Hi Smirnoff, Enchilada & All,
Smirnoff, your observation of NGC 4071 is broadly consistent with my one and only recorded observation of it back in 1999 with 25cm from suburban Engadine with a ZLM of about mag +5.1:
x181 17' TF. Mag 13.0 Size 80". This is a very LSB and fairly faint PNe for these conditions Only 45 degrees elevation. Appears in a field which is littered with faint *s. To the NE by 7' is a mag 9*. Appears basically as a translucent disc with an indefinite central hole. Using A.V it occasionally seems annular. In the SW corner of the halo it seems there is an enhancement in the form of a slightly brighter curved streak tracing inside the outline of the outer halo. This enhancement is only slightly brighter than the balance. 90"-100" diameter. No central * visible. Not seen without the filter.
NB the filter was a Lumicon UHC (narrowband) which passes both doubly ionised Oxygen and Hydrogen-Beta lines. I'm trying to remember who put me on to this one
because it is rarely found in most of the main-stream atlases. From memory, I
believe it is the faintest integrated magnitude PNe in the whole NGC (please correct me if you know better) -- not absolutely certain on that one.
There is an image of it taken by Steve Quirk with 31cm and a G-star camera here:
http://my.hwy.com.au/~sjquirk/images/gstar/ngc4071.html
Is this the one you were speaking of Enchilada ??
As for IC 4191, this was my impression with 25cm in 1998 from suburban Engadine with a ZLM about +5.0:
x138 21' TF + x276 10' TF. Mag 10.7 Size 5". Very difficult to distinguish from a *. Follow Hartung's directions. 9' N of a mag 6 deep orange *. Quite minute, < 5". Forms a RA Tri with a couple of *s to the S and E. Disc surrounded by a tiny amount of LSB haze or could be sky haze??. Disc brightens to centre. No central *. Circular. Turquoise without filtration.
Must go back soon and re-observe all three with larger aperture and a variety of filters -- in a month or so hopefully.
Hope this helps.
Best,
Les D