Hi §AB,
You're addicted aren't you?
Seriously, great report I enjoyed it thoroughly. Pushing your 'scope (whatever the 'scope) your eyes and the conditions to the limit is a great sport that I've also enjoyed for years. This is what _serious_ deep sky observing is all about -- irrespective of what size 'scope you are looking through ; 3 or 30". This ain't touring Paris in a sight-seeing coach, it is scaling the south-face of Everest!
I too rememberr the night I broke the 14th magnitude barrier with my 10" -- and I had the same reaction. But just a quick (well, quickish) note on (faint) magnitudes.
Once you get past about 13th magnitude, it's a bit like the "Pirate's Code" -- its more like a guide, and galaxy magnitudes (generally speaking) begin to get seriously rubbery once you pass about mag 14.5.
The problem lies with (1) Most faint galaxies haven't been photometrically measured and (2) the way the magnitude is measured or calculated and at _what wavelength_.
Most galaxies etc brighter that about mag 12 have been properly (photometrically) measured at a visual wavelength to provide a proper v magnitude. When you see a magnitude number prefixed or suffixed with a "v" you know it is a proper visual magnitude. Many others for good reasons have had their magnitudes measured at a shorter blue wavelength. This is usually indicated with a (B). The general rule with these Blue magnitudes is to add about 0.75 of a magnitude to get an _approximate_ v magnitude.
Others are prefixed or suffixed with a (P) this is a photographic magnitude and many are an estimate based on its appearance on a survey plate or other image. Some are reasonable estimates some aren't.
Once you get down past mag 14.5, very, very few galaxies have had accurate photometry performed at any wavelength and the magnitude given is somtimes (often) very much a guide (in many cases a "guesstimate"). And, the problem gets more acute the fainter it is.
I've looked at quite a few galaxies with my 18" with magnitudes said to be in the 17th and 18th magnitude range -- that shouldn't be visible at all, yet they are. It is the estimate that is incorrect or rubbery.
One example is quite near the Hydra I or Abell 1060 cluster you have observed. Just 1/2 a degree NE is a small group of galaxies surrounding IC 2597. In another catalogue it is called Hickson 48. The Hickson catalog are all very compact groups of small and faint galaxies.
There is an image here:
http://stdatu.stsci.edu/cgi-bin/dss_...e&fov=NONE&v3=
From the image, the galaxies of Hickson 48 are:
IC 2597 Mag 12.8 (B) Hickson 48A (Centre)
ESO 501-59 Mag 15.0 (B) Hickson 48B (6 O'Clock)
PGC 31577 Mag 16.4 (B) Hickson 48C (2 O'Clock)
PGC 31580 Mag 17.0 ? Hickson 48D (1 O'Clock)
BTW, I _love_ Hickson groups!!
Now, IC 2597 under a dark sky will be very faint, but won't prove too much of a challenge to your 10". Surprisingly, you might also be able to see 48B in excellent conditions. Hickson 48C is visible in 31cm (and not too difficult) and using 46cm, all 4 are there. These magnitudes (B & C) are clearly (very) rubbery.
Passing on to NGC 5291, in the RC3, this has been assigned a B mag of 15.1and/or a v mag of 14.2, so you have done a truly outstanding job of pulling it in under a suburban sky. The close companion is MCG -5-33-5
which in the PGC (Principal Galaxy Catalogue) has been assigned a magnitude no less than 18! Yes 18, it isn't a typo. This is clearly, clearly wrong! I think you are right -- approx mag 14.2 to 14.3 is my guess.
That does not detract one jot from your achievement of having found and observed them -- they are very to extremely faint objects for 25cm particularly in suburban conditions -- well done!
Thought that was complicated? Now we move on to PNe magnitudes -- and that is a a _really_ complex topic (ie black art) ...
Best,
Les D
Contributing Editor
AS&T