Using the formula:
[value in cd/m2]	=	10.8×104 × 10(-0.4*[value in mag/arcsec2])
OpenOffice formula:	=108000*POWER(10;(-0.4*mags))
MS-Excel formula:	=108000*POWER(10,(-0.4*mags))
	Where mags is the cellname that contains the mag/arcsec2 reading.