Light pollution reduction filters increase contrast of astronomical images taken in light polluted urban skies. I've been tempted to try one for a while, but the cost can be quite steep running from about a hundred dollars to several hundred. I recently received a gift of an ICE LiPo Light Pollution filter that fits my new Sony RX100V camera. ICE optical glass filters are made by Desmond Photographic with offices in Oregon. Their products can be found at B&H, Amazon, and eBay.

I've been unable to find any reviews or specifications for the filter beyond the description: Reduces ligh pollution for crystal Clear Night Skies, Blocks out skyglow without changing the entire color spectrum, optical glass filter. They are made in 1.25" eyepiece, 48 (2" eyepiece), 49, 52, 58, 62, and 67 mm sizes. Reviews I found of other products that they distribute were positive and their prices are very low, a fraction of other light pollution filter alternatives.

The two comparison images below are straight out of the camera other than format conversion and resizing. They link to full size images. The sky was moonless and relatively dark with thin clouds. The comparison exposures with the Sony RX100V were taken at ISO 400, f/2,with a 24mm (equiv) focal length for 20 seconds. First the image without the LiPo filter:

Next with the ICE LiPo filter with camera settings unchanged:

I'm very pleased with the results. I may be able to do a bit better with a premium filter, but the ICE LiPo filter gives outstanding results for a very low cost. The test setup is shown below with a Vixen Polarie tracker:

I took a lot of other data to help me zero in on the highest dynamic range ISO gain to use with the camera and also shots with the lens zoomed in to its maximum 72mm equivalent focal length. The image below is a work in progress, a Nebulosity stack of 30 20 second ISO 800 images for a closer look at Orion.

A 1:1 pixel crop of the Orion Nebula, M42, in the image above:

For a similar image with an hour of total exposure time taken the next night see: