Kyle's Finder Chart Software - IGRINS Observability

This page describes how to use my python code, IGRINS Observably, for making finder charts.  The finder charts are designed to match what you will see in the IGRINS slit view camera field of view.  They can be used for planning observations, and at the telescope to match what you are seeing in the slit view camera.

You can download the latest version of IGRINS Observability on the Software Page. 

IGRINS Observability has the following requirements:

• DS9 7.2 callable from the command line (might work on earlier versions).  You can install manually or with MacPorts.
• XPA for allowing commands to be given to DS9 from the command line.  If you are on a mac and have trouble installing XPA manually, try using Fink or MacPorts to install it.
• Python 2.6 or 2.7 (untested on other versions).  Easiest to install with pip or easy-install.
• Scipy.  Easiest to install with pip or easy-install.
• Matplotlib.  Easiest to install with pip or easy-install.

Setting up input files.

For each target you want to make a finder chart for, you must set up an input file in the /input/ directory.  Your basic input file will look like this:

#Input file for making finder and observability charts
#--------------------Select Charts To Display---------------------------------------
y #Show telescope Hour Angle observing limits
y #Show altitude vs. Local Siderial Time plot with telescope observing limits
y #Show finder chart for IGRINS Slit View Camera FOV
#--------------------Target Info------------------------------------------
135.0 #Sky Position Angle (Start north and go east, N=0, E=90, S=180, W=270 degrees, Default = 90 deg slit oriented east-west)
2 #1=Input object as RA & Dec., 2=Input object name
HD 219485 #Object Coordinates in RA & Dec [hh:mm:ss.ss<space>+/-hh:mm:ss.s], or Object Name
#--------------------Guide Star Info---------------------------------------
0 #Input guide star as... 0=no guide star, 1=dRA & dDec, 2=RA & Dec., 3=guide star name
#Guide star offset in dRA & dDec [arseconds<space>arcseconds], coordinates in RA & Dec [hh:mm:ss.ss<space>+/-hh:mm:ss.s], or Name
#--------------------User Supplied FITS File---------------------------------------
#Fits file path for making finder chart, leave blank if you just want to use 2MASS K-band

I will now break down each of these seperately.

The first part lets the user set which charts to display.  Set to 'y' to display a chart when running IGRINS Observability, set to 'n' to not display the chart.

y #Show telescope Hour Angle observing limits

This displays a chart showing the limits of where the 2.7 m telescope can slew in Hour Angle and Declination.  The observing limit chart is a recreation of this chart, with the declination of the target painted on as red circle.

y #Show altitude vs. Local Siderial Time plot with telescope observing limits

This is an altitude chart showing the altitude of the target above the horizon vs. local sidereal time as the blue line.  The two red vertical lines show the observing limits of the telescope.  These charts are designed to mimic the altitude charts created by http://catserver.ing.iac.es/staralt/ but currently lacks much of the functionality.  If you want to create a night specific altitude chart for multiple objects, or want to see airmass, I recommend you use http://catserver.ing.iac.es/staralt/

y #Show finder chart for IGRINS Slit View Camera FOV

And here we get to the meat of the code, making a finder chart!  The green outline is the Slit View Camera FOV.  The box in the center is the slit.  The Blue compass shows the directions of North and East.  The rest of this manual will go into detail about creating finder charts.

The following part of the input file is where you select your target:

#--------------------Target Info------------------------------------------
135.0 #Sky Position Angle (Start north and go east, N=0, E=90, S=180, W=270 degrees, Default = 90 deg slit oriented east-west)
2 #1=Input object as RA & Dec., 2=Input object name
HD 219485 #Object Coordinates in RA & Dec [hh:mm:ss.ss<space>+/-hh:mm:ss.s], or Object Name

The first line sets the Position Angle (PA) of how you want the instrument's slit pointed at your target on the sky.  The PA goes clockwise from the North where  N=0, E=90, S=180, W=270 degrees.  The default rotation of the instrument is such that the the slit is oriented East to West, so normally the PA = 90 degrees.  WARNING: You should only rotate the instrument +/- 90 deg. from the default position to avoid entangling wires and hoses, so please try to limit your PA to 0-180 deg.  When rotating IGRINS, you will use the encoder on the instrument rotator.  See the Rotation PA -> Encoder table for IGRINS to convert PA to the number on the encoder.  The PA you set will be reflected in how the sky is imaged in the FOV of the slit view camera, as shown below: