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 262 (August 25, 1999) 1415-68 NOVA CIRCINI 1999 We have been informed by William Liller, Vina del Mar, Chile, and by the Central Bureau for Astronomical Telegrams (IAU Circular 7242, http://cfa-www.harvard.edu/iau/Headlines.html) of Liller's photographic discovery, using the PROBLICOM method, of a nova in Circinus, on August 23.0110 and Aug. 23.0125 UT, at photographic magnitude 7.7. The photographs were taken on Technical Pan film with an 85-mm camera lens and an orange filter. The position of the nova as obtained from CCD frames taken with 0.20-m Schmidt camera on Aug. 23.9717 UT was: R.A. = 14hr 23m 23.6s Decl. = -69degrees 08' 45.1" (equinox 2000) The magnitude measured with a broadband V filter was 7.79 at that time. Liller further reports that nothing brighter than magnitude 11.0 appears at this location on two photographs taken on July 15.99. A low resolution spectrum obtained with the Schmidt, an objective prism, and a CCD, on Aug. 23.9874 UT shows H-alpha in emission at a level ~0.85 times brighter than the intensity of the surrounding continuum. The spectrum suggests that the nova outburst occurred a day or two earlier. Additional observations of N Cir 99 reported to the AAVSO include: Aug. 24.3021 UT, 8.4, A. Jones, Nelson, New Zealand; 24.4222, 7.6, R. Stubbings, Drouin, Victoria, Australia; 24.4396, 7.5, Stubbings; 24.4465, 7.6, Stubbings; 24.4500, 7.5, Stubbings; 24.4528, 7.6, Stubbings; 24.4583, 7.6, Stubbings; 24.4625, 7.6, Stubbings; 24.4681, 7.5 Stubbings; 24.4701, 7.6, Stubbings; 24.4722, 7.5, Stubbings; 24.4771, 7.6, Stubbings; 24.581, 8.1, A. Pearce, Nedlands, Australia; 24.707, 8.7, L. Monard, Pretoria, South Africa; 24.777, 8.8, Monard; 24.790, 8.5, B. Fraser, Sunninghill, South Africa; 24.844, 8.7, J. Hers, Sedgefield, South Africa; 25.459, 8.1, Pearce; 25.501, 8.0, Pearce; 25.538, 8.1, Pearce; 25.937, 8.1, J. Garcia, Buenos Aires, Argentina. Accompanying is a CCD-V image of N Cir 99 obtained by William Liller on Aug. 23.9717. The field measures 27' by 36'. Also accompanying is a "c" scale AAVSO preliminary chart of N Cir 99 prepared by C. Scovil. Please use this chart to observe 1415-68 N Cir 99, and report your observations to AAVSO Headquarters, making sure to indicate which comparison stars you used to make your magnitude estimate. Congratulations to Bill on his latest discovery! FADING OF 1544+28A R CORONAE BOREALIS We have been informed by our observers that R Coronae Borealis, the prototype of the R CrB stars, is fading. R CrB, which is approximately visual magnitude 6.0 at maximum, is reported to be at approximate magnitude 11.4 as of August 24 UT. Observations of R CrB reported to the AAVSO since July 15th indicate that this star began to fade in late July. The last fading of this star occurred in August 1998 - March 1999, during which R CrB faded to visual magnitude 8.4, brightened to magnitude 7.2, faded once again to magnitude 9.6, and then recovered. Fadings of R CrB are unpredictable both in duration and in the magnitude to which the star may fade. Please monitor R CrB closely and report your observations of this interesting star to AAVSO Headquarters. AAVSO "a", "b", "c", "d", and "e" scale standard charts for R CrB have been posted on our ftp site; see below for details. Those needing paper copies of these charts should contact AAVSO Headquarters. UPDATE ON TWO RECENT NOVAE AND AM HERCULIS 1903+12 V1493 AQUILAE (N AQL 99) V1493 Aql was discovered in mid-July at photographic magnitude 8.8 (see AAVSO Alert Notice 261.) Observations reported to the AAVSO indicate that the nova had faded to approximate visual magnitude 12.8 by early August, and then began to slowly brighten. The nova is reported to be at visual magnitude 12.0 as of August 24 UT. AAVSO "c", "d", and "e" scale preliminary charts for V1493 Aql (N Aql 99) have been posted on our ftp site; see below for details. Those needing paper copies of these charts should contact AAVSO Headquarters. 1040-51 V382 VELORUM (N VEL 99) V382 Vel was at approximate visual magnitude 3.0 at the time of its discovery in May (see AAVSO Alert Notice 259.) AAVSO observations indicate that since its discovery the nova has continued to slowly fade. The nova is reported to be at visual magnitude 7.9 as of August 22 UT. AAVSO "aa" and "b" scale preliminary charts for V382 Vel (N Vel 99) have been posted on our ftp site; see below for details. Those needing paper copies of these charts should contact AAVSO Headquarters. 1813+49 AM HERCULIS AAVSO observations indicate that the magnetic variable AM Her is currently brightening from its recent low state. AM Her began fading in May and reached visual magnitude 15.2 in early July. Observations reported to the AAVSO since July 1st show that AM Her remained at its low state until mid-August when it began to brighten. The variable is reported to be at visual magnitude 13.4 as of August 25 UT. AAVSO "b", "d", and "f" scale preliminary charts for AM Her have been posted on our ftp site; see below for details. Those needing paper copies of these charts should contact AAVSO Headquarters. LIGHT CURVES The light curves (through June 1999) of the objects mentioned in this Alert Notice may be plotted on our web site (www.aavso.org) by clicking on "Light Curves" and using the online light curve generator. We are currently processing the monthly reports of observations made in July. Therefore, the July data can not yet be accessed with the light curve generator. Observations which have been reported on a nightly basis since July 1, 1999 can be viewed via our web page in the AAVSO "Quick Look" File. CHARTS AVAILABLE ON AAVSO WEB AND FTP SITES Electronic copies of the N Cir 99 chart, the CCD(V) image of N Cir 99, and the other charts mentioned in this Alert Notice are available through our web site at the following address: http://www.aavso.org The charts may also be obtained directly from our FTP site: ftp.aavso.org (198.116.78.5), in /alerts/alert262) The answering machine at AAVSO Headquarters is on nights and weekends for your convenience. Please call our charge-free number (888-802-STAR = 888-802-7827) to report your observations. We also encourage observers to send observations by fax to 617-354-0665 or by e-mail through the Internet to observations@aavso.org. If you need to change the email address this Alert Notice is sent to, or if you would like to stop receiving the Alert Notice by email, please visit the following URL: http://www.aavso.org/mailinglists.stm Many thanks for your valuable astronomical contributions and your efforts. Good observing! Janet A. Mattei Rebecca Pellock Kerriann Malatesta Director Technical Assistant Technical Assistant