ctftilt-problem with tangle readings
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Hi Niko
I'm a PhD working with Corinne Smith at Warwick.
I have been using ctftilt for a while now but have run into a problem with a new tilt series. This series was recorded at 57252x mag (with 1.43x correction due to the CCD position) at ~42 degrees tilt (as far as we can go) using the following parameters:
1.4,200.0,0.15,57252,15.0,1
128,200.0,5.0,5000.0,30000.0,1000.0
The images are 4096x4096 TIFF format converted MRC images (converted using tif2mrc).
The readings for TANGLE vary wildly across the series with some negative and others positive and only a few close to the recorded tilt angle. I assume TANGLE should be very close to 42 in this case.
For a previous series all these values were around -47.0 using these parameters:
1.4,200.0,0.19,40000,15.0,1
200,200.0,10.0,1000.0,50000.0,1000.0
I have tried using these parameters on the new series but still many of the TANGLE readings are still out.
Also I saw on a previous post something about Tilt(A) and Tilt(R) parameters to limit the tilt angle checked but don't see where to enter these in ctftilt. Would these parameters help?
Any help would be very much appreciated.
Sorry for the long post.
You should be able to provide
You should be able to provide an expected tilt angle (TiltA) and tolerance (TiltR) as the last two parameters on the second input line. In your case, this would look something like this:
The two additional parameters were added recently (within the last year) so you should make sure you have the latest version of ctftilt. Providing an approximate tilt angle will help greatly in finding the correct tilt angle.