Light pollution: Same object, same duration, same temperature, DIFFERENT SITE

[MikeWilson]

Hi all,

I thought it might be interesting to compare the differences in light pollution between two different sites where conditions were approximately the same.

Relative humidity in the first image was around 80-85% and in the second image, around 90-95%.

Both images were taken at 13C.

The first from my cruddy local skies on the 21st, and the second from slightly murky (due to humidity) but dark skies at Butser Ancient Farm.

Identical equipment and near-identical conditions - unprocessed

Home

Butser Ancient Farm "Dark Site"

[MikeWilson]

On both images:

Noels Actions:

Light Pollution Removal (radius max, threshold 3)

Enhance DSO and reduce stars

2x Local contrast enhancement

Single simple run of the Noise Ninja filter

Home

Butser Ancient Farm "Dark Site"

In summary: I am absolutely shocked at quite how much sky conditions can affect the quality of one's images. I want to identify to what degree the quality of the sky affects the required integration time as I expect that by stacking a larger number of the light polluted frames that it would be possible to get the equivalent of a single frame from darker skies.

(These galaxies resided in the most light polluted part of the sky at the dark site).

I suspect that by imaging at home under severely light polluted skies that I am fighting an uphill battle. As a rough estimate, I would say at the moment that an hour's worth of integration time at home is roughly equivalent to around fifteen minutes at the dark site, ergo meaning that time spent imaging at the dark site is roughly 200-400% more effective (by contrast) than at home.

The quality of the sky makes all the difference in the world.

[RikM]

I couldn't agree more Mike. The M81 and M82 I shot I SGL6 was a world away from what I can manage from home even though the skies are not too dissimilar. Fuel for the car to go somewhere dark is the best purchase you can make for astronomy.