The first image above was taken in 2010, whilst the second imagine was taken in 2019. However note
the colour cast of the first image compared to the second. In order to understand why the difference
I have listed the difference in the two exposures.
The first Image was taken in my back yard using a CCD-CLS filter to remove the light pollution. The camera used was a Canon 20D with the LPF removed.
The second Imagine was taken under dark skies with NO CLS filter. The camera was a Canon 40D with the LPF removed..
I don't know if the colour tint in the first image is due to the CLS filter light pollution combination or due to my processing difference
for the two images. I may have to revisit the data of the first
image to understand why.