To clarify ... For observational Astronomy ... in a dark site. + They really need to be more specific when selling those OIII filters for Nebulars, but hey ... easy to take the $80.00
Thanks for the insight guys. Yep Yep ... you might get the other half of the story if my mate decides to jump on in. I'm well prepared for a flaming.
Sgazer ... nothing I say is ever clear ... Light Pollution sucks full stop! I do however get what your pointing towards; or at least I think I do.
Point taken on images, however for observational purposes in this case ... the OIII filter is next to useless on most targets (specified "nebular") commonly viewed in small telescopes with the one eye ball ... imo That I am being clear on. Or perhaps better said, "not for the causal user" as it will surely disappoint. I find the wording NEBULAR imprinted on the side of filter itself, somewhat misleading ... as are all things in the retail business. When he acquires a UHC or when I show him ... he will get the point ... Indeed! At least the guys at Bintel did ask me how big my scope was when I even bought a UHC ... that was nice of them!
I did try it on the crab nebua from a dark site and thought maybe I was having a case of creative thinking going on ... not sure. I do believe I was able to pull out some lines I may otherwise could not see without using it. It was a long time ago and as I am hitting on, out of many observations, I rarely got to view many targets that actually utilized it, therefore making the UHC a much more versatile piece of equipment.
As mentioned so far it's just me blowing my horn ... Or simply try the above links where I have already found it discussed ... where the opinions of others may better clarify.
As for my friends half of the story ... no comment can be given until he actually posses a UHC, and then that is when I get a New Premium tank for picking a clear winner and giving him the advice he should of first received.
I was further confused at his mention "someone told me" that the OIII was good for the flame nebular and Horse head ... again I struggle with this ... knowing just how faint such a target it. There are posts on how to better prepare in ordered to see the horse head nebular with a 12" bob ... Have a spotless mirror, use shrouds, wind protection, dew protection, pick and absolute dark site, go in good conditions and on and on ... and then someone comes up with the idea to throw a OIII over the eye piece for observational astronomy. Nar ... surely not?