From jop at astro.columbia.edu  Wed Jun  3 06:36:18 2009
From: jop at astro.columbia.edu (Joe Patterson)
Date: Wed, 03 Jun 2009 06:36:18 -0400
Subject: (cba:news) CL Sco active
Message-ID: <4A265222.4060408@astro.columbia.edu>

Dear CBAers,

Berto has found an outburst of CL Sco, and this is a good target for 
southern CBA coverage - plus a few northerners, as the dec is not all 
that extreme.  A blue filter might be a plus, though at mag 11.8 the 
object is likely to be pretty blue anyway (implying that unfiltered 
light will give results very similar to blue light).

Bona fide CVs practically always flicker, and most symbiotics don't.
But the latter *sometimes* do when they go into outburst, and not much 
is known about the origin and nature of that flickering.  The present 
outburst is a really good opportunity to explore that... UNLESS a full 
night's coverage shows no variability at all.  As usual, that degree of 
inscrutability should erase the star from our radar screens.

I finished my quick analysis of V1213 Cen, mostly from Berto's great 
data.  (This is the 11th mag ASAS nova.) The star's variability is 
pretty interesting for a classical nova, but no pattern was apparent 
even from 15 nights of observation.  That's enough to knock it off our 
programs.  Until next year, anyway; often a few magnitudes of decline 
suffices to reveal a nova's inner machinery (after the ejected shell 
disperses).

We didn't organize one, but a significant CBA meeting sort of happened 
spontaneously during the SAS meeting at Big Bear.  Among other things, 
we decided to have organized meetings next May at Big Bear, and May 2011 
at Boston (along with AAVSO and AAS).  More on this later.

joe



-------- Original Message --------
Subject: [vsnet-alert 11282]  CL Sco in active state
Date: Tue, 2 Jun 2009 20:06:39 +0200
From: Berto Monard <bmonard at mweb.co.za>
To: Vsnet-Alert at Ooruri.Kusastro.Kyoto-U.Ac.Jp 
<vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>

The symbiotic star CL Sco has recently entered an active state as shown by
the observations below.

2454622.26  13.16 CCD-V  MLF
2454639.25  13.26 CCD-V  MLF
2454645.42  13.23 CCD-V  MLF
2454658.26  13.20 CCD-V  MLF
2454677.29  13.26 CCD-V  MLF
2454681.27  13.30 CCD-V  MLF
2454701.25  13.27 CCD-V  MLF
2454719.20  13.16 CCD-V  MLF
2454725.22  13.23 CCD-V  MLF
2454732.24  13.20 CCD-V  MLF
2454744.21  13.12 CCD-V  MLF
2454770.25  13.20 CCD-V  MLF
2454884.60  13.08 CCD-V  MLF
2454918.50  13.11 CCD-V  MLF
2454926.50  12.99 CCD-V  MLF
2454940.40  12.79 CCD-V  MLF
2454966.40  11.95 CCD-V  MLF
2454971.30  11.88 CCD-V  MLF

Berto Monard
Bronberg Observatory / CBA Pretoria



From jop at astro.columbia.edu  Tue Jun 16 10:02:17 2009
From: jop at astro.columbia.edu (Joe Patterson)
Date: Tue, 16 Jun 2009 10:02:17 -0400
Subject: (cba:news) stars for june
Message-ID: <4A37A5E9.1010205@astro.columbia.edu>

Dear CBAers,

Time for some (northern) spring cleaning.  The raft of March-April AM 
CVn stars have swung too far over to the west, and the dwarf novae are a 
little quiet these days.  Here's a few tantalizing new stars which are 
well placed for observation during June nights.

V4743 Sgr.  Berto has just opened the season on this guy (now about 16.5 
I think), the remnant of N Sgr 2002.  The spate of periods that the star
showed a couple of years ago still lingers - in fact seems to have 
become a little more intricate - and this new season gives us an 
opportunity to study 'em in great detail.  A great, great target for all 
southern observers... and maybe a few intrepid northerners as well.

V442 Oph.  After many years at magnitude 14, this star apparently has 
declined to V=17, and it's vital that we obtain time-series photometry 
in this low state.  The origin of low states in these stars (the SW Sex 
stars) is still not known, and Nature doesn't offer many opportunities 
to find out, since the low states are very rare.  Get thee to a 
telescope!  At a dec of -17 degrees and transiting near local midnight, 
it's decently placed for most observers, and excellently placed for 
southerners.

For flat-out northern objects, I recommend one very bright star 
(RX1643+34, mag 12.7) which still has not quite (almost, though) yielded 
to our superhump search, and which has also shown some evidence of a 
rapid period - or maybe just an oddly stable QPO.  Still some annoying 
mysteries there.  It's also DQ Her season again - ESPECIALLY if you can 
take data with around a 15 second time resolution (which will easily 
resolve its 71 second signal).


joe