Table 1: Journal of observations.
Spectroscopy

CAHA (PA=121 $^{\circ}$ , width=1.2 $\hbox{$^{\prime\prime}$ }$ , 1998-08-27/28)

range: $\lambda$ (Å) $\Delta\lambda$ (Å/pixel) exposure (s)

B: 3595-5225 0.81 $4\times1800$

R1: 5505-7695 1.08 $2\times1800$

R2: 7605-9805 1.08 $2\times1800$

ISO/SWS ( $\rm PA=-29^{\circ}$ , data set 81601775, 1998-02-08)

line range ( $\mu$ m) aperture ('')

[S IV] $\lambda$ 11 $\mu$ m 10.45-10.55 14 $\times$ 20

[Ne III] $\lambda$ 16 $\mu$ m 15.46-15.64 14 $\times$ 27

[S III] $\lambda$ 19 $\mu$ m 18.61-18.77 14 $\times$ 27

[O IV] $\lambda$ 26 $\mu$ m 25.80-26.08 14 $\times$ 27

[S III] $\lambda$ 34 $\mu$ m 33.17-33.75 20 $\times$ 33

[Ne III] $\lambda$ 36 $\mu$ m 35.70-36.26 20 $\times$ 33

ISO/LWS

Data set Spectrometer Exposure (s)

59901081 LWS01 1478

80800268 LWS02 810

81601776 LWS01 1402

Imaging

JKT (1990-08-20/21)

Band Filter Exposure (s)

H $\beta$ 4861/54 $2\times1800$

H $\alpha$ 6563/53 1800

H $\alpha$ continuum 6834/51 1300

[O III] $\lambda$ 5007 5007/51 1800

**Table 1:** Journal of observations.
Spectroscopy
CAHA (PA=121 $^{\circ}$ , width=1.2 $\hbox{$^{\prime\prime}$ }$ , 1998-08-27/28)
range: $\lambda$ (Å)	$\Delta\lambda$ (Å/pixel)	exposure (s)
B: 3595-5225	0.81	$4\times1800$
R1: 5505-7695	1.08	$2\times1800$
R2: 7605-9805	1.08	$2\times1800$
ISO/SWS ( $\rm PA=-29^{\circ}$ , data set 81601775, 1998-02-08)
line	range ( $\mu$ m)	aperture ('')
[S IV] $\lambda$ 11 $\mu$ m	10.45-10.55	14 $\times$ 20
[Ne III] $\lambda$ 16 $\mu$ m	15.46-15.64	14 $\times$ 27
[S III] $\lambda$ 19 $\mu$ m	18.61-18.77	14 $\times$ 27
[O IV] $\lambda$ 26 $\mu$ m	25.80-26.08	14 $\times$ 27
[S III] $\lambda$ 34 $\mu$ m	33.17-33.75	20 $\times$ 33
[Ne III] $\lambda$ 36 $\mu$ m	35.70-36.26	20 $\times$ 33
ISO/LWS
Data set	Spectrometer	Exposure (s)
59901081	LWS01	1478
80800268	LWS02	810
81601776	LWS01	1402
Imaging
JKT (1990-08-20/21)
Band	Filter	Exposure (s)
H $\beta$	4861/54	$2\times1800$
H $\alpha$	6563/53	1800
H $\alpha$ continuum	6834/51	1300
[O III] $\lambda$ 5007	5007/51	1800

Source LaTeX | All tables | In the text

	1 Introduction
	2 Observational data and reduction
	3 Empirical diagnostics
	4 General strategy for model fitting
	5 Simple models
	6 Models with constrained density distribution
	7 Further refining of the models
	8 Sources of energy other than the ionizing flux
	9 Uncertainties in O/H and Ne/O
	10 Conclusion
	References
	Online Material
	Appendix A: Correction of Balmer lines used for dereddening
	Appendix B: Setting the geometric corrections A, B, and K