Naked eye magnitude limit

[Lester]

G'day All,

A few have asked me, what is the seeing like at my place. Sunday night after the Moon set I put it to the test. I could pick out one lone star within the Coal Sack Nebula=SAO252046 Magnitude 6.5 . I could see it all the time with direct vision.

No doubt others with younger eyes, higher elevation or a cold winters morning will be able to exceed 6.5 .

I will be interested to hear your results.

[asimov (John)]

Seeing as I'm only about 10-15 K's south of you, my skies are roughly the same as yours at a guess.

[janoskiss (Steve H)]

You guys are very lucky!

[Stu]

Last month, 200k's north of perth I could see to 6.44mag
Last weekend, near Gundagi (NSW) it was off the chart, so I can't give an exact figure but approx 7.
Haven't tried measuring from home (Seaford, VIC) yet. I'll make a guess at 4.5 to 5.0, I'll try it tonight if it's clear.

[JohnG (John)]

If any of you use the free program, Cartes du Ceil, here is an add-on that draws a triangle on the star map and gives you the magnitude of stars inside, allows you to get accurate magnitude estimates. Scroll down to Finnish Triangles, download and install, it is weighted slightly to the Northern Hemishere but I have found it useful here.

http://wgg.com/scope/cdc.html

JohnG

[mickoking]

Here in good old Gosnells (suburban Perth) I can see mag 5-5.5 depending on conditions, light pollution etc etc. In 2003 when I went to Tibet I was at Everest Base Camp with an altitude of 5200 M and I swear I could see well below magnitude 7, I have never seen such a dark sky. There were so many stars that even finding Orion was a hassle. However, I wish I tried to look for Barnards loop, apparently its visable in the very darkest of skies

[Blue Skies (Jacquie)]

Not having the best summer here, but then summer is never the best conditions for seeing.

If you are serious about determining limiting mag go to the International Meteor Orginisation site and get the tables. http://www.imo.net/visual/major/observation/lm

The best I've ever seen was off the scales and at least 7.6 I was out in the wheatbelt in May for that one. Also remember a memorable night in early August when Hale-Bopp was around. I've also heard of a realiable observer reporting 8.0 from altitude at Machu Picchu in the Andes!

[fringe_dweller]

Gday Lester,
I know you said/specified what mag star could easily be held in your view, but if you mention your NELM or LM to say to another AA but versed international AA, and dont specify otherwise (ie. 'the LM near object was..', or ' the LM through the 'scope is ..' ect.) like you did, they would most probably assume you mean the Zenith Limiting Magnitude - which means the faintest possible star you can see in the very small section of the sky straight up at zenith - even if it only blinks into view for a millisecond at a time, and if it means having to squint so hard that tears start to run down your face to see it after half an hour of looking [I joke?]- and all this on the best clearest darkest night possible
That is your site's Naked Eye Limiting Magnitude or Limiting Magnitude, except if your specifying a particular event/night and conditions connected with it - the other AA will know that means that no need for modesty in this area - just the facts! sorry!
even close to Adelaide I can squeeze out a 7.2 at zenith fairly often :-)
cheers

[fringe_dweller]

Originally Posted by mickoking

There were so many stars that even finding Orion was a hassle.

I have seen it like that a few times here in SA - even was prolly below sea level on one occasion (not that I get out to the country very often at all) we do quite often get very nice transparency here in countryside of SA, and sometimes extreme transparency.
It is an eye opener when you see it tho eh - and it hurts your eye's to look at the stars, after dark adaption, you know your somewhere very dark indeed. Not easily forgotten be extra nice with amazing scenery/location like that thrown in :-))

[OneOfOne (Trevor)]

From my back yard, some nights I can see FIVE stars in Crux....not the usual 4...is that good?


Or do you think I need to kill some of the neighbours lights, the three footy ovals, the glow from Melbourne. At least I can read the newspaper some nights while waiting for the scope to slew.

If if didn't take so long to get to work, should I consider moving to the Nullabor!
Enjoy living on the Dark Side while you can, the lights are coming!

[Lester]

Thanks for your replies, no doubt there will be more.

Some fantastic views you chaps have reported

Yep I'll be trying at the zenith.

[ausastronomer (John Bambury)]

I spent 5 weeks touring New Zealand in January, 2005 with my wife who happens to be a Kiwi. I took my 16 x 60 Pentax Binos with me. We spent about 14 days on the West Coast of the South Island from Te Anau up to Greymouth. The section from Haast up to the Glaciers at Fox and Franz Joseph were as good a skies as I have seen. The transparency was superb as the prevailing breeze is a westerly off the Tasman Sea with the mountains right behind you. The seeing wasn't great but that didnt matter much as I was only using binos. I didn't attempt an accurate LM test but it was well over 7.0. NGC 2808 a 6.2 mag glob in Carina was a pretty easy naked eye target.

CS-John B