In de Hagedis, een onopvallend sterenbeeld tussen de Zwaan en Andromeda, kan je momenteel een sterrenstelsel in uitbarsting zien. Het gaat over BL Lac, een AGN (active galactic nucleus) blazar die zijn energie haalt uit een superzwaar zwart gat in het centrum. Dat dit type object in helderheid varieert is dus normaal, maar het was alweer van 2004 geleden dat hij nog zo helder was. Met wat geluk haalt hij magnitude 13 (of meer?). Heb je nog nooit een blazar gezien, grijp dan je kans. Ik heb hem gisterenavond alvast gevonden!

Een zoekkaartje kan je maken met de variable star plotter van de AAVSO: http://www.aavso.org/vsp
Een detailkaart met vergelijkingssterren vind je hier: http://www.aavso.org/vsp/chart/pl/8277AHV

Laat weten hoe helder je BL Lac schat en stuur je waarnemingen door. Dat kan eveneens naar de AAVSO: http://www.aavso.org/webobs/

Hieronder nog de aankondiging van de AAVSO:

AAVSO Special Notice #290

Blazar BL Lac bright
July 24, 2012

The blazar BL Lac, the prototype of this class of variable
objects, has brightened in the optical and radio wavelengths.
ATel #4271 (Sh. A. Ehgamberdiev et al.) on July 23 announced
this brightening. The Atel team reported that "the source
brightness has recently increased from R = 13.66 +/- 0.01 on
July 19.82 to R = 12.60 +/- 0.01 on July 22.97. This episode
is similar to those that occurred in June 2012 (Atel #4155)
and May 2011 (ATel #3371)."

Gary Poyner (Birmingham, England) reported BL Lac in outburst on
2012 July 23.057 UT at visual magnitude 13.2 (cvnet-outburst 4840).

As Mike Simonsen (Imlay City, MI) notes in his 2012 July 23 posting
to the AAVSO Campaigns and Observation Reports forum
(http://www.aavso.org/forums/variable-star-observing/
campaigns-observation-reports,
http://www.aavso.org/bl-lac-outburst), observations in the AAVSO
International Database (AID) indicate that BL Lac has not been
this bright since August 2004, when it reached visual magnitude
12.9 and was bright for about a month. Previous to the 2004
brightening, as shown in the AID, BL Lac had gone through a series
of brightenings 1997-2004, reaching visual magnitude 13.0.

Recent observations reported to the AAVSO include:
2012 Jul 11.9201 UT, 14.6 (K. Wenzel, Grossostheim, Germany);
11.9208, <14.3 (J. Ripero Osorio, Madrid, Spain);
12.2813, 14.5 (M. Simonsen, Imlay City, MI);
15.9028, <14.3 (Ripero Osorio);
17.8993, 14.0 (Ripero Osorio);
18.9785, 14.4 (P. Dubovsky, Kolonica, Slovakia);
20.0158, 13.7 (Ripero Osorio);
21.0162, 13.6 (Ripero Osorio);
21.2129, 13.761 V +/-0.004 (B. Harris, New Smyrna Beach, FL);
21.9549, 13.1 (Wenzel);
22.3754, 13.665 V +/-0.004 (Harris);
23.0570, 13.2 (G. Poyner, Birmingham, England);
23.3932, 13.190 V +/-0.005 (Harris);
23.3968, 13.196 V +/-0.004 (Harris);
23.4005, 13.202 V +/-0.004 (Harris);
23.4071, 13.213 V +/-0.013 (Harris);
23.8924, 13.0 (Wenzel);
23.8931, 13.4 (W. Kriebel, Schierling/Walkenstetten, Germany);
23.9035, 13.5 (Dubovsky);
23.9460, 13.2 (Poyner);

Coordinates: 22 02 43.29 +42 16 39.9  (2000.0)

Charts for BL Lac may be created using the AAVