[AstroPy] Co-ordinating Python astronomy libraries?

Erik Tollerud erik.tollerud@gmail....
Wed Jul 21 22:57:11 CDT 2010

> One package for any model fitting? That does not seem very reasonable. Even
> xspec does not come close to this!
> Model fitting is a ultra high level analysis tool. I do not think that we
> are at the stage that we can contemplate this kind of issues.
> I am doing single photon high-energy astrophysics  (Fermi LAT data) : I can
> assure you that my spectral needs are totally different from a CCD based
> spectral analysis "a la" X-rays....

Oh, you're absolutely right that the functional forms, parameter
selection techniques, statistical analysis, and the like will be very
different for different problem domains.  But my point is that all of
this can be encapsulated in classes with common interfaces.  That is,
if you write a parametric model that maps a scalar onto another
scalar, it should be easy for you to stick that in a class that lets
you specify a particular data fitting technique, but not have to write
your own special GUI every time you design a new 1D parametric model.
And it should be super trivial to write a model and have the basic
fitting methods "just work" out of the box.

That is, while model fitting (and for that matter, any given model) is
indeed ultra high level, the general framework of a 1D parametric
model with data (and errors) and the basic tasks of plotting and the
like are actually fairly low level, and I would say that means they
should be in the base classes so we can more easily leverage each
others' work to get out more science.

> But I still need a seamless way to
> interface WCS and easily visualize astronomical data, with contour overlaid
> etc..., whatever the underlying system of coordinates used or the projection
> method requested.

Agreed! At least about WCS - I think lots of people have pretty
application specific ways of overlaying things on WCS, but the
appropriate tools to do that fairly generically are the key.

Erik Tollerud
Graduate Student
Center For Cosmology
Department of Physics and Astronomy
2142 Frederick Reines Hall
University of California, Irvine
Cell: (651)307-9409

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