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            THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS            
                 25 Birch Street, Cambridge, MA 02138 USA
                 Tel. 617-354-0484       Fax 617-354-0665
                          http://www.aavso.org
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                         C C D   V I E W S   #322
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                              July 28, 2004


THIS IS A SPECIAL EDITION OF CCD VIEWS

Table of Contents
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 1. Chandra and VLA Satellite Observations of V4641 Sgr
 2. FUSE Satellite Observations of VW Hyi

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1. CHANDRA AND VLA SATELLITE OBSERVATIONS OF V4641 SGR

 Dr. Michael Rupen, National Radio Astronomy Observatory, has asked the
AAVSO for CCD monitoring of V4641 Sgr during two observing windows
coming up on July 30 and August 1. These observations will be
coincident with Chandra and VLA observations of V4641 Sgr.  The exact
time for the observing windows are below:

        30 July 2004: 1750-2400 UT -- Chandra
        01 Aug. 2004: 0231-0400 UT -- VLA

 Observations every half hour are requested. However, if you detect
variability while observing please switch to time series observations
with high time resolution. Also, if your schedule allows it, we
recommend taking time series observations beginning an hour before each
observing run and lasting until an hour after each run.
 This object can vary on timescales down to a few seconds so be
prepared for anything. This also means that simultaneous observations
from multiple observers can be combined to get a higher time
resolution. So please make sure your computer clock is synced to an
appropriate server (such as tick.usno.navy.mil) and that your FITS
image records the time as the midpoint of the exposure.
 Dr. Rupen requests that a consistent photometric filter be used with
these observations. Please use a V filter with your observations. A new
AAVSO CCD chart with V magnitudes from A. Henden & B. Sumner has been
posted at this URL:

http://www.aavso.org/cgi-bin/searchcharts3.pl?name=v4641%20sgr

 Our latest visual observation of V4641 Sgr is:
 JUL 22.4430 2453208.943   13.1                  Rod Stubbings (SRX)
 Our latest CCD observation of V4641 Sgr is:
 JUL 07.4704 2453193.9704  13.74  +/- 0.03 Unfiltered Lew Cook (COO)

 V4641 is an X-ray bright novalike variable star. Novalikes are CVs in
a perpetual state of outburst. Information on novalikes can be found in
the in our Spring, 2004 Variable Star of the Season article on UX Uma:
   http://www.aavso.org/vstar/vsots/spring04.shtml

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2. FUSE SATELLITE OBSERVATIONS SCHEDULED FOR 0409-71 VW HYDRI 

 (The text below is taken from Alert Notice #309, issued by
Elizabeth O. Waagen on July 27, 2004.) 

 We have been informed by Dr. Knox Long that the Target-of-Opportunity
observations of the SU UMa-type cataclysmic variable VW Hyi with the
FUSE satellite have been scheduled. According to Dr. Long, "FUSE has
scheduled daily observations of VW Hyi beginning late in the week. We
will observe every day for about 6 days and then once every 3-4 days
through the end of August."

 YOUR REGULAR OBSERVATIONS FROM NOW THROUGH AT LEAST THE MIDDLE OF
SEPTEMBER ARE CRUCIAL!

 We recognize that there is a lot of cloudy weather at this time of
year in the southern hemisphere, so each observation you can make is
all the more precious.

 In order to interpret the data that will be obtained with FUSE, it
will be essential to have a dense optical light curve. VW Hyi is
currently undergoing a supermaximum, as seen by the observations below
that have been reported to the AAVSO. Coverage as the star declines to
minimum, through minimum, and through any outbursts that occur during
August is needed.

 Alert Notices 305, 306, and 308 (please see for details) announced and
discussed the request for optical monitoring of VW Hyi by Dr. Long and
his colleagues.

 We would like to ask two things of you:
  - Please continue to observe VW Hyi at least once a night and
    report your observations to AAVSO Headquarters.
  - Please notify Headquarters immediately if you see VW Hyi go
    into outburst.

 AAVSO 'b' and 'd' scale charts may be found at:
http://www.aavso.org/cgi-bin/searchcharts3.pl?name=vw%20hyi or on
request to AAVSO Headquarters.
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 Good observing!

 Aaron Price, AAVSO Technical Assistant (PAH)
 Gary Walker, Chairman of the AAVSO CCD Committee (WGR)

Copyright 2004, American Association of Variable Star Observers
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           THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
                25 Birch Street, Cambridge, MA 02138 USA
                Tel. 617-354-0484       Fax 617-354-0665
                         http://www.aavso.org
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