(cba:news) stars for spetember

Joe Patterson jop at astro.columbia.edu
Sun Sep 6 09:51:21 EDT 2009

Dear CBAers,

Those pesky dwarf novae are taking a little rest (apparently V713 Cep 
didn't have real serious intentions), the bright Moon is soon to leave 
us, and it's a good time to ramp up observing a bit.  In particular, 
it's vital that we now get a couple of September weeks on V4743 Sgr, a 
star we tracked extensively in June and July.  By adding September 
coverage, we accumulate a total of ~120 days of seasonal coverage - this 
gives us enough baseline to count cycles uniquely all the way back to 
2003, and thus establish a precise ephemeris for both the orbital and 
the (presumed) rotational clocks.  That's the really high priority for 
southern observers.

BW Scl is, too.  We have about two uninterrupted weeks now, due to Berto 
and Bob Rea.  Around one more should yield a power-spectrum sensitivity 
almost as good as we could ever theoretically obtain.  So let's keep the 
faith a little longer.

Aside from these two, the other southern star I recommend is VZ Scl. 
We've never done a serious campaign on it, and with the star decently 
bright at 15.6, it's time to train some telescopes on it.  I suspect 
this maybe be a long-term target.

Northern observers have been a little quiet lately.  Maybe the beach has 
been too tempting.  But when you get back from the beach, V455 And 
awaits.  That's my number one recommendation - very long runs on this 
well-placed star.  Shorter runs on RX0022+61 = IGR0023+61, RX1803+40, 
and RX1703-05 would also be good.

Finally, an excellent beginner star is V Sge.  Plenty bright, and with 
deep eclipses which show a period change still not understood (and not 
so securely measured).  Also, it's pretty easy for me to evaluate data 
quality for this star.  Same goes for AO Psc and FO Aqr; these don't 
need any new coverage until December, but they're easy to observe and 
will help me evaluate data-quality issues.

Happy observing!


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