Palomar 200" PFIRCAM Operation & Instructions

Contacts:

Tom Jarrett (o: 818-397-9538; h: 818-309-1220)

jarrett@ipac.caltech.edu

Chas Beichman (o: 818-397-9500/9502)

chas@ipac.caltech.edu

Nick Gautier (o: 818-354-7204)
Carl Bruce (o: 818-354-5480)

Basic Overview

PC Setup

The software that controls the camera is MS-Windows based. The user should be within the Windows environment. The data acquisition program is called "Pfircam". With the mouse double click on the icon "Pfircam" (should be located in the group folder "PFIRCAM"). A window will open with a blank green background titled "Focal Plane Array Evaluation". Click on "File" and move mouse cursor to option "Remote Cntrl" and click on this (note: only one click is required). Now the PC is configured for a socket network connection to Tardis.

** Note ** If the network connection between the PC and Tardis somehow becomes corrupted (either the PC is hung or the Tardis is hung) then you must restart this program: Close the current "Pfircam" window. (meanwhile you must also shutdown the socket connection on the Tardis side of things; see below.) Now start up the program: Double click on the icon "Pfircam". Click on "File" and move mouse cursor to option "Remote Cntrl" and click on this. You must then establish a socket connection on the Tardis (see below).

Tardis Setup & Operation

The user will acquire data, rotate filter wheels and move the telescope using the "Tardis" Sparc workstation. The filters and the telescope are controlled using RS-232 serial connections between Tardis and the telescope computer and the filter wheel stepper motor computer modules (located in the prime focus cage). Camera operation (data acquisition) is performed within the IRAF environment (Tardis to PC via TCP socket connections).

Serial Connections

Both Tardis A/B serial ports must be properly configured for communications. The device ports are /dev/ttya and /dev/ttyb. The actual device files are located in /devices/obio/

/dev/ttya == zs@0,100000:a /dev/ttyb == zs@0,100000:b

*** Make sure that these files have the appropriate protections (i.e., they are not protected). If they are, then you must change them as follows,

chmod 777 zs@0,100000:a

and likewise for the other file. To automatically fix the devices, type "fixdev" at the unix prompt.

Filter Wheel Operation

In the Tardis window "Filters" execute the filter wheel driver program:

cd /palomar/filters (or type "tofilter")
fdriverIp>

You are now in the filter wheel driver environment; type "init" this will initialize the filter wheel current location (you must know in advance what the current filter wheel position is);

To list the available set of filters, type "list 1" or "list 2", where 1 and 2 refer to filter wheels 1 and 2, respectively. To move to a different filter, type (e.g.,) "go k", this will rotate the wheels to the "k" band position. Written to screen will be various information about the particular filter (e.g., the recommended focus position).

For a list of available commands, type "?". To reinitialize the filter wheel setup, type "init".

Tardis - PC Socket Connection Setup

Go to the Tardis window "Camera". You will now establish the network connection with the PC (presumably you have already set up the PC for this network connection; see PC setup above). Type the following command:

"startcom"

You will see verbose text written to the screen commenting on the attempt at a socket network connection. If all goes well, the final message will read "connection established; operation now in progress; connected". In the iraf window, type "socket init" (see below for futher iraf instructions).

A typical problem that may occur is that a connection is refused due to a port conflict:

"net: failure to bin port 7020 for service pfircam

bind: address already in use"

Do not panic. This problem is easily solved as follows: In the IRAF window "Pfircam" type the command "socket con". (here you need to be in iraf, and you must have loaded the pfircam cl tasks; see below) Now you will notice in the "Camera" window that a connection has been established (if not, then try again "socket con"). Now type "socket init". You may also fail to establish a connection if the PC is not properly configured (see PC Setup).

