Alert Notice 178: 1425-50 Nova Lupi 1993 AND Revised finder chart for 1806-29 Nova Sagittarii 1993 AND Successful completion of ORFEUS Mission AND Outburst of 0409-71 VW Hydri

Spetember 23, 1993

1425-50 NOVA LUPI 1993

We have been informed by our member William Liller, Vina del Mar, Chile, of his photographic discovery, using PROBLICOM, of a nova in Lupus at magnitude 8.0 (average of two photographs, TechPan film plus orange filter) on September 19.02 UT. The 1950 position, precessed from the equinox 2000 measurements provided by R.H. McNaught and G. J. Garradd, Anglo-Australian Observatory, is

RA 14h 28m 26.04s Decl. -500 57' 18.2"

A search by Liller of plates taken between January 1991 and May 4, 1993, revealed no star brighter than 11.5 at this position. McNaught and Garradd report that a visual check with ESO B and R and SERC J surveys show no candidate for this object to magnitude 17 and no star in the immediate vicinity displaying an obvious color (IAU Circular 5868). Liller provides the following CCD(V) observations: Sep. 19.987 UT, 7.97; Sep. 20.994, 8.47. D. Overbeek, Edenvale, Africa, reports N Lup 93 at visual magnitude 8.8 on Sep. 23.72 UT. Liller reports that a low-resolution spectrogram taken with an objective prism shows a nova spectrum similar to N Sgr 93; H-alpha and nebular lines features are least twice as intense as the local continuum (IAU Circular 5868).

Please use the accompanying 'b' scale AAVSO chart prepared by C. Scovil in making observations of this new nova, and report your observations to AAVSO Headquarters. The answering machine is on nights and weekends for your convenience.

Our very sincere congratulations to Bill Liller for his second nova discovery within two days!

REVlSED FINDER CHART FOR 1806-29 NOVA SAGITTARII 1993

Accompanying is the revised 'b' chart for Nova Sagittarii 1993 (with the main header 1808­29 VZ Sagittarii). The first version of this chart was distributed with AAVSO Alert Notice 177. The position of the 9.1 star to the west of the nova has been revised, and comparison stars have been added with photovisual magnitudes of 9.5 (for the previously-indicated 9.1) and 10.0, thanks to measurements of a Stamford Observatory plate by C. Scovil. Please check your observations of Nova Sgr 93, and if they are affected by these changes, make any necessary revisions and re-submit them to Headquarters. We apologize for the error on the previous chart.

William Liller provides the following CCD(V) magnitudes for N Sgr 93: Sep. 17.058 UT, 8.51; Sep. 18.015, Sep. 19.041,8.27; Sep. 20.017, 8.75; Sep. 20.988, 8.87. R. Royer, Lakewood, CA, reports N Sgr 93 at visual magnitude 9.1 on Sep. 23.12 UT. D. Overbeek, Edenvale, South Africa, also reports it at visual magnitude 9.1 on Sep. 23.72 UT.

SUCCESSFUL COMPLETION OF ORFEUS MISSION

We have been informed by Dr. Robert Stachnik, NASA's ORFEUS Program Scientist, that after its five-day mission the ORFEUS spacecraft was returned to space shuttle Discovery's cargo bay Sunday, September 19. He reports that: "The overall observing efficiency was very high...in addition to the expected white dwarfs, chromospheric sources, etc., data were also obtained on cataclysmic variables in both temporary and permanent outburst states...an observation of Nova Sagittarii 1993, discovered on Wednesday, showed no significant FUV flux."

Later Dr. Stachnik sent the following electronic message to AAVSO: "This is to express the thanks of the ORFEUS-SPAS team and the NASA Physics Division for the assistance of the AAVSO in connection with the recent flight of ORFEUS. The mission was highly successful and some of the most exciting observations were the result of AAVSO efforts. While AAVSO is justly proud of its designation as an amateur organization, that designation is appropriate in only the most restrictive sense. The professionalism of your membership and of the Cambridge office is legendary. Thanks so much for your help."

We very much appreciate and thank our observers for the dedicated monitoring of ORFEUS observing targets and other cataclysmic variables, and for the timely phone calls that were vital to the success of the ORFEUS mission.

OUTBURST OF 0409-71 VW HYDRI

VW Hyi is scheduled to be observed at minimum with the Hubble Space Telescope on September 25. Please phone in your observations of VW Hyi to AAVSO Headquarters so we may provide optical data during HST observations.

 

Many thanks for your valuable observations and dedicated efforts.

Good observing!

Director

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