[3dem] CTF Correction with Spider

[xim9 at pitt.edu]

Dear All,

I use the software, SPIDER to correct CTF. In order to compute the phase
contrast transfer function (Spider operations, TF C or TF C3), GAUSSIAN
ENVELOPE HALFWIDTH need to be known. I have two questions about it.

(1) what is the range of Gaussian envelope halfwidth for FEG TEM?
(2) how to estimate this value?

Does anybody Know this?

Thanks,

Xin Meng