# 1029-mask small scale structure

<figure><img src="https://689908955-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F4sTZMNzV0yZYrZxJZ9AZ%2Fuploads%2FQEzNi0n0914i0YivBEob%2Fmask.jpg?alt=media&#x26;token=ae3cd0ca-4307-4981-84b7-4936e104904c" alt=""><figcaption><p>mask itself</p></figcaption></figure>

showing the raising power spectrum when estimate on no-convolved map is from the coupling between mask and beam.

<figure><img src="https://689908955-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F4sTZMNzV0yZYrZxJZ9AZ%2Fuploads%2FwhG4GvhQzQu6WXsXG3DO%2Fcf_mask.jpg?alt=media&#x26;token=71572426-e8a2-4299-bbad-6138f4237e51" alt=""><figcaption><p>cmb + diffuse fg</p></figcaption></figure>

when l>400, relative error begin to exceed 5%

<figure><img src="https://689908955-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F4sTZMNzV0yZYrZxJZ9AZ%2Fuploads%2F1a8ElOd9mhBzhniMPbBv%2Fpcfn_mask.jpg?alt=media&#x26;token=060017b0-94e0-4aa3-814e-caa478b08dcd" alt=""><figcaption><p>PS + FG + NOISE + CMB</p></figcaption></figure>

showing it is hard to deconvolve map with point sources the do power spectrum estimation.
