[§AB]

Originally Posted by ngcles

Hi §AB,

Congratulations on your big night! You certainly made up for lost time with the cloud.

thankyou Les! It was one of the best sessions i've ever had, despite the seeing. Everything just went perfectly!

Excellent observations -- paints a good picture of what was seen and what it looked like. Good to see you looked at NGC 134. Did you see NGC 131 nearby?

Ah yes I did see NGC 131, but forgot to report it. It was easy at 217x (my increasingly favourite galaxy hunting mag), appearing as a slightly elongated glow. NGCIC.org has it at mag 13.1.

First up here are my observations of the IC 4765 group made in July 2000 with 31cm from our nearly dark site in the southern highlands. I noted the transparency was 8 and seeing 7. I have no independent recollection of the night or the galaxy group so I can only conclude the ZLM was about the 6.2 - 6.3 mark.

x186 36' TF. IC 4765, IC 4769 and PGC 62391 are in the same field, ESO 104-7 is also there.

IC 4765 Mag 12.3p Size 3.4' x 1.8'. Obvious but not large, perhaps 1.5-1.75' diameter. Typical elliptical profile rising moderately and broadly to the centre azonally without any obvious nucleus. Possible slight elongation in PA 135. In PA 300 4' distant is a tiny glow -PGC 62391. IC 4769 is is 11' N and ESO 104-7 is 2' S.

PGC 62391 Mag ?? Size ?? 4' W of IC 4765, perhaps 30" diameter rising moderately and evenly to the centre. very faint * embedded in the halo or just to the N off halo.

IC 4769 Mag 14.1p Size 1.9' x 1.1'.Found 11' N of IC 4765, very LSB, 50" x 15", lengthened form of gossamer rising slightly to the axis and centre.

ESO 104-7 (PGC 62408) Mag 12.9v Size 1.6' x 0.8'. Moderately faint only 2' S of IC 4765. not particularly difficult, 50" x 30" in PA 90. Brightens moderately to the centre without discernable core or nucleus.

So it seems you saw IC 4766 when I seem to have missed it, but I recorded the other two PGC/ESO galaxies in pretty much the same way you did with the exception of a faint star I saw in the halo of -91.

yup IC 4766 was definatelly there, but was very difficult and required intense concentration and averted vision to spot.

§AB wrote "This star is located just north of a 12th mag pair. I could *just* detect this star, and so I jotted it down in my notes. I did a bit of sluething this morning was almost fell off my chair when I found it is magnitude 15.95!!!!!! IS THIS POSSIBLE!!?!"

Certainly. But an excellent accomplishment in what I take were outer suburban conditions. What was the ZLM (NELM) ?

My eyesight is pretty crap (near-sightedness+astigmatism), but I'd say it would be in the 5.0-5.5 range (I can see all stars in Copernicus). But both my parents have developed far-sightedness, my grnadma is short sighted; so could be genetic, and/or my long hours of staring at computer screens at uni!

As for limiting magnitude with a 12". Well that depends on a lot of things. Experience, optics, conditions, elevation and perhaps most importantly time spent at the eyepiece.

A good 8 years under my belt since I got my 4.5" reflector and really got into deep sky hunting

I see you said "I spent about an hour picking off objects in this cluster." and that is probably what made the difference between detecting these very faint stars and not seeing them.

You're right, the 15.95 mag (very almost 16!!!!) star only started popping in and out of view after several minutes.

I know the faintest stars in my 12" seen were a bit worse than true v magnitude 16. About 16.3 I think from memory, but I frequently saw mid 15s if I went looking for them, concentrated and spent just a little time to detect them.

So my sightning is entirely plausable then, that being a mag 15.95 star from 5.0-5.5 skies. I wasn't dreaming then!

It all depends up how much time you are willing to spend. It also depends on what you call "seen". In the pursuit of extremely faint objects, some observers will call it detected if seen two or three times
over maybe 20 mins. Others (like me) find it hard to be that patient! I will sometimes spend 15 or 20 minutes trying to detect extremely faint extended objects but generally not stars (at least not on purpose).

I'm probably more like you, I'll concentrate at my hardest and use full on averted vision in an attempt to spot a faint target within several minutes, If i don't see anything within 30 minutes I'll call it a no sightning. However, if I see 'something' once or twice, I'll call it 'suspected'; and if I catch regular glimpses, I'll call it confirmed. Faint stars are fun to chase, just to see how "low you can go!" Now that I've captured a mag 15.95 star, I'd say many Quasars are within my reach, yes?

If you are prepared to become ultra dark adapted, go to a true pristine site at elevation and spend about an hour at the eyepiece to get two or three glimpses of a faint mote, then low 16s or even 17th v magnitude (stellar -- not extended) isn't entirely out of the question for 12". It also depends on the age, experience and acuity of the observer.

That'll be cool, but are there any deserted areas in the hills where one could setup and not see a single car or person the whole night? Like say lake shores, carparks and river banks - they are normally public land...

For the rest of us, assuming a reasonably experienced observer, good conditions at sea-level, its probably about the faint end of 15s seeing regular though occasional glimpses of the star with AV.

Great report mate -- a ripper!

Yup that pretty much describes my 15.95 mag star - just glimpses. A couple of neighbouring 15.5 and 15.7 stars were held in vision pretty much constantly.

Once again thank you for your comprehensive reply Les.

Clear skies to you!
Sab.