MCCT SKADS Mixed Workshop
Towards third generation calibration in radio astronomy
SKADS Set of Standard Challenges
Participants of the workshop, which will be held in Nançay
(France) from 27 Sept to 10 Oct 2009, will be selected and notified
not later than Sept 1st.
To qualify, we would like you to work through your own selection of
the Open Challenges of the “SKADS Set of Standard Challenges” (SSSC),
which you can find at:
NB: These instructions are also available on this website, together
with lots of other supporting information, and a list of answers to
Frequently Asked Questions about what we are trying to do. Your
friendly contact for all matters pertaining to this site is Ian
ianh at astro.ox.ac.uk
Each item in the list of Open Challenges is based on a data-set (MS)
with simulated uv-data. These are generated for an existing instrument
(e.g. the WSRT), using a particular Local Source Model (e.g. a point
source), and corrupted with a specific set of instrumental errors
(e.g. antenna phases that vary sinusoidally with time).
The “difficulty” of an item is indicated with a rating (one or more
stars). You will notice that the first ones are variations on the theme
of a single point source in the centre of the field. Since we are
working hard to stay just ahead of you, more interesting items will
appear by the time you are ready for them.
The PURR log in the first item will guide you trough the various
steps: Looking at the uv-data, trying to subtract the LSM from it, and
solving for the corrupting instrumental errors. In principle, you can
use any 2nd generation data reduction package of your choice to do all
this. But in view of the 3GC Challenges to come, we really recommend
that you invest the time to master MeqTrees.
Whatever tools you use, we ask you to report your findings in the form
of PURR logs (see below), marked with your name, email address and
other useful information. Please send your PURR logs to Jan Noordam:
noordam at astron.nl
While we will give points for zeal (e.g. if you work through all the
available Challenges), we are more interested in other traits (see
also below). We will be particularly impressed with people who go one
step further, and generate new Open Challenges of their own. For
instance by making interesting variations on the ones that are already
there. Instructions for doing so are in another PURR log in the first
Challenge. With your consent, we will put your new items on the SSSC
page, for others to play with, and to make their own variations on.
If you get carried away, and want to use your special skills to
contribute something to our tools, we will be pleased to offer you
Somewhere in August, we will introduce some special Challenges that
deal with the two main themes of our workshop, i.e. station beamshapes
(EJones) and ionosphere (ZJones and FJones). For some of you, this
might be the moment to specialize a bit.
This is all you need to know to start. We hope that you will enjoy
this exercise, and feel that it opens new ways of doing things, and
particularly of doing them together. We very much look forward to
getting to know you, and to see what you can do.
(One more thing: If you know anyone else who would enjoy participating
in this, just pass on this information, and tell him or her to start
sending in PURR logs. Registration is not necessary.)
- Jan Noordam
- Ian Heywood