sharkmelley

I have no information on the X-T200 Mark

So you're using DSS median kappa sigma clipping.  This does actually calculate average values in each pixel but extreme values (those outside the kappa sigma clipping threshold) are replaced by ...

You should not use the median but use the average instead.  Using median combination on a bias frames will usually result in a constant value everywhere. In fact, don't use median anywhere, ever. Mark

What exactly are you feeding into DSS?  Have they been pre-processed? If you are loading raw frames into DSS then I don't understand what you are seeing. If you are loading processed bias and dark ...

It actually is tilt-shift photography.  The blurb claims he 3D printed a tilted adaptor. I was doubtful so I measured the background noise in the image on his own website and it is identical in all ...

Yes it is still there but I believe it is only applied to bulb mode exposures on the A6000 and A6100, just like on the Sony A7S.  It's the reason I shoot manual 30sec exposures on my Sony A7S. Mark

The raw data filtering (aka star eater) on the A7Riv is applied to all exposures of 3.2sec and more. It will affect small tightly-focused unsaturated stars that have no trailing.  The effect of ...

Tilt-shift astrophotography - whatever next!? Mark

If we take the Sony algorithm for example, every 3x3 (same-colour) neighbourhood tends to have a pixel brighter than the others. This pixel will then have its value suppressed. Yes, that's a lot ...

Wow! That is precisely the G-channel auto-correlation you find if you examine a file affected by v2 of Sony's raw data filtering, the so-called star eater. V1 of the algorithm was applied to the ...

To counteract the confused thinking in that article, here's a simulation I performed: Star with its star trail and a gap The point spread function (PSF) of the "star" in the diagram is a Gaussian ...

It's being wrongly described above as a median filter. A typical hot-pixel-suppression algorithm works in 2 stages: (1) Identify extreme values (2) Replace those extreme values ...

One of the FujiFilm cameras (I forget which one) replaces the values of outliers with the median value of its neighbours.  So solitary bright or dark pixels still exist and it does not have the ...

A star has a circular point-spread-function. So with a short interval between two successive exposures, the end of one trail will overlap the start of the next one. So there is actually no distinct ...

You need a combination of longer exposures (e.g. using an intervalometer) and shorter gaps between exposures. Maybe a faster memory card would help to reduce the gaps? Mark

I'm not convinced by that "explanation" for the rounded ends of each section of star trail. No wonder the author has failed to find a similar idea elsewhere on the internet. The image of a star ...

Beautiful result.  I love all that dust! Mark

On which criteria do you consider it to be the best? Are those criteria relevant for astrophotography? Mark

Are you suggesting a blur convolution matrix is applied to the data? If so, I'm unconvinced because this would have the effect of smearing out image details. I think what we are seeing is more ...

Yes it's possible - see here for example: https://www.astrobin.com/full/327930/0/?nc=user Mark