CanA tube 

Helical Index practice #1

Power spectrum dimension: 4096 x 4096 pixel,
1.08 Å/px. Method (spider, old method)

CanA tube rmax and rmin: 152Å and 75Å

Power spectrum can be inspected using EMAN2:
e2display.py

Download Power spectrum

Checkpoint

which two layer-lines (LL) were used? 

Note, there may be multiple acceptable answers to this question.  Format: LL (R, Z)
LL (17, 97)
LL (157, 87)

What are the possible Bessel order ranges for those two vectors?

LL (17, 97):
       2*π*R*rmax = 2 * 3.14 * (17/4096/1.08) * 152 = 3.67                     Bessel order n ≤ 2
       2*π*R*rmin = 2 * 3.14 * (17/4096/1.08) * 75 = 1.81                         Bessel order n ≥ 1

LL (157, 87):
       2*π*R*rmax = 2 * 3.14 * (157/4096/1.08) * 152 = 33.9                    Bessel order n ≤ 32
       2*π*R*rmin = 2 * 3.14 * (157/4096/1.08) * 75 = 16.7                       Bessel order n ≥ 18

What are the possible symmetries?

What's the correct symmetry (quickly check whether it is in your list)

point group: C1
helical rise: 1.58Å
helical twist: -173.7. degrees

Positions of Bessel function maxima

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