### Relationship between nside and CAMB lmax

Posted:

**December 12 2015**For full-sky map WMAP/Planck products, 'nside' is set to nside=1024 or nside=2048. I have no problem running CAMB outputs up to lmax=2400 or so.

However, I am confused what this means when we degrade the resolution of these maps.

Let's say I degrade a map of nside=2048 (which is a map of around 50e6 pixels) to nside=16 (which is a map of 3072 total pixels). What is the maximum `lmax` at which CAMB outputs remain relevant?

Is there a rule of thumb, or a mathematical correlation here?

However, I am confused what this means when we degrade the resolution of these maps.

Let's say I degrade a map of nside=2048 (which is a map of around 50e6 pixels) to nside=16 (which is a map of 3072 total pixels). What is the maximum `lmax` at which CAMB outputs remain relevant?

Is there a rule of thumb, or a mathematical correlation here?