOR window. 
If you see the flux going too low or too high, interrupt the sequence and 
restart it with an appropriate exposure time.
Note: this works only for the SPLIT mode (mef off).

Here is the typical feedback for each "etype f" exposure (flat-field):

The current data frame is now 526924f*
Sky level on CCD08 =  13465 ADUs (offset = 800 ADUs subtracted)

Soon this value will be used by the program to adjust automatically
the exposure time (feedback). Eventually the twilight flat-field script
will find out automatically when to start and the user will provide 
simply a list of filters and the ratio of exposures needed (e.g. 
tf12k B=50% R=30% I=20%). One of the key element of a fully automated
mode is the software controlled slew of the telescope Rosemary and Bill 
plan to test next week.

6: CFH12K mosaic map
I added a map of CFH12K showing the position of the outputs relative to the 
North/East axis. Also given are the mapping from the MEF extension number 
(01 to 12) vs. the CCD name (00 to 11) and the gain for each CCD.

7: CFH12K Observing Log Sheet
At the bottom of the main GUI, there is now a button to print an observing 
log sheet for CFH12K. It prints only one sheet at a time on the "sps" printer 
at the summit.

8: Logging temperatures
At the bottom of the DIRECTOR window, you'll now see:

Telescope temp.=-2.13 deg.C. - Dome air temp.=-2.19 deg.C. - PFBz=1.594 mm

It will be refreshed every 5mn. This information collected over the course of 
the next CFH12K runs will allow soon to adjust automatically the focus during 
the night when temperature changes occur.

Wiley did some calculations that confirm the numbers we saw during some extreme 
nights: a change of 7 deg.C. causes a change in length in the tube trusses of 
0.56mm (total length is ~ 7m).

There are no sensors on the tube trusses currently. Some need to be installed 
to allow proper measurement and precise prediction of focus change (for now 
I'll use the one on the caisson).

Jean-Charles Cuillandre
Canada-France-Hawaii Telescope Corporation, 1999