[3dem] How to calculate tilt angles in Saxton acquisition scheme?

Philip Koeck Philip.Koeck at ki.se
Fri Mar 31 04:31:21 PDT 2017

I’m guessing it should be alpha_n+1 = alpha_n + arcsin(sin(alpha_0)*cos(alpha_n))

Simple typo.

However I don’t know for certain!
Maybe you can find the above formula in the original paper.


Från: 3dem [mailto:3dem-bounces at ncmir.ucsd.edu] För Charlotte Hamngren Blomqvist
Skickat: den 31 mars 2017 11:22
Till: 3dem at ncmir.ucsd.edu
Ämne: [3dem] How to calculate tilt angles in Saxton acquisition scheme?

Dear all,
I am currently trying to print out all the tilt angles in a tilt series using the Saxton scheme. I find the reference Saxton 1984 unsatisfactory in how to actually calculate the values. Also, in “Electron tomography”, edited by J. Frank p. 143, it says:
“In this [Saxton] scheme, the tilt angle varies as alpha_n+1 = alpha_n + arcsin(sin(alpha_0)*cos(alpha_0)).“
As I interpret this expression, the last term on the right-hand side is a constant, and hence the tilt angles are distributed with an even angular increment throughout the series. This should not be constant!

Please, can anyone shed some light on this? What am I missing here?
Best regards,
Charlotte Hamngren Blomqvist

Charlotte Hamngren Blomqvist, PhD

Department of Physics
Eva Olsson group
Chalmers University of Technology
SE-41296 Gothenburg, Sweden
Tel +46-(0)31 772 51 80
E-mail: charlotte.hamngren.blomqvist at chalmers.se

Visiting address: Fysikgränd 3, room F4417b


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