→ Widely unknown Exoplanet Astronomer

SAOImage DS9 is an astronomical imaging and data visualization application used by professional astronomers to view their astronomical images. It is a great application to use when viewing .fits files.

DS9 displaying the M3 cluster in R band taken with the Nordic Optical Telescope in La Palma

The application is cross platform and can be used on Windows, Linux and Mac. It quite easy to install and can be downloaded from http://hea-www.harvard.edu/RD/ds9/.

I have provided a sample fits file of M3 which you can use to play with the application: M3.fits To save this file right click on the link and choose “save link as” from the menu.

Open DS9 and choose File >> Open…

Navigate to where you saved the .fits file and press OK.

Next you can press the ZOOM button followed by “to fit” below it on the left.

Next choose SCALE followed by the “log” button. This should show you more stars.

Next hold the right mouse button down on the image and move the mouse around. Up and down changes the contrast whilst left and right changes the scaling.

Feel free to play around with the application. Notice how at the top of the application you are given useful details such as pixel value, image coordinates and sky coordinates. Pretty neat huh?

IRAF is short for Image Reduction and Analysis Facility and it is a program widely used by professional astronomers to reduce their data. The program if free and readily available on the web, so in theory there is nothing stopping amateurs from using the same software to reduce their images. IRAF has not changed much over the years, and many people starting off in IRAF will find it hard to deal with a command based program instead of a GUI (Graphical User Interface).

IRAF welcome screen

IRAF can be used on a number of platforms although it is mainly used on UNIX based systems such as Mac and Linux. The installation can be tricky, especially if you have not done it before. The full IRAF working environment requires two other pieces of software to be installed: DS9 and xterm/xgterm. IRAF will work without these environments being installed, but then you will not be able to display your astronomical images.

IRAF can be downloaded from: http://iraf.noao.edu/ and a support forum is available at: http://www.iraf.net/