Attempt at a Clear Sky Filter comparison

[Lee_P]

Hi everyone,

I bought a Clear Sky Filter (http://www.bristolcameras.co.uk/p-skywatcher-clear-sky-filter-1-25-inch.htm) in the hope that it would help cut through the horrendous light pollution I live under. I've tried to make a fair comparison of photos taken with and without.

This was a lot more difficult than I thought because it's not possible to just change one variable (with filter, without filter); the filter blocks so much light that exposure times need to be five times longer. I settled on making the total stacked exposure time the same (5 minutes). Anyway, I did the best I could and the result is attached. I honestly don't think there's much in it, and may even prefer the version without. It's also easier to take photos without the filter...

Your help is needed! How could I improve the test? Which do you prefer? Are these targets (M81 and M82) not particularly suited to the filter? What do you think?

[Astro Imp]

Having looked closely at the stacked and edited images I agree that there is not a lot of difference.

FWIW M81 seems slightly brighter with no filter and M82 appears to show slightly more detail with the filter.

The only thing you might like to consider is using different types of objects. Other than that I leave it to more experienced members to comment.  

[Lee_P]

Yep, I wonder if a difference would be easier to see in planetary nebulae, for example.