Pickup SRA - starting from a 500x microscope

I agree Smoffatt, it definitely takes a lot of practice. I don't particularly like the Dinolite software.

One can use the following for a trial and see what they they think:

1. Pixelstix - this is great software (< $5) to get the baseline at 180 degrees. This is critical of course for SRA calcualtions. Its very difficult to sometimes get the camera adjusted so the base of the platter is exactly at 180 degrees. You get better and better with practice, but it helps to have a program that corrects the image to 180 degrees.

2. ImageJ - free and very accurate to drawing and calculatiing angles to the hundreth decimal point. Using ImageJ and taking the average of a few measurements will give you a very accurate reading.

Good thread at Audioshark.org with comments and pics of SRA. To see the pics you have to log in.

http://audioshark.org/all-things-analog-21/your-own-sra-pictures-6404-page2.html

Thanks for this Phil. Can you calculate angles with Pixelstix as well or do you just import your image into Pixelstix, correct the image to 180 degrees and then move it to ImageJ to calculate the angles? I will download ImageJ.

Indeed, for me getting a perfect 180 degree image to start with is very difficult.

Thanks for the link too.
Sly

One problem I can think of with using the trusted ear method of determining the proper angle, any of the angles involved, is that you never know when you have achieved a local minimum, in terms of distortion. That is why a technical method should yield better results. Analogous to trying to determine the ideal best sounding speaker locations by ear. Technical solutions should yield better results than ye olde move a little, listen a little method.

SMoffat - You can use Pixelstix for both horizontal and angle calculation. Sorry I should have mentioned this sooner is another good 'horizontal' calculation program is Go Horizontal. Its costs less than $5 too and is even more simple to use.

I would go with Go Horizontal for the 180, and then ImageJ for the angle calculation. Pixelstix combines both but is more complicated to use.