Signal to Noise Ratio Calculation According to : Detecting and measuring faint point sources with a CCD (Herbert Raab)
Telescope data
1	Mirror diameter	0.305 m		D
2	Obstruction	0.10 m		O
3	Ligth collecting area	0.063 m^2		(p . D^2 - p . O^2)/4
4	Focal ratio	4
5	Focal lenght	1.22 m
Detector (MX716)
6	Pixel size	17.2 mm		Binning 2x2
7	Píxel scale	2.7 ²/pixel
8	Dark current	0.1 e^-/s/pixel
9	Readout noise	12 e^-/pixel
10	Quantum efficiency	65%
11	Integration time	100 s	600 s	T
12	FWHM	4²
Object and Sky
13	Object magnitude	19	20
14	Object flux	6927 g	16625 g	4 . 10^10/2.5^mg/sec/m^2 . t sec . 0.063 m^2
15	Object signal	4502 e^-	10806 e^-	(14)*(10)
16	Share for central pixel	.29	.29	Function of FWHM
17	Object signal in central pixel	1306 e^-	3134 e^-	(15)*(16)
18	Object Noise in central pixel	36 e^-	56 e^-	SQRT(17)
19	Sky background	18 mag/”^2	18 mag/”^2	Brightness per squared arc second
20	Sky back. Flux	126243 g/pixel	757459 g/pixel	4 .10^10/2.5^mg/sec/ m2/² ^2 . (11) . (3). (7)^2
21	Sky back. signal	82058 e^-/pixel	429348 e^-/pixel	Flux . quantum efficiency
22	Sky back. noise	286 e^-/pixel	702 e^-/pixel
23	Dark current	10 e^-/pixel	60 e^-/pixel
24	Dark noise	3.2 e^-	7.7 e^-
25	Noise in central pixel	288 e^-	704 e^-	SQRT((18)^2+(22)^2+(24)^2+(9)^2)
26	Peak SNR	4.55	4.45	(17)/(25)