Re: M27 and filters: It's the colors, Dumbbell!
It might be illuminating (pardon me) to look at the moon in full daylight, using a telescope/eyepiece combination that produces an exit pupil the same diameter as the pupil of your eye in daylight. Keep both eyes open and do not use an eyepiece cup. See whether the moon's sunlit surface looks dark or bright then.
Some DSOs of course show noticeable color when viewed through a telescope. Among those are the Ring Nebula, the Orion Nebula, and the Triffid Nebula. For the latter, ask viewers whether the two lobes show color. (Typical reaction: "No...") Then ask if the two lobes are the same color. (Typical reaction: "Ohhhhh...!")
-- Jay Reynolds Freeman
http://JayReynoldsFreeman.com (personal web site)