(cba:news) YZ Cnc and the campaign

Joe Patterson jop at astro.columbia.edu
Wed Jan 25 11:03:20 EST 2017


Hi CBAers,

They decided *not* to trigger the X-ray observation on the YZ Cnc 
outburst a few days ago.  All the pieces weren't quite in place.  Good 
chance on the next one though, possibly 4-8 days away (very roughly). 
So keep up the long time series.  Two other things that would be helpful:

(1) Post to cba-chat as well as cba-data.  That way, everybody gets it, 
and can study your data in conjunction with their own to form a judgment 
as to when the outburst is "beginning".

(2) If you're able to cover the star quite a bit, compare your data with 
that already in the AAVSO archive to make a guess about this.  Let us 
know your guess (through cba-chat); it's of much more value than those 
of us who, like me, just read emails!

(3) It's probably best if you submit actual magnitudes rather than just 
delta-magnitudes.  About half of CBAers customarily use 
delta-magnitudes, since they're, strictly speaking, more accurate.  But 
your magnitudes will be more *useful* if you add the magnitude of the 
comp star, or some known comp star.  And if you are very familiar with 
the field and have some particular comp star you favor, let us all know. 
  I think Enrique uses the AAVSO 137 star (V = 13.688).

That's true in general, also - that your estimate of actual magnitude, 
not delta-mag, is more useful.  In the time-series analysis, I usually 
subtract the mean anyway, so it doesn't corrupt anything - and it shows 
at a glance, though admittedly roughly, whether the star is in a "high" 
or "low" state.  V_comp + delta-mag is usually the best way to go.

joe p
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