It appears that the Orion Mars Observation has a similar filter curve as the DGM GCE filter:
Would the Orion filter work as a 'poor mans' galaxy filter? It's cheaper and seems like it does almost the same thing.
Looks like it would work, and better than the #8 filter. It seems to cut out more light, in a wider swathe than the DGO GCE or Orion's Moon and Sky Glow Filter. On the other hand, the DGO GCE might make a really good Mars filter. It might be worth saving a few more nickels and buying the better filter.
Never trie Orion Mars filter on galaxies, or DGM GCE filter on Mars yet. But now I will have to do it sometime.
P.S. Skyglow works really good on Jupiter to being out bands, red spot, and polar caps.