Table 1: Evolution of the number of photons, limiting magnitudes and Strehl ratio in function of the number of apertures and in function of the considered mode. Imaging and coronagraphic modes require respectively precision of $\lambda /4$ and $\lambda /100$ . From left to right: 1- number of apertures; 2- minimum, imaging or coronagraphic modes; 3- number of photons needed to achieve the required precision; 4- limiting stellar magnitude for an optical bandwidth of $\Delta \lambda = 4000$ Åand for a constant aperture diameter of 8 m; 5- limiting stellar magnitude for a collecting surface of 150 m² ( $\pi *(8/2)^2*3)$ ; 6- Strehl ratio.
Limiting magnitudes

( $\Delta \lambda = 4000$ Å)

Number Mode Number Strehl

of of photons (in %)

apertures needed d= 8 m $S_{\rm coll}= 150$ m²

per cube

Minimum 64 20.4 20.4 83

3 Imaging 960 17.4 17.4 94

Coronagraphy 32 000 13.6 13.6 100

Minimum 64 20.7 20.7 52

4 Imaging 3200 16.4 16.1 95

Coronagraphy 96 000 12.7 12.4 98

Minimum 160 19.9 19.6 63

5 Imaging 6400 15.9 15.4 94

Coronagraphy 160 000 12.4 11.7 97

Minimum 320 19.4 18.6 63

6 imaging 16 000 15.1 14.4 90

Coronagraphy 160 000 12.6 11.9 97

Minimum 640 18.8 17.6 64

7 imaging 32 000 14.5 13.6 93

Coronagraphy 224 000 12.4 11.5 97

Minimum 960 18.5 17.4 45

8 Imaging 32 000 14.7 13.6 93

Coronagraphy 224 000 12.6 11.5 96

Minimum 960 18.6 17.4 47

9 Imaging 32 000 14.8 13.6 84

Coronagraphy 224 000 12.7 11.5 98

Minimum 1600 18.2 16.9 63

10 Imaging 32 000 14.8 13.6 81

Coronagraphy 320 000 12.41 11.1 95

**Table 1:** Evolution of the number of photons, limiting magnitudes and Strehl ratio in function of the number of apertures and in function of the considered mode. Imaging and coronagraphic modes require respectively precision of $\lambda /4$ and $\lambda /100$ . From left to right: 1- number of apertures; 2- minimum, imaging or coronagraphic modes; 3- number of photons needed to achieve the required precision; 4- limiting stellar magnitude for an optical bandwidth of $\Delta \lambda = 4000$ Åand for a constant aperture diameter of 8 m; 5- limiting stellar magnitude for a collecting surface of 150 m² ( $\pi *(8/2)^2*3)$ ; 6- Strehl ratio.
			Limiting magnitudes
			( $\Delta \lambda = 4000$ Å)
Number	Mode	Number			Strehl
of		of photons			(in %)
apertures		needed	d= 8 m	$S_{\rm coll}= 150$ m²
		per cube
	Minimum	64	20.4	20.4	83
3	Imaging	960	17.4	17.4	94
	Coronagraphy	32 000	13.6	13.6	100
	Minimum	64	20.7	20.7	52
4	Imaging	3200	16.4	16.1	95
	Coronagraphy	96 000	12.7	12.4	98
	Minimum	160	19.9	19.6	63
5	Imaging	6400	15.9	15.4	94
	Coronagraphy	160 000	12.4	11.7	97
	Minimum	320	19.4	18.6	63
6	imaging	16 000	15.1	14.4	90
	Coronagraphy	160 000	12.6	11.9	97
	Minimum	640	18.8	17.6	64
7	imaging	32 000	14.5	13.6	93
	Coronagraphy	224 000	12.4	11.5	97
	Minimum	960	18.5	17.4	45
8	Imaging	32 000	14.7	13.6	93
	Coronagraphy	224 000	12.6	11.5	96
	Minimum	960	18.6	17.4	47
9	Imaging	32 000	14.8	13.6	84
	Coronagraphy	224 000	12.7	11.5	98
	Minimum	1600	18.2	16.9	63
10	Imaging	32 000	14.8	13.6	81
	Coronagraphy	320 000	12.41	11.1	95

Source LaTeX | All tables | In the text

	1 Introduction
	2 Principle of the "dispersed speckles'' algorithm
	3 Minimal photon count found from numerical simulations
	4 Discussion and future prospects
	5 Conclusion
	References