(cba:news) stars of april

Joe Patterson jop at astro.columbia.edu
Mon Apr 14 00:43:00 EDT 1997

Dear CBAers,                                         April 14 I think

Whew, finally near the end of this marathon observing run!  Since my
last note, the weather cleared and we've worked almost nonstop.  Mainly
on V803 Cen.  It has also been clear in Chile (Jonathan) and moderately
clear in New Zealand (Stan), so we've done well with global coverage
despite all that damn water down south.  The next message gives a
portion of the light curve, showing the outbursts at P=~23.5 hr - truly
a period rewarding good longitude distribution!  It's an intensity
scale corresponding to counts per 5 seconds above the atmosphere.  7600
corresponds to B=15.00, so the star ranges from 14.7 to 13.2.  The
Chile data is absent, which is why you don't see any maxima (they all
occur over South America, while minima occur over Africa).

Bravo for that New Zealand data, by the way; 10" telescope, and
"off-the-grid"!  (Is that right, Stan?  Keep those gerbils running.)

Of course the star also flashed its usual 1611 s superhumps, and Dave
Buckley obtained long spectral coverage over 7 nights with the 74-inch,
so there is opportunity to learn plenty from this remarkable episode of
rapid outbursts.

The SAAO coverage ends April 15, Chile 3 days later.  How are we going
to extend our coverage later?  Anyone have any bright ideas?  I sounded
the VSNET bugle, but I don't think it has many southern listeners.

Imagine that... dwarf nova eruptions every 24 hr... What will the AAVSO
do?  Announcing the eruptions is now like announcing sunrise.  It'd be
more interesting to announce non-eruptions.

                *          *          *          *

The northern object of choice right now is definitely DV UMa, alas far
outside my ken at present.  The one night of data I saw (spliced from
Tonny, Dave E, Dave W) showed a mighty stimulating power spectrum, and
we urgently need data to confirm this and to track the photometric
waves over the next few weeks.  Dense, dense coverage is the way to go
when the star is multi-periodic, which is probably true here.  Tonny is
the chief entrepeneur on this star, by the way.

The other northern/equatorial targets which we are covering over the
observing season are AM CVn, EC1533-1403, and LX Ser.  Pick your
favorite one or two, and hammer away.  (By the way, we have a Kitt Peak
run coming up Apr 21-28, and we want to do LX Ser as the prime target
during that period.)

                *          *          *          *

As many of you know, there is a one-day special session on amateur-
professional collaboration at the June AAS meeting in North Carolina.
I think several CBA members are invited speakers (Dave E, Tonny, Cap'n
Bob), and we hope to use this occasion to troll for new members and
discuss new plans.  How big do we want to be?  Do we want to branch out
to other classes of stars, or all-sky surveys?  How do we want to use
resources (mainly $$) - better cameras, bigger telescopes, better
telescopes?  Do we want to standardize any part of our operation?  (We
haven't yet, other than the choice of target stars.)  Do we want to
reach out to schools and colleges in some manner?  How can I support
you better?  Let me know if you plan to be there; we certainly want to
have one meeting for these discussions, plus other less formal ones of

One more night of watching this looping star in Centaurus, then back to
Cape Town ("Olympic City", as they say here, jumping the gun a bit) for
a week, then back home (Vermont) April 23.


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