adapt for API change for photutils areas (#193)

[sosey]

Update the logic to account for differing APIs in photutils version >= 0.7

[sosey]

Fixes #193 and #194

[sosey]

Everything looks clean on my end, I'm going to merge this so I can make a formal release

[hjmcc]

Many thanks for the changes! We are almost there. Aperture sum works, curve of growth works. However, I see a new bug now in the radial plot ('r') mode:

----> 1 viewer.imexam()

~/anaconda3/envs/py37-astropy/lib/python3.7/site-packages/imexam/connect.py in imexam(self)
    148                 self._run_event_imexam()
    149             else:
--> 150                 self._run_imexam()
    151         else:
    152             warnings.warn("No valid image loaded in viewer")

~/anaconda3/envs/py37-astropy/lib/python3.7/site-packages/imexam/connect.py in _run_imexam(self)
    264                                     self._check_slice()
    265                                 self.exam.do_option(
--> 266                                     x, y, current_key)
    267                 except KeyError:
    268                     print(

~/anaconda3/envs/py37-astropy/lib/python3.7/site-packages/imexam/imexamine.py in do_option(self, x, y, key)
    190         """
    191         self.log.debug("pressed: {0}, {1:s}".format(key, self.imexam_option_funcs[key][0].__name__))
--> 192         self.imexam_option_funcs[key][0](x, y, self._data)
    193
    194     def get_options(self):

~/anaconda3/envs/py37-astropy/lib/python3.7/site-packages/imexam/imexamine.py in radial_profile(self, x, y, data, form, genplot, fig)
   1076             self.log.info("Background per pixel: {0:f}".format(sky_per_pix))
   1077
-> 1078             flux -= sky_per_pix
   1079
   1080             if getdata:

UFuncTypeError: Cannot cast ufunc 'subtract' output from dtype('float64') to dtype('uint16') with casting rule 'same_kind'

I am not sure what this is coming from, I will investigate. Thanks!

[hjmcc]

It could be that my FITS data (from a small telescope we are using here for teaching) has BITPIX=16 and something is not being converted correctly.

If I do this

flux = flux - float(sky_per_pix)

all works!

[sosey]

could be, do you have BSCALE and BZERO also in your data headers? It may not be translating the 16bit on read correctly, what are the values for those keywords in your data?

physical value = BSCALE * (storage value) + BZERO

[hjmcc]

Hmm, seems to be fine:

BZERO   =                32768 / offset data range to that of unsigned short    
BSCALE  =                    1 / default scaling factor

the data is BITPIX=16

Incidentally, the point of this project is to find a simple tool we can use with students to explore astronomical data, and this tool seems great...

[sosey]

hmm..I'll look at the flow of the sky pix then...

awesome! lemme know how it goes or if you see any shortcomings that we can fix, feel free to make issues for those too :)

[hjmcc]

thanks!

Sure, check out @hjmccracken on twitter for pictures of our observatory (in the centre of Paris!) . I have been looking for a long time for a simple tool to use with students, ds9 does a lot of stuff but it's not quite there.

Cheers henry

On Fri, 6 Dec 2019 at 21:36, Megan Sosey notifications@github.com wrote:

hmm..I'll look at the flow of the sky pix then...

awesome! lemme know how it goes or if you see any shortcomings that we can fix, feel free to make issues for those too :)

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[sosey]

I have been there! :) (ADASS 2011)