[SciPy-user] FITS images with header-supplied axes?

Keflavich keflavich@gmail....
Wed Apr 2 13:46:10 CDT 2008



On Mar 31, 7:59 pm, Perry Greenfield <pe...@stsci.edu> wrote:
> On Mar 30, 2008, at 12:38 PM, Keflavich wrote:
>
> > I was thinking no resampling, just put an RA/DEC grid and fit the
> > image into it as well as it can be.  I don't know if it's possible to
> > display rotated pixels, but that would be the most useful behavior in
> > this case.
>
> Just to clarify, do you mean nearest neighbor regridding? It does
> sound like you mean that you would like to see the image rotated to
> have north up. Right?

That's correct.

> > I'm not sure I understand how the transforms would make it easier to
> > display sky coordinates without labeling axes, though.  Are you saying
> > that if the image is already sampled in RA/DEC (or whatever coordinate
> > system) space, then it should be easy to display the RA/DEC
> > coordinates on the axes?
>
> The transforms machinery would allow displaying the image in its
> original orientation and then when the cursor was moved over the
> image, the displayed x, y coordinates could display RA, DEC instead
> of pixel coordinates. But if you desire to rotate the image and have
> it aligned with north, that capability isn't really important. Doing
> the rotated image needs some tool to do the rotation (quickly
> presumably rather than a precise mapping) and then display that as
> part of a larger tool. That would be much more straightforward. But
> we haven't made such a tool yet. If someone does it first, it sure
> would be nice to add, at least as part of an astronomy toolkit.

OK, I didn't realize that the transforms work as you describe, I'll
have to test that.  If I can get something like the tool you described
running, I'll post my results here, but I'm going to may slow progress
if any.

I'm not clear how I would go about making usable paper figures in
Python without this capability, though, so what does everyone else
do?  Just use other tools for figure generation?

Re: Nicolas and Tom
Is the astropy mailing list active?  I've attempted to subscribe but
haven't received confirmation or any list e-mails.  Otherwise, perhaps
just listing things on the wiki is enough, or keeping a list via this
group?

Adam


More information about the SciPy-user mailing list