Tardis IRAF/Data Acquisition

Data acquisition (and simple image reduction) is performed from the IRAF environment. A set of iraf "cl" tasks have been prepared to perform these operations. Go to the Tardis window "Pfircam" and start up iraf:

cd /palomar/visitor (or type "toiraf")
cl

Now load the pfircam cl task package:

pfircam

First see what the status of the socket connection is. The task "socket" serves as a simple interface for the Tardis - PC network connection;

socket init


socket status {this will tell you the current socket status; this information is written within the Tardis window "Camera"}


socket ? {lists the various commands}


socket con {this += the current binding address; use this command when you fail to establish a socket connection in the "Camera" window: "net: failure to bin port 7020 for service pfircam bind: address already in use"


socket exit {to close the socket connection}

To move the telescope and in arc seconds; e.g.,

move 5 -10 {move telescope 5 arcsec east, 10 arcsec south}

epar detpars

Now set the proper image sequence number using "picnum" (for description, see below); e.g., "picnum 100"

Test Exposures

You may want to take some test data to see if the connections are properly configured and to see how the camera is performing. ( ! Make sure you have the proper filter loaded! ) The task "irquick" will perform most test exposures.

e.g.,
irquick 1 {take a 1 second exposure}

Note: to fiddle with display parameters, "epar display"

When you are finally getting serious about taking data, you are then ready to configure your beam-switching pattern.

Beam-Switching Patterns

There are three modes of beam switching that may be used: smallsky, bigsky, and custom. Here smallsky refers to a small beam throw (typically ~30 arc sec), bigsky to a large beam throw, and custom to a user designated beam throw pattern. Smallsky is typically used for standard calibrator observations and other point sources (where you "dither on chip") and bigsky is used for galaxy and other large extended objects, and custom is used for those complicated regions of the sky.

Build a beam switch pattern using the appropriate task: smallsky, bigsky or custom. Practice a bit with these tasks to become familiar with building various beam-switching patterns. They are designed to be a tool to both visualize the beam switch pattern and to construct a suitable pattern to be used with the task "observe" (described below).

Note: these tasks do not directly affect data acquisition or telescope motion, so they may be used fast and loose.

Example:

smallsky np=4 arc=45 randit=10 {construct 4 on-off pairs; the beam throw between on and offs should be 45 arc seconds; there is a random dither offset for each position (with gaussian sigma = 10 arc seconds); the beam pattern is a diamond}

Taking Infrared Image Data

Normal observations are performed using the task "observe". The user should edit the parameters file to set the appropriate observing parameters: "epar observe". Parameters include: object name, exposure time, # of stacked images, # of on-off beam switch pairs and beam switch pattern (see above).

Examples:

1. observe {before you do this, first "epar observe" and set all the parameters}
2. observe exp=5 nst=1 np=4 beam=bigsky disp+
{4 on-off pairs with a "bigsky" beam-switch pattern; for each, take a 5 second exposure with 1 stacked image; display each image after they are written to disk}

picnum 100

picnum
{returned you get 217, for example; then the next image is nic0217}

observe exp=5 nst=1 np=4 beam=bigsky disp+

Images acquired will be nic0217, nic0218, nic0219, nic0220, nic0221, nic0222, nic0223, nic0224; where we have 4 pairs of images (on-off pairs).

To perform a simple image reduction, execute the task "qproc". This task computes the difference image between the "on" image and the "off" image. For the example above you would type:

qproc 217 224

nic0217mrfb, nic0219mrfb, nic0221mrfb, nic0223mrfb

Note: this task is primarily used to give the user a quick peek at reduced images; there is no flat- fielding, bad-pixel fixing, star masking or cosmic ray cleaning. For more elaborate image reduction, you will want to use the tasks "skyflat" and "process". This tasks are not described here.

With the "quick" reduced images, you may use the task "irexam" to do various display options and image statistics. You may also mosaic (i.e., combine) the reduced images using tasks "mosaic" and "mosaic_auto". The user should (as usual) check the parameters and set the appropriate values; e.g., "epar mosaic".

Examples

1. irexam 217 224
{this will examine reduced images nic0217mrfb, nic0219mrfb, nic0221mrfb, nic0223mrfb}

2. mosaic 217 224
{manually combine the reduced images nic0217mrfb, nic0219mrfb, nic0221mrfb, nic0223mrfb}

One typically focuses using the "irquick" task. After the image is displayed, you may determine the PSF parameters (e.g., FWHM) using the gaussian fitting task "fitpsf"; e.g.,

fitpsf irquick 10
{fit a elliptical gaussian to stars in image irquick.imh using a 10 pixel box}

There is now a task specifically dedicated to the focus procedure:

focus int_time

focus 2

Centering Objects in the FOV

To center the array on a point source, execute task

"tocenter"

Box Statistics

A handy tool for performing statistics on the image in designated sections is a task call "stat_sec". Use this task to check point sources for saturation.