[vsnet-alert 13271] Fw: P Cygni Campaign

[Daisaku NOGAMI]

Begin forwarded message:

Date: 28 Apr 2011 13:40 GMT
From: "Ernst Pollmann" <ernst-pollmann at t-online.de>
Subject: P Cygni Campaign


Dear colleagues !


The ASPA-working-community (Germany) has started in November 2008
together with the 
German association for variable stars BAV, an international observing
campaign on 
photometry and spectroscopy at the "Bright Blue Variables" LBV star P
Cygni. 
 
High precision (< 0.05 mag) instrumental V-band photometry is requested
to correlate with 
spectroscopic measurements of the equivalent width of the hydrogen
(H-alpha) spectral line.  
It is suspected that the photometric brightness and H-alpha line
equivalent width might be 
correlated and variable on similar timescales. 
 
The purpose of the campaign is the continuation of an investigation of a
professional 
Bulgarian astronomer named Nevjana Markova from the years 1998-2001.
High precision                                                        (<
0.05 mag) instrumental V-band photometry is requested to correlate with
spectroscopic 
measurements of the equivalent width of the hydrogen (H-alpha) spectral
line.  It is suspected 
that the photometric brightness and H-alpha line equivalent width might
be correlated and 
variable on similar timescales. 
 
This project may continue indefinitely; we ask that the star be added to
the observing queues 
of as many observers as want to participate.  Rapid time-series are not
required; intra-day 
variability does occur, but large variations are expected to occur with
timescales of weeks or 
longer.
 
This project is ideal for photoelectric observers, but may also be done
by CCD observers able 
to observe bright stars.  Please use at least a Johnson V filter; other
filters may be used in 
addition to V, but V is the primary filter for this study.  
 
Observers are also strongly encouraged to transform their data if at all
possible.  PEP data 
processed through the WebObs/PEPObs system are transformed
automatically.  CCD 
observers: please be very clear as to the comparison star used to
perform differential 
photometry, and be careful to avoid saturating the variable.

Many thanks in advance, 
Ernst Pollmann
--------------------------------
Active Spectroscopy in Astronomy
http://www.astrospectroscopy.de
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Daisaku NOGAMI <nogami at kwasan.kyoto-u.ac.jp>