As with the previous IR array control software, ``parameter sets'' are used to control the attributes of data acquisition. A listing of the parameters is given below. Because the data are saved directly as IRAF images, note that parameters include not only observation-specific items such as integration time, but archiving items such as the IRAF filename and the header and pixel directories.
| Observing Parameters | |
| Parameter | Meaning |
| coadds | number of coadded integrations per image |
| lnrs | number of low noise reads |
| pics | number of pictures per observation |
| integration_time | integration time (seconds) |
| filename | IRAF filename |
| header_dir | image header file directory |
| pixel_dir | pixel file directory |
| mode | process mode |
| nextpic | picture index |
| ucode | microcode |
| display | channels to display [only one for IRS] |
| ra | RA of object * |
| dec | DEC of object * |
| epoch | epoch of object * |
| offset | observation offset |
| imag_typ | type of observation [object,dark,flat..] |
| airmass | airmass of object * |
| object | object name |
| comment | comment |
| im_list | filename of image list |
| title | IRAF header title |
| save | channels to be saved to disk [only one for IRS] |
In general, the parameters fall into three categories:
The command ped will open an editing session on the current parameter set, listing each parameter in turn and prompting for new entry (<cr> returns the present value). At the beginning of a run, one should execute ped and set up those parameters falling into categories 2 and 3 above. NOTE: One cannot specify a non-existent header or pixel directory in ped; it is necessary to go to the IRAF XTERM window and create those directories first! To select the parameters for which you will be prompted when you make an observation, there is a command eask, which runs through the entire parameter list, permitting the observer to specify which parameters will be queried (specified by a), or listed (specified by l). Entering la for a parameter selects it to be both queried and listed (by plist). NOTE: The ``up arrow'' key may be used to back up through the ped list if one wishes to change a previously entered parameter.
When this is complete, save the parameter set with the command psave <filename>. This will save both the edited parameter set and the menu selected by eask in the file `<filename>.par'. Should the system crash, this information may be retrieved by the command puse <filename>. Should major changes be made to the parameter file, such as change of header or pixel directory (say on another night of the run), it is a good idea to psave the updated file so it, and not the previous version, will be recovered by puse.