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PEC Analysis

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#1 Phil Hosey

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Posted 08 August 2009 - 05:41 PM

Hey guys,
I'm trying to measure the PE of my Atlas using PHD and PECPrep and want to make sure I'm doing this right. I setup PHD to output a log file and told it not to send guiding corrections to the mount. I let it record 2 worm cycles, about 16 minutes in the case of the Atlas, which was about all I could get before PHD lost the star due to I assume Dec. drift. I then imported the log file into PECPrep and gave it the focal length of my guidescope (434mm), pixel size (5.2um) and 1x1 binning. Assuming this is all correct, PECprep is telling me I have roughly 13-15 arcseconds P-P of PE. What I'm not sure about is if I'm using the correct value for binning because I'm not sure where this comes from.

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#2 Tim C

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Posted 08 August 2009 - 07:36 PM

Hi Phil - what kind of camera did you use to capture the data? That may be needed so someone can answer your question. BTW, I've tried several times to import log data into PECPrep and always get some sort of error. Did you do anything special to the log file first before you successfully imported it? I wound up converting mine to excel and creating my on PE curve in excel.

#3 Rusty

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Posted 08 August 2009 - 08:24 PM

Hopefully, others will chime in, but I'd be tempted to use 2x2 binning for a DSLR, since it uses a Bayer matrix that's 2x2 (R, B, Gx2)

#4 Phil Hosey

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Posted 08 August 2009 - 09:21 PM

Guys,
I'm sorry, I totally forgot to mention the camera. The data was aquired with the Orion Starshoot Autoguider. The only info I have on it is that it 1280x1024 pixels at 5.2um. My guidscope's FL is 434mm. These are the parameters I used when importing the PHD log. I did not have to do anything to the log, it imported just fine. The only thing I don't know is if the camera is using any binning, I can't seem to find this anywhere in the documentation for the camera or in the software settings for PHD.

#5 jrcrilly

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Posted 08 August 2009 - 09:36 PM

The only thing I don't know is if the camera is using any binning,


You can tell by the image output. If it's 1280X1024 then it's not binned. If it's 640X512 then it's binned 2X2 and so forth.

#6 blueman

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Posted 09 August 2009 - 01:47 AM

What you have done gives you a fair representation of the PE of the mount. You should also go into the frequency pannel and see how that looks to determine where the errors are and if PEC can help to correct them.
Blueman






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