We start
with the Setup Window. Parameters for this window must be set before we
do anything else with NIRIM.
N.B. NIRIM does NOT provide the standard
WIYN headers with RA, DEC, etc!
This is a window where you can set up information to go into the fits
headers. Note that much of this
information must be set manually each time you want to update it. There is a “template” file you can select
that automatically inputs the observatory, telescope, instrument, and
detector. It is data1/nirim/irtoolsetup/wiyn_fitsheader. You can select this template by clicking on
the “file” button in the FITS header window and loading the wiyn_fitsheader
file. Within the FITS header
parameters, those that will be automatically updated include: simple, bitpix, naxis, naxis1, naxis2,
prescan, postscan, istart, and jstart.
The parameter ‘exposure time’ is taken from whatever exposure time you
input to the exposure window (see next section). Likewise, ‘irafname’ is taken from whatever you input as the
image file name in the exposure window.
But if you wish to keep track of the exposure type, object name,
observer, observation date, UT time, sidereal time, right ascension,
declination, epoch, airmass, and filter, you will need to update that
information by hand for every exposure
you wish to keep track of. Otherwise it
simply writes the same information over and over again. Remember to hit “apply” when you
are done, or it will not take all the information you just input!
This is
the business window that you will be using over and over again to take an
exposure. You can set the exposure time, the raw data directory, and the name
of the image file that will be created. We strongly recommend that you first create a “raw data” directory
where you will store all the raw data.
(In a terminal or Xgterm window on sand, assuming you are in the
/data1/nirim directory, do a “mkdir xxxx”, where xxxx is the raw data
directory. Then in the exposure window,
the image file name should be /data1/nirim/xxxx/yyyy####, where “yyyy” is
whatever you would like to call the fits images, e.g. dark, skyflat, etc., and
#### is whatever number you would like to start the counter at, e.g.
0001.) Image names will be incremented
by their trailing digits with each exposure.
In order to ensure that the image number is incremented with each
exposure, you should check the square next to “auto increment”. N.B.
Do NOT put a “.fits” on the end of the image name. If
you do that AND/OR do not hit the “auto increment” button, the program will
just keep overwriting the same file!
When an
exposure is in progress an “Abort Exposure” button will appear. DO NOT CLICK ON THIS BUTTON. Trying to abort the exposure will hang the
software.
This
window is also used to display the temperature of the NICMOS3 array and
consequently, the dewar interior. The
temperature should read ~ -196ºC. If
the temperature is more than a couple of degrees different from -196ºC, there
may be a problem. Have the OA top off
the dewars with LN2. If the
temperature still warms up over the course of the night (by more than 10
degrees or so) the dewar(s) may have gone soft and need to be pumped down to
vacuum again. Please have the OA notify
WIYN personnel.
There is a
button in this window that says “Flush Array”.
IGNORE IT. There is also always an error message that
says “Array temperature out of range”. IGNORE IT, TOO.
The FITS
image file is a 256x512 image that is composed of two reads of the NICMOS3
array. The first read is taken
immediately after the IDLE cycle, which is continuously resetting the array.
The total read time is about 0.2 seconds. Note that there is no shutter for the
camera. After the first read, the array absorbs photons for the time specified
by the exposure time and is then read for a second time. The difference between these 2 reads is your
image minus the background levels in the array.
This menu window allows the observer to select filters. Push the filter button that you would like. Both filter wheels will turn to produce the desired filter selection. If you think the filters have gotten confused, hit the home buttons at the bottom of the menu window. “Home” is defined as when filter wheel #1 is in the cold plate position and filter wheel #2 is in the open position. If the filter wheels hang, check to make sure that the power is on for the black stepper motor power supply.
For all selected filters, open is the desired position of the other filter wheel. Note: for historical reasons, the 2.295µm CO band head filter (in filter wheel #1) and the 1.064µm continuum filter (in filter wheel #2) are linked. When you select either filter, the program will automatically go to the other filter as well, so you need to manually select the “open” position. For example, if you select the 2.295µm CO band head filter in filter wheel #1, you will need to select the “open” position in filter wheel #2. In all other cases, when you select a filter, the program will automatically go to the “open” position in the other filter wheel.
See Figure 1 for the orientation and location of the filters in the two filter wheels.

Figure 1. NIRIM filter complement
This menu
is for "engineering purposes" and may eventually be phased out. It permits the user to fiddle with the
digital signal processing code directly - not generally a good idea for the
first time user. It has been used
occasionally to change filter wheels and check the positions of the home
switches on the filter wheels and stepper motors. However, all of these
functions can and should be handled from the other menus.