High ADU-Value of Biasframes when opened in PI

[christiank]

Hello!

I acquired a set of Bias, Dark an Flats for the basic ccd parameter script. After opening in PI Darks and Flats have the normal range of ~500 in Darks and ~25000 in Flats. But the Biasframes have a strange value of 33000 in PI. Also the histogramm shows this.  Astroart and Fitswork show the Bias correctly with ~490. The frames were taken in one session with Astroart with range 0-65535 linear in .fit.  Bias with Exposuretime "0".
After loading some older Biasframes, PI shows the same behaviour. They have all a value of about 33000. No stretch or processing was done. Files were only opened.
I changed the exposuretime to "1" second in the Fitsheader. But there was no change. Value 33000. 
What is the problem here?

[Juan Conejero]

What is the problem here?

Typical FITS interoperability issue. The bias frames, despite the fact you have selected an unsigned 16-bit integer range, have been stored as signed 16-bit images where only the positive half of the numeric range is being used (and hence they are actually 15-bit images).

Open the Format Explorer window, double click the FITS item on the left panel, and make sure the signed integer images store physical pixel data option is checked, then click OK. This option is always enabled by default, so this problem should not happen. Which version of PixInsight are you running?

[christiank]

Thank you Juan!
The box was not checkd. It works! 
I run the latest version of PI. Updated 4 weeks ago.
And OT: this version runs very good on my system win7pro/8core amd/16gb ram. The older versions didn´t. So at last PI and me could become friends