Raw Data
Feel free to download the images and try for yourself!
Averaged Spectrum
And we can identify Paolo once again ;-)
Dark Frame Technique vs Plasma TV
A plasma TV creates some more or less static lines, like hot pixels in a long exposure CCD camera. The dark frame technique subtracts the "ideal" hot pixel map, or TV lines, in our case. A dark frame is created the same way as the averaged spectum. In the case of a CCD camera, one simply puts the lid on the objective lens. For TV, life is more complicated. To create a dark frame, I selected spectra were the TV lines were essentially the only signals present. Maybe, in a second step, one may want to try to capture spectra of the particular noise source with an insensitive antenna close by...
That would be my dark frame for tonight (5 selected spectra averaged):
With dark fram "opacity" set to 30%, that's what the little averaging program comes up with:
DF opacity set to 100%, pixel values of less than 160 are set to 0.
Dark Frame Technique vs OTHR
Yep, this technique is suitable for getting rid of radar stuff too. To me, it seems more to help aesthetics than anything else... but... you never know.
Last night, nice radar spectra were recorded. A couple of those resulted in the following radar "dark frame":
Earlier today, that was recorded... (averaged)
Averaged using the dark frame:
Conclusion
Those are my first steps using my experience in imaging gather in long-exposure webcam deep sky photography. I am in a very early stage using said techniques in QRSS imaging. My impression is,
imaging techniques used in astrophotography can help QRSS. Those techniques can even help fighting local QRM. A lot more learning is required... I remember my learning curve in astro-stuff... my first astro-images totally sucked!
