sharkmelley

My best guess is that you ae seeing the results of a limitation in the processing workflow, leading to posterization. Mark

That's an interesting example.  The only rings I've come across with the EOS R are in the red channel at low ISO.  But the ones above are mainly in the green channel. Is this a single exposure or ...

No, it means the Nikon D750 is using spatial filtering on the raw data to reduce the noise. It's the same spatial filtering that turns small tightly-focused stars magenta/purple on the Nikon D750, ...

Sorry, I have no experience with lenses.  My EOS R is used exclusively on telescopes. Mark

If you want to perform any kind of colorimetry then you will definitely want to use the raw files so you can use a colorimetric processing sequence.

A modified EOS R should give identical performance to the EOS Ra.  The differences seen in PhotonsToPhotos are mainly caused by the internal scaling the EOS Ra applies to the red channel.  With a ...

Probably a dust spot on the sensor.

My current recommendation is Canon because of the limitations of both Sony and Nikon full-frame mirrorless cameras. Sony has raw data filtering on longer exposures which tends to turn small tightly ...

It's a compromise. You want to remove enough of the gaps between the histograms and the left hand edge to make the background dark but if you remove too much you end up clipping data to zero.  ...

To remove light pollution you need to remove the gap between the histogram of each colour channel and left hand edge. Yes, this does also align the histograms but that is fine. Roger correctly ...

The D7500 asks for the shooting time so I'm thinking your 1200 is the total shooting time. Since your exposure times are 20 seconds that means a maximum of 60 shots (1200/20 =60). But once you ...

Yes, the blue sky is caused by the moonlight.  In the absence of moonlight the colour would be determined mainly by airglow (ionization) and light pollution. Mark

Thanks for the link to Alan Dyer's review. I wasn't previously aware that the R6 suffered from amp glow. You are most likely to detect it by stretching a long exposure dark frame (with the camera ...

No, the Hoya Red Intensifier doesn't boost red saturation. It's a badly named filter, in my opinion. As the Lonely Speck review shows, it is really a light pollution filter. Maybe there are ...

You possibly mean this: Hoya Red Intensifier Review: An Affordable Light Pollution Filter for Astrophotography – Lonely Speck It cuts out the yellow of sodium streetlights. Mark

Take a raw shot (of anything you like) with a daylight white balance. When you open it in the raw converter note the temperature/tint that the raw converter uses. You can then use that same ...

You can't edit a post to which someone has already replied.

The article you linked says that you need to use tools that subtract the light pollution.  This is best done while the data are linear . One way to do that is to use ACR to raw convert your image ...

The length of exposures you can do will very much depend on the accuracy of the tracking. Exposures of 15-20 sec should be sufficiently short to prevent the field rotation inherent in an Alt-Az ...

It's known as aperture vignetting and it's caused by the fact that off-axis the sensor sees an "almond shape" opening instead of a circular one: https://www.cloudynights.com/topic/547028-anyone-kno ...