Astronomical Data Visualization at NYU

Color representation of multi-band imaging

[Wherry, Blanton, Hogg, Lupton]

Modern astronomical images generally have far more dynamic range than can be represented by any reasonable output device, including computer displays and printers. We have developed a method for representing the images that displays a large dynamic range and preserves color information, even in saturated parts of the image.

Compare our new representation of the Hubble Ultra Deep Field to the traditional representation by the NASA HUDF team.

Compare our new representation of the Hubble Deep Field to the traditional representation by the NASA HDF team.

You will see that in our new representations you can:

• see the (colored) diffraction patterns inside the stars,
• see spiral arms or elliptical structure inside the brightest galaxies,
• see the central, red parts of galaxies as red and not "hot white",
• distinguish galaxies with and without color gradients,
• see that higher-redshift galaxies are "painted with a different palette" than lower-redshift ones, and
• yet still see all the faint galaxies just above the detection threshold.

references

Lupton, R. H., Blanton, M. R., Fekete, G., Hogg, D. W., O'Mullane, W., Szalay, A., Wherry, N., 2004, Preparing red-green-blue (RGB) images from CCD data, Pubs. Astron. Soc. Pac., in press

download

Requirements

UNIX, IDL, wget (or replace wget in the Makefile with curl)

A few Mb of space

Instructions

Download this Makefile into an empty directory.

Enter that directory and type “make”.

Notes

The Makefile downloads a tiny bit of code and a few test images from NYU. Most of the code that it downloads has nothing to do with visualization but is just an IDL FITS reader. It then builds a pretty picture called “hdf_wherry.jpg” in the working directory. The code “make_hdf_jpeg.pro” is the documentation. It is not complex.

Two-dimensional representation of multi-dimensional point sets

[Coming soon.]