mu1 and mu2 scorpii?
tigger
i was at a friend's condo just now (looking after her cat while she is
away) and they had a pair of 12x50 china binocs handy so i was out on
the balcony looking around for something recognizable, and there was
scorpius in all splendour.
now, i noticed 2 stars close together in the upper part of the tail, a
check with my peterson's later shows they are mu1 and mu2, does this
notation indicate a double? i could split them easily naked eye so i
was just wondering.
also, i rem reading before that there was an ngc object near one of
the brighter stars in scorpius' body so i swept my binocs around and
boom! unmistakable, a little smudge above zeta (1 and 2 again),
averted vision revealed a sprinkle of stars, very thrilling. my first
view of ngc 6231, not a difficult object by any standard i'm sure but
most enjoyable.
oh yes, forgot to mention, transparency was below average, thin layer
of clouds, sky was like a very dark grey rather than black.
happily
tigger
_
Urban Astronomer
http://www.stargazing.net/urban
Michael A. Covington
> check with my peterson's later shows they are mu1 and mu2, does this
> notation indicate a double? i could split them easily naked eye so i
> was just wondering.
It probably indicates that some later atlas-maker wasn't sure which of them
corresponded to Mu Scorpii in Johannes Bayer's original (1604) atlas.
Tracking down who put superscripts to some Bayer's Greek letters is an
amusing (and probably almost useless) historical exercise...
Taking a look in Starry Night Pro, I find that they are listed with rather
different distances, so probably not a real double. But that doesn't prove
much, since I don't know how reliable those distances are. Looking in Sky
Catalogue 2000.0, I find that they are not listed as a double.
So it's probably an optical pair...
tigger
are there any conditions for a pair to be denoted an optical double or
just any pair of stars "close" to each other can be called an optical
double? any min. distance requirement?
thanks in advance
tigger
On Sun, 6 Aug 2000 10:59:09 -0400, "Michael A. Covington" <See
http://www.CovingtonInnovations.com for address> wrote:
>Taking a look in Starry Night Pro, I find that they are listed with rather
>different distances, so probably not a real double. But that doesn't prove
>much, since I don't know how reliable those distances are. Looking in Sky
>Catalogue 2000.0, I find that they are not listed as a double.
>
>So it's probably an optical pair...
>
>
>
>
_
Urban Astronomer
http://www.stargazing.net/urban
Michael A. Covington
> just any pair of stars "close" to each other can be called an optical
> double? any min. distance requirement?
I don't know of any real conditions... mainly, an optical double is a star
that somebody thought was a binary and it turned out not to be, I suppose.
Peter Hodges
>hi michael
>
>are there any conditions for a pair to be denoted an optical double or
>just any pair of stars "close" to each other can be called an optical
>double? any min. distance requirement?
>
>tigger
<snip>
I have an old (circa 1970) Encyclopedic Astronomy Dictionary which has
"Opticle Double" as a listed entry, defining them as two stars whose
position makes them appear related when in fact they are not.
Peterh.