[AZ-Observing] Re: [Fwd: Re: Re: Rapid motion binary stars]

Thanks Brian, I've been trying to figure out where to find data on
"fast" double stars for awhile now.  I'll pull that data down and sort
through it.  Since I use a 20" scope I had figured the fainter doubles
would be accessible, at least when at their widest separation.

I appreciate your help.

Steve


>-----Original Message-----
>From: az-observing-bounce@xxxxxxxxxxxxx [mailto:az-observing-
>bounce@xxxxxxxxxxxxx] On Behalf Of Brian Skiff
>Sent: Thursday, March 23, 2006 7:21 PM
>To: az-observing@xxxxxxxxxxxxx
>Subject: [AZ-Observing] Re: [Fwd: Re: Re: Rapid motion binary stars]
>
>>>  REU 1   12:33.5 +0901, 12.6/12.6, 15.9 year period, max 1.2", min
0.2"
>
>     The first thing I do when I ponder an object like this is to
>find out where it actually is:
>
>12 33 17.41 +09 01 15.7  (J2000)
>
>That position is for the year 2000, and it is moving 1".7 per year
>to the west-northwest.
>     The magnitudes:  it happens to be a Landolt standard, a star that
>people use to calibrate photometry.  Landolt gives mean V mag of 12.(5
>(rounding off), so if the components are exactly equal, they are
>mag 13.2 and 13.2, actually visually a couple tenths fainter,
>because the pair are so red (B-V =3D 1.85 --- as red as Betelguese).
>     The faint magnitudes and very close separation (mostly under 0".5)
>indicates the pair will be visible only in maybe 24-inch and larger
>scopes with great optics and perfect seeing.  I'd stick to naked-eye
>stars for such objects.
>
>
>>>  LDS 838 01:38.8 -1758, 12.45/12.95, 26.5 year period, max 2.3", min
>0.3"
>
>     Another very well-known nearby binary, in this case moving twice
>as fast as the first pair, about 3".5 per year proper motion.  The
position
>as of 6 years ago was:
>
>1 39 01.52 -17 57 01.7  (J2000)
>
>    Similar comments about the visibility as above apply to this pair.
>
>
>     A better, more general approach might be to grab the entire
>orbit file from USNO, linked from here:
>
>http://ad.usno.navy.mil/wds/orb6.html
>
>
>I would delete everything that has components fainter than mag 7 or so.
>Then delete everything that has orbit grade of 4 or 5 (all the lousy
>orbits).  Then I'd delete everything that has a semimajor axis
>less than an arcsecond.  Just as a guess, that'll leave at most 50
>pairs (whole-sky) that are bright enough to see when close and have
>some fairly significant motion.  Might be only a dozen in the north.
>
>
>\Brian
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