# How to find inverse steradian from arcmin^-2 for density of galaxy

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## Summary:

I would like to calculate the relation between inverse steradian and arcmin^-2 for density of galaxy with a telescop.

## Main Question or Discussion Point

Hello,

I am using a code on EUCLID future mission. The original author of this code has set a value for the density of galaxy equal to :
ng = 354543085.80106884

I think this is expressed in inverse steradian. I think that EUCLID mission has a 30 arcmin^-2 value for density of galaxies.

Is the conversion correct betweeen 30 arcmin^-2 and 354543085.8010688 sr^-1 ?

and how to do this conversion ?

Indeed, I would like to calculate ng with a density of 48 arcmin^-2

Regards

A steradian is $(\frac{180}{\pi})^2$ square degrees, and a square degree is 60x60 = 3600 arcminutes^2. So a steradian is 11.82E6 arcminutes^2