In this example, we will compute a spherical model and study the effect of putting the aperture in different locations on the image of the object.
We can compute the line intensities (relative to Hbeta) for the whole nebula or through the slit, and compare the 2 results:
line: H__1__4861A I/Ib Total: 1.0000 I/Ib Slit: 1.0000 Delta: 0.0% line: H__1__6563A I/Ib Total: 2.8887 I/Ib Slit: 2.8894 Delta: 0.0% line: HE_1__5876A I/Ib Total: 0.1826 I/Ib Slit: 0.1854 Delta: 1.6% line: N__2__6584A I/Ib Total: 1.1683 I/Ib Slit: 1.0199 Delta: -12.7% line: O__1__6300A I/Ib Total: 0.0195 I/Ib Slit: 0.0159 Delta: -18.4% line: O_II__3726A I/Ib Total: 0.7679 I/Ib Slit: 0.6819 Delta: -11.2% line: O_II__3729A I/Ib Total: 0.3426 I/Ib Slit: 0.3040 Delta: -11.3% line: O__3__5007A I/Ib Total: 3.7708 I/Ib Slit: 3.9727 Delta: 5.4% line: TOTL__4363A I/Ib Total: 0.0153 I/Ib Slit: 0.0159 Delta: 4.3% line: O__1_6317M I/Ib Total: 0.0024 I/Ib Slit: 0.0020 Delta: -16.1% line: O__1_1455M I/Ib Total: 0.0001 I/Ib Slit: 0.0001 Delta: -15.6% line: C__2_1576M I/Ib Total: 0.0000 I/Ib Slit: 0.0000 Delta: -12.2 The ipython notebook can be seen there: https://github.com/Morisset/pyCloudy/blob/master/pyCloudy/docs/Using_pyCloudy_4.ipynb