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AAVSO International Database

Special Notice #205: Rapid fading in the luminous blue variable S Doradus

April 15, 2010: Noel D. Richardson and Douglas R. Gies (Georgia State University) announced on 2010 April 14 (Astronomer's Telegram #2560) that S Doradus is currently fading in optical brightness, while its hydrogen Balmer line (H-alpha) brightness is increasing. The V-band magnitude of S Dor (as measured by ASAS-3; Pojmanski, G., 2002, AcA 52, 397) has been declining for more than a thousand days. The star began a more rapid decline earlier this year, and is now fainter than V=9.5.
Tags
AAVSO Special Notice
S Dor
Luminous Blue Variable
AAVSO International Database

Special Notice #206: Request for photometry of the dwarf nova SS Cygni

April 21, 2010: Further to AAVSO Special Notice #204 (2010 April 15), we are requesting additional observations of the bright dwarf nova SS Cygni currently in outburst. SS Cyg is currently beginning a dwarf nova outburst, and observations of this star made with the EVLA have detected the source at radio wavelengths. Observations of SS Cyg have been scheduled with the VLBA on 2010 April 22 and April 23.
Tags
AAVSO Special Notice
SS Cyg
dwarf nova
radio observations
EVLA
VLBA
AAVSO International Database

Special Notice #204: Request for monitoring of SS Cygni in support of EVLA/VLBA radio observations

April 15, 2010: Dr. James Miller-Jones (NRAO, Charlottesville) requests the assistance of AAVSO observers to provide rapid notification of the next outburst of the dwarf nova SS Cygni. A confirmed detection of an outburst will be used to trigger-radio wavelength observations of SS Cygni using the NRAO's EVLA and VLBA radio telescopes. Radio observations will be used to study jet formation in dwarf novae, and rapid notification of the onset of outburst is needed. This project follows in the footsteps of a previous campaign by Dr.
Tags
AAVSO Special Notice
SS Cyg
radio observations
EVLA
VLBA
AAVSO International Database

Alert Notice 506: Alpha Com eclipse observing campaign

January 16, 2015:  THIS CAMPAIGN HAS BEEN CANCELLED. PLEASE SEE AAVSO SPECIAL NOTICE #395 FOR DETAILS.

 

December 5, 2014: Drs. Matthew W. Muterspaugh and Gregory W. Henry (Tennessee State University) have requested AAVSO observers' assistance in monitoring the possible Algol-like binary star alpha Com before, during, and after the eclipse they have predicted for mid-to-late January 2015.

Tags
observing campaign
front page news
eclipsing binary
eclipse
alpha Com
alf Com
AAVSO International Database

Alert Notice 504: Epsilon Aur monitoring during predicted pulsation phase

Note: A thread for this campaign has been created in the AAVSO Campaigns and Observation Reports discussion forum: https://www.aavso.org/eps-aur-monitoring

CONTINUED AT LEAST THROUGH 2021  -  Elizabeth O. Waagen, 17 April 2020

September 17, 2014: Dr. Robert Stencel (University of Denver Astronomy Program) has requested that AAVSO observers monitor epsilon Aurigae from now through the end of the observing season.

Tags
eclipsing binary
citizen sky
AAVSO International Database
front page news
AAVSO Alert Notice
eps Aur

Alert Notice 503: Request for regular monitoring of the symbiotic variable RT Cru

Notes:  Please continue to monitor RT Cru as it continues to decline slowly from its outburst that began in 2021 and after it returns to minimum.  -  Elizabeth O. Waagen, April 4, 2023

This campaign has been extended indefinitely. Dr. Karovska requests monitoring of RT Cru until further notice.  -  Elizabeth O. Waagen, 17 April 2020

Tags
AAVSO Alert Notice
RT Cru
front page news
symbiotic variable
Type Ia supernova
Chandra
AAVSO International Database
X-ray source

Special Notice #386: ASASSN-14cl New large-amplitude cataclysmic variable

June 20, 2014: Kris Z. Stanek (The Ohio State University) et al. reported the discovery during the ongoing All-Sky Automated Survey for SuperNovae (ASAS-SN) of a bright transient (10.66V) on 2014 June 14.52 UT. Data were obtained using the quadruple 14-cm "Brutus" telescope in Haleakala, HI (hosted by Las Cumbres Observatory Global Telescope Network).(ATel #6233, http://www.astronomerstelegram.org/?read=6233)

Tags
ASASSN-14cl
AAVSO Special Notice
front page news
AAVSO International Database
WZ Sge-type

Special Notice #385: SBS 1108+574 HST/COS observations crucial NOW

May 13, 2014: The HST/COS observations of the cataclysmic variable SBS 1108+574 described in AAVSO Alert Notice 501 and Special Notice #384 are scheduled for 2014 May 16 06:19:04 - 15:16:56 UT.

Your observations TONIGHT AND PARTICULARLY TOMORROW NIGHT ARE CRUCIAL!

Tags
AAVSO International Database
AAVSO Special Notice
cataclysmic variable
COS
CSS 120422:111127 571239
front page news
HST
SBS 1108+574
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