The purpose of this note is to determine the maximum level of polarimetric noise that can be tolerated when performing filter polarimetry of the He I lines at 5876°A and 10830°A. The objective is to ensure that their Stokes parameters still carry enough information for an acceptable magnetic inve... Show moreThe purpose of this note is to determine the maximum level of polarimetric noise that can be tolerated when performing filter polarimetry of the He I lines at 5876°A and 10830°A. The objective is to ensure that their Stokes parameters still carry enough information for an acceptable magnetic inversion. Show less