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CCD Views #317


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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   #317
                            --------------------------
                               December 11, 2003

              
 THIS IS A SPECIAL EDITION OF CCD VIEWS.

 Table of Contents
 -----------------
 1. Urgent Plea For CCD Observations of U Gem! 
 2. UZ Boo Superoutburst 

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1. URGENT PLEA FOR CCD OBSERVATIONS OF U GEM

 We have had a CCD observation that indicates U Gem _may_ be going into
outburst. Right now the moon is extremely close to U Gem, which makes it
almost impossible for visual observers to make observations. With a CCD,
however, the proximity of the moon is not such a problem. PLEASE try to
observe U Gem TONIGHT and let us know right away what you find. Submit your
observation to the quick look file, and if you are sure it is going into
outburst - it is brighter than 13.5 - also please call me at home at
781-316-2304 (it doesn't matter how late it is).

 It is essential for the astronomer who has target-of-opportunity
observation time to be alerted as early in the outburst as possible so he
may schedule NASA's Rossi X-Ray Timing Explorer (RXTE) satellite. With 
most of the visual observers out of the loop at this particular moment, we 
are counting on you and your CCD!

 Many thanks for your help!

Clear skies,

Elizabeth Waagen
Interim Director

Latest observations of U Gem from the AAVSO Quick Look file:

  DEC 08.8132  14.0   VJA   Lunar Interference
  DEC 09.3750  14.1   RR    CCDV
  DEC 11.3750  13.7   RR    CCDV
  DEC 11.4306 <12.5   LMK   Lunar Interference, Clouds, Light Pollution

  VJA  VIRTANEN, JANI   YLIVIESKA, FINLAND
   RR  RON ROYER        SPRINGVILLE, CA
  LMK  MICHAEL LINNOLT  HONOLULU, HI
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2. UZ BOO SUPEROUTBURST

 UZ Boo appears to be in superoutburst for the first time in nine years. 
The last outburst of UZ Boo was in 1994 and before that 1978. In 1994 it
peaked around 11.5 before fading slowly over a few weeks according to
AAVSO data.

 There is *very* little positive data on this star, especially prior to 
outburst.Please turn your guns on this sucker and get as much good quality 
data as possible. V filter is preferred, followed by B.

 Continuous time series observations of UZ Boo are needed! Tonny
Vanmunster and Arto Oksanen have contributed wonderful data but they need
your help. Tonny's preliminary analysis of his data reveals an early
period of around 109 minutes. However, Howell et al. published an orbital
period of 77 +/- 8 minutes in 1988. Tonny's was unfiltered while Howell's
data was in V. Previously in 1987, Szkody detected a 3 hour period(!) in B
but says the period may be variable due to appearances of the hot spot
every now and then. But the V data during the same time span doesn't have
the 3 hour period. It is possible that this star's light curve is heavily
filter dependant. This could be fun. :)

 Please observe as long as possible. Stick with V first. But if you have a
B-filter available e-mail me and we'll try to coordinate an observing run
in B while someone else covers the V.

 Superhump appearance should be evolving now so coverage over the next 7
days is crutial.

 It is also possible that UZ Boo may go through echo outbursts similar to
another UGWZ star, EG Cnc. Although that was not detected visually in the
1994 outburst, these don't manifest themselves until after the
superoutburst is over and UZ Boo was probably too faint for the visual
observers to detect them at that time.

 So there is lots of great stuff going on here. Here is a temporary page
of UZ Boo light curves:
            http://www.aavso.org/tmp/uzboo/
 Charts: 
http://www.aavso.org/cgi-bin/searchcharts3.pl?name=uz%20boo

Aaron

references:
Howell et al. bibcode: 1988PASP..100..224H
Szkody et al. bibcode: 1987ApJS...63..685S
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     CCD Views is published when circumstances warrant via e-mail. 
An archive is available at http://www.aavso.org/ccdviews/ .  
Please send comments and suggestions to aaronp@aavso.org.

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     The AAVSO has many free online publications including "Eyepiece
Views", a similar newsletter intended for visual observers. To learn
more and subscribe visit: http://www.aavso.org/mailinglists.stm

 Good observing!

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


Copyright 2003, American Association of Variable Star Observers
---------------------------------------------------------------------------
           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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