MSNBC does it again !
MAT
"The smash-up between galaxies M86 and NGC4438 not been suspected before,
and may explain why M86, which is visible to the naked eye, is unable to
give birth to new stars."
http://www.msnbc.msn.com/id/27101177/
Chris L Peterson
>M86 visible to the naked eye???
While not usually classified as a naked eye object, it is close enough
that I expect careful observers under dark skies might be able to see
it. M86 has a very bright core- a quick check of some images I've made
shows it brighter than the core of M31. It is trivially visible with
small binoculars, even under fairly bright skies. Anybody out there ever
tried to see this object without aid?
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Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
David Knisely
in a pair of 10x50 binoculars, but not looking directly up towards it.
M86's total integrated visual magnitude is about 8.9, which is somewhat
beyond the visual limiting magnitude record which a few "eagle-eyed"
observers have managed to achieve on faint stars logged from true
"pristine" higher-altitude dark-sky sites (about 8.1). More
importantly, it is well beyond the usual 6th to 7th magnitude limits
reported by most amateurs from what they might consider to be a "dark
sky". M81 has been seen naked-eye by amateurs from dark sky sites
(visual magnitude 6.9), as has NGC 5128 (visual magnitude 6.8), but
these two probably represent the most distant objects that are visible
to the unaided eye. Clear skies to you.
David W. Knisely Prairie Astronomy Club:
http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/
Chris L Peterson
wrote:
>Yes, M86 is very likely not visible with the naked eye. I have seen it
>in a pair of 10x50 binoculars, but not looking directly up towards it.
>M86's total integrated visual magnitude is about 8.9, which is somewhat
>beyond the visual limiting magnitude record which a few "eagle-eyed"
>observers have managed to achieve on faint stars logged from true
>"pristine" higher-altitude dark-sky sites (about 8.1).
Well, that raises the question of just how valid integrated magnitude
really is for determining visual appearance. What I looked at were the
peak intensities from some images I've made, and the core of M86 seems
to be brighter than the core of M31. Of course, M31 is so huge that its
integrated brightness is high: 3.5 or something like that. While nearly
everybody can easily see a mag 3.5 star, many people struggle to see
M31. How well our eyes can detect something depends both on the peak
brightness and on the area. Certainly, visual observers know that the
published brightness of galaxies isn't a very good indicator of how easy
they are to see. Small bright galaxies with a low integrated brightness
are often easier to see than large diffuse galaxies with a high
integrated brightness.
M86 looks like a fairly bright, fuzzy round spot in my 8x50 binoculars.
It wouldn't surprise me if it could be seen as a star-like object by an
experienced observer under dark skies. Might be fun to give it a try.
In any case, even if it isn't a naked eye object, it's got to be
borderline- enough that the quoted article isn't making an absurd claim.
David Knisely
The article is making an incorrect claim. There are no reports of any
galaxies other than the Magellanic Clouds, M31, M33, M81 and NGC 5128
being seen with the unaided eye. The M81 and NGC 5128 sightings are
quite rare and were considered fairly marginal by those who managed to
see them, with the objects looking like very faint stars. I managed to
see M81 with my unaided eye a number of years ago on a night where the
zenith limiting magnitude was around 7.1, but that was one night in a
hundred where conditions were that favorable (and M81 was high in the
sky). Thus, I consider a naked-eye visual sighting of any galaxy with
a total integrated visual magnitude fainter than 8.0 to be very highly
unlikely.