I'm sure William Herschell might've appreciated not having to build a forty foot monster, had he had a barlow..
similarly anyone with a scope of reasonable aperture but shorter focal length might benefit from a barlow, at considerably less expense than the price of a larger scope.
there's image-scale, as mentioned... there's using an EP of wider fov and fieldstop than a shorter focal length EP... for the same magnification.
...the televised world stopped to watch dim grainy Apollo pictures... and since, no such airtime but for the two Shuttle disasters has been so eye-grabbing .. that 'barlowed' view way back then can't compete with the big bright splashy expectations now....
the energy and enthusiasm of unjaded youth has yielded to the artery-clogged mentality of geriatric Porsche's unable to merge with the traffic...
it might not be the barlow letting down your expectations.. it might be that 12" - 24" that you've outgrown... the sheer joy of reaching out to the cosmos might now be the "Ho Hum" of wearing last year's fashion..
I wouldn't say a barlow is a "must have", but I get plenty out of mine.
I also like the views through my 70mm refractor, barlowed sometimes, and all the rest that I have at my disposal... affording me many views in many ways. Sometimes I even forego aperture and magnification to look with my bare eyes!
...some people prefer bicoculars! it's a crazy world, I know.. but hey,
let them barlow who would not tresspass against us... as we would not Retchie Chriten against them, ..ok?
