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Alert Notice 149: Outburst of 1825-29 V1017 Sagittarii AND 1834-23 V348 Sagittarii AND Fading of 1808-29 VZ Sagittarii AND Acknowledgements and reminders

THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
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Tel. 617-354-0484 FAX 617-354-0665
    

AAVSO ALERT NOTICE 149 (October 1, 1991)

OUTBURST OF 1825-29 V1017 SAGlTTARII

John Bortle has alerted us to the brightening of VI017 Sgr, classified as a
symbiotic star in the fourth edition of the General Catalogue of Variable
Stars
, as indicated by the following observations made by him and confirming
observations made by David York and Charles Scovil:

Sep 13.1 UT, <13.0 Bortle
Sep 28.033, 12.6 Bortle  
Sep 29.010, 12.6 Bortle
Sep 29.104, 126 York 
Sep 30.015, 12.6 Bortle
Sep 30.104, 12.5 York
Oct 1.02, 12.5 Scovil

This star was reported on July 7.7 at magnitude 13.5 by TIDl Cooper and on
July 19.7 at 13.5 by Danie Overbeek. Danie reports that VI017 Sgr was oscillating
between 13.3 and 13.5 between Aug 2 and Sep 17, as 27 observations made by him
indicate. On Sep 29.74 Danie independently observed VI017 Sgr at 13.1 and on
Sep 30.74 at 12.8.

VI017 Sgr has had three recorded outbursts: in 1973, when the star reached about
10th magnitude; in 1919, when it was reported at magnitude 7.2 on Harvard photographic
plates; and 1901, when it reached about magnitude 10.8. The rise to maximum is slow.
It is interesting to note that the interval between the present outburst and the
1973 one is 18 years, between 1973 and 1919, 54 years (3 times 18), and between 1919
and 1901 18 years. The third edition of the GCVS classified VI017 Sgr as a recurrent
nova.

Accompanying is an "e" scale chart for VI017 Sgr. Observers are urged to monitor it
and to inform us of its behavior.

1834-23 V348 SAGlTTARII

This interesting variable, classified as Unique and showing R Coronae Borealis-type
behavior, is reported by Danie Overbeek to be brightening. On Sep 29.74 he
observed it at magnitude 13.7, and on Sep 30.74 at 13.7. This star has been at
minimum ( < 15.0) since February 1991. Usually the maximum is about magnitude 11.8.

Please use the accompanying "f" scale chart to observe V348 Sgr and report your
observations to AA VSO Headquarters.

FADING OF 1808-29 VZ SAGITTARII

This R Coronae Borealis star has started to fade, as indicated by the following observations:

Sep 1.86 UT 10.4 A. Pereira  Sep 29.0 12.2 Bortle Sep 29.712.0 Overbeek 
Sep 30.712.0 Overbeek   Sep 26.83 < 11.7 ( - 1201) Pereira

Please observe this star with the accompanying "e" scale chart, and report your
observations to AAVSO Headquarters. The Headquarters answering machine is on
evenings and weekends (617-354-0484).

ACKNOWLEDGEMENTS AND REMINDERS

We extend the sincere thanks of the astronomers monitoring dwarf novae during
the recent IUE observing run (see AAVSO Alert Notice 148). To those observers
who kept a close eye on dwarf novae and called Headquarters, your information
was very much appreciated by the astronomers, and of course, by us.

Reminder: Please keep an eye on the 10 high-galactic-latitude cataclysmic
variables for which astronomers observing with the IUE have a standing request
to be alerted when any of them go into outburst (see AAVSO Alert Notice 145).

As always, many thanks for your efforts and very valuable contributions.
Good observing!

Janet A. Mattei
Director

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