CADE FAQ & Community

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CADE Mailing List

If you use CADE data, please join our mailing list. The purpose of the list is to regularly update users with CADE news, and to receive user feedback and suggestions. Your input helps us to extend and improve the CADE database of maps and tools.

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Getting Help

Some of the recurring questions that we receive appear below in the FAQ. If you still don't find an answer to your question, please write to us at


Can CADE generate a Healpix cube corresponding to a spectral line data set?

At this time, CADE only delivers two-dimensional Healpix maps since the memory requirements for manipulating cubes in Healpix format are prohibitive. For historical reasons, the initial maps from spectral line surveys delivered by CADE were integrated intensity (moment-0) and column density maps for HI surveys. We are in the process of adding other 'moment' maps (e.g. peak brightness and velocity centroid maps) to the CADE database, and expanding the database to include more molecular line surveys.

If you are searching for a Healpix map of a two-dimensional quantity derived from a spectral line survey, don't hesitate to contact us

What is the resolution of my Healpix map?

The original angular resolution of the surveys is determined by the instrument, and is noted on the individual survey pages. Some maps in the CADE database have been smoothed to a lower angular resolution, following the process described on the individual survey pages. The final angular resolution of the distributed CADE maps is included in the FITS header using the BMAJ/BMIN keywords.

The NSIDE of a Healpix map determines the pixelisation scheme and hence the pixel size. At CADE, we aim for a pixelisation scheme such that there are 2 to 3 pixels across each resolution element. For convenience, the following table shows the conversion from NSIDE to pixel size.

NSIDE Pixel Size Input Resolution*
[as] [as]
256 825 1980
512 413 990
1024 206 495
2048 103 248
4096 52 124
8192 26 62
16384 13 31

* assuming 2.4 pixels per resolution element

Can I have a version of a CADE Healpix map in Equatorial coordinates?

Yes (probably). For historical reasons, most maps distributed by CADE use a Galactic coordinate system. For some surveys, we distribute maps in both Galactic and J2000 coordinates (see the individual survey pages). Please contact us at if you don't find the map in Equatorial coordinates that you are looking for.