And accretion's blue glare...

From: Joe Patterson <*jop_at_astro.columbia.edu*> Date: Tue, 15 Sep 1998 08:25:45 -0400 (EDT) · jop_at_astro.columbia.edu

Dear CBAers,                                       Sept. 15, 1998.

Well it has been an explosive week for CVs!  Two little-known dwarf
novae in Cygnus have just gone into superoutburst: V1028 and V630.
The former was at 13.6 last night, the latter near 14.5.  We earnestly
desire to know their superhump periods!  The visual coverage found
these outbursts quite early, so I think odds are good that we can track
'em for about 2 weeks.  Nicely timed for many of us: transiting near
midnight, far northern, in the dark of the Moon.

And Elena Pavlenko reports that MV Lyr has popped into one of its
peculiar states with high brightness and a huge wave.  Nothing whatever
is known about these states - they don't even have an observational
name, much less any understanding, and aren't known to occur in any
other star.  At 13.5-14, MV Lyr is still a good target.

So all these targets are excellent.  The best strategy, as usual, is
to pick one and obtain time-series photometry of it, revisiting as
often as possible.  With many revisits, your data will be well
calibrated *internally*, and will have a better chance of overlapping
some other observer (which extends the time series and calibrates your
data externally).

It's somewhat dumb to list so many targets in a given sky sector
(northern evening).  The CBA equivalent of dividing the army.
Nevertheless, here goes: is there anyone out there away from USA
longitudes who can obtain even a single long (4 hr) run on V1974 Cyg?
We have an alias problem, which we probably won't be able to solve
definitively without some help from Europe/Asia.  It's around 16th
mag - could be done by a 16-inch on a really good night, but almost
certainly not with the 10-inchers.

V592 Herculis, V Sagittae, and UU Aquarii should be retired for the
season.  The march of time and the crush of competition.

In the midnight and morning skies, V592 Cas and TT Ari are targets of
choice, both very bright and enormously forgiving of clouds, pitiful
apertures, etc.

Now for our amigos del sur.

Sorry for all the northern bias above!  The worst ever.  But at least
no references to those clear, frosty December mornings.  The best
evening stars del sur are AO Psc, FO Aqr, and HL Aqr.  The first can
actually be done with short (2 hr) observations, though longer is
always better.  HL Aqr is a more typical CBA target, needing a long
run because the expected period is around 3.2 hr (with a modulation of
about 0.07 mag).  But it's a very, very interesting one, and unlike
most CVs the star hardly flickers at all, so you can in principle get
down to a very severe detection limit.

By the way, be not spurning of borderline northerners.  Gordon Garradd
became the world's prime watchdog of V592 Herculis this month.  TT
Ari is an obvious and worthy candidate.

Meetings.  As many of you know, the ASP and the AAVSO are having a
joint meeting in Toronto around July 1-5, 1998, with "Professional-
Amateur Collaboration" a major topic.  We will have something of a CBA
meeting at that time.  I also hope and expect to attend a New Zealand
photometry conference in the week before.

We'll get and send reprints of the Sky and Tel article.  Sorry for the
minor inaccuracies and the omission of a table (or even map) showing
the CBA network.  As I learned, the author doesn't have final, or
perhaps anywhere near final, control over what goes into their
articles.

                   joe