(cba:news) the latest trinkets

Joe Patterson jop at astro.columbia.edu
Wed May 14 06:32:52 EDT 1997

Dear CBAers,                                         May 14, 1997.

     I wanted to mention two other targets thrust on us with short
notice.  "Var21 CrB" (sorry for the funny name, it might have a
slightly better one that I dunno) is in superoutburst and the European
CBAers are tracking its superhumps.  Time for some help from other
longitudes!  Unfortunately I don't even have a position (somewhere
around 1553+33) much less a chart for the guy.  But could one of you
that knows (maybe Tonny, Lasse, Rudolf) supply this info to "cba-news"
(the e-mail exploder)?  This sounds like a good target for the next 7-
10 days at least.

     XTE (X-ray Timing Explorer) is doing a long observation of FO Aqr
spread over May 14-27, with maximum coverage during May 16-21.  FO is
an old friend and we definitely planned a long visit this year.  I
wasn't planning such an early start, but the X-ray observation changes
that.  I now think it's critical to nail this star just before morning
twilight.  No one will be able to get a long run, but by stacking short
runs we can get a good pulse timing.  Southerners will be able to do
much better, because of the star's dec (-8) and more especially the
Sun's (somewhere around +18).  We have an official chart on the
Website, and many of you have paper copies too.  If you've never
observed this star, you're in for a treat; its 21 minute pulse is the
Sirens' Song for all CBAers.

     Now for the other guys.  The campaign on AM CVn slowed down a bit
but is still humming along enough to yield the basic scientific
results.  Keep it up.  The campaign on EC1533-1403 could certainly use
more attention; we're only getting about one hit every 15 days - enough
(I think) to follow the slowly drifting period, but vastly insufficient
to tackle the other interesting issues of fine structure in the period.

     Admittedly, we have conflicting targets now.  Small-scopers will
have a good time on Mister Var21 as long as it's bright, and on FO Aqr
if they can reach that position (2217-08) before twilight (unlikely for
Europe).  AM CVn and EC1533 are your basic all-around good targets, but
become somewhat tough in bright moonlight because their oscillations
are weak (0.02-0.04 mag); also EC1533 is completely clobbered for 3
days every month by a direct lunar visit.  You probably should prefer
V795 Her and V603 Aql when the Moon gets really formidable.  People
with larger scopes can do AM CVn every night, and EC1533 nearly every
night.  I generally recommend that you adopt whichever of these stars
you prefer and pound it hard.  (But if you can observe all night, do
'em both!)

     Jonathan worked hard on the newsletter over the weekend, and did a
really good job as usual.  Send him kudos.  You should get your paper
copy in a few days; it's on the Website too.  We have various things
more or less available for the asking, including the new Downes-
Webbink-Shara catalog.

     Actual sunshine peeking over the mountains here in Vermont.  Rare,
worth a mention.  I promise never to think of New York City as a cloudy
place again.


P.S. Australites forsake not V803 Cen! (only not mentioned because of
our population of biased northerners)

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