THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
INTERNET: aavso@aavso.org
Tel. 617-354-0484 Fax 617-354-0665
AAVSO ALERT NOTICE 295 (April 16, 2002)
1753-30B NOVA SAGITTARII 2002
We have been informed by the Central Bureau for Astronomical Telegrams (IAU
Circular 7878) that W. Liller, Vina del Mar, Chile, photographically
discovered an apparent nova in Sagittarius at magnitude 9.2 on two images
taken on April 15.354 UT, using Technical Pan film and an orange filter.
P. Cacella, Brasilia, Brazil, measured the position of the object from a
CCD image obtained with a 0.25-m reflector on April 16.093 UT (V magnitude
10.1) as:
R.A. = 17h 59m 59.63s Decl. = -30o 53' 20.5" (2000)
Observations reported to the AAVSO are as follows: April 11.3999 UT, <11.5
PTG, W. Liller, Vina del Mar, Chile; 15.3539, 9.2 PTG, Liller; 16.1290,
9.5, R. Shida, Ariente, Brazil; 16.4854, 9.8, M. Linnolt, San Francisco,
CA; 16.6060, 9.8, A. Pearce, Nedlands, Australia.
Accompanying is an AAVSO "d" scale chart of N SGR 02 prepared by A. Price,
AAVSO Headquarters, with the sequence prepared by M. Simonsen and M. Morel.
Please use this chart to observe the nova, and report your observations of
1753-30B N SGR 02 to AAVSO Headquarters, making sure to indicate which
comparison stars you used. Please note that a "d" scale reversed chart is
also available from the AAVSO web site or on request.
Congratulations to Bill on his latest discovery!
0006-12 WW CET - REQUEST TO MONITOR FOR RXTE OBSERVATIONS
Astronomer Dr. Darren Baskill of Leicester University, Leicester, UK, will
be observing the dwarf nova WW Ceti with the Rossi X-ray Timing Explorer
(RXTE) from May 10 through August 9, 2002, for a duration of 3,000 seconds
each day. He has requested the assistance of AAVSO observers to monitor WW
Cet simultaneously with his X-ray campaign so that the visual and X-ray
data may be correlated. Dr. Baskill provides the following description of
the project:
The relationship between X-ray and optical observations varies
dramatically between dwarf novae. In U Gem, the X-ray count rate
increases during optical outburst, while observations of SS Cyg and SU
UMa (see AAVSO News Flash #772) show completely the opposite; the X-ray
count rate falls during optical outburst.
This may be due to the inclination of the system - U Gem has an
inclination of 70 degrees, whereas SS Cyg and SU UMa have much lower
inclinations of 37 degrees, and 44 degrees, respectively. The
inclination of WW Cet is 54 degrees, and so it is unknown whether it
will behave like U Gem or SS Cyg.
This new data should help us understand the X-ray variability (and the
optical relationship) of dwarf novae.
Observers are urged to monitor the variable closely, particularly during
intervals when RXTE is observing WW Cet. During such time, observations
should be made every 5 minutes. Observers should start observing WW Cet 15
before and should continue 15 minutes after scheduled RXTE runs. When RXTE
is not actively observing the dwarf nova, observations should be made every
hour. (For the timetable, see that URL below.) Accompanying are AAVSO "b"
and "e" scale charts for the variable; the "d" scale chart can be found on
the AAVSO web site. Please use these charts to observe this variable, and
report your observations of 0006-12 WW Cet to AAVSO Headquarters, making
sure to indicate which comparison stars you used. Please note that
corresponding reversed charts are also available from the AAVSO web site or
on request.
More information about this campaign, including RXTE observing timetables
for WW Cet, can be found at the following address:
http://www.star.le.ac.uk/~dbl/xtewwcet.html
Good coverage from our observers is extremely important to the success of
this observing program. Please observe WW Cet as frequently as possible.
More information about this project will become available as time
progresses. Watch the AAVSO home page (http://www.aavso.org) for updates
and reminders!
CHARTS AVAILABLE ON AAVSO WEB AND FTP SITES
Chart links obsolete, 11/2013: Create charts using VSP at http://www.aavso.org/vsp
Electronic copies of the N Sgr 02 and WW Cet charts mentioned in this Alert
Notice are available through our web site at the following address:
http://www.aavso.org/charts/SGR/N_SGR_02
http://www.aavso.org/charts/CET/WW_CET
The charts may also be obtained directly from our FTP site:
ftp://ftp.aavso.org/charts/standard/SGR/N_SGR_02
ftp://ftp.aavso.org/charts/standard/CET/WW_CET
We encourage observers to submit observations via our web site (online data
submission tool WebObs), or by email in AAVSO format to
observations@aavso.org. If you do not have AAVSO Observer Initials, please
contact Headquarters so we may assign them to you. The answering machine
at AAVSO Headquarters is on nights and weekends; use our charge-free number
(888-802-STAR = 888-802-7827) to report your observations, or report them
via fax (617-354-0665).
Many thanks for your valuable astronomical contributions and your efforts.
Good observing!
Janet A. Mattei
Director
Kerriann H. Malatesta
Technical Assistant
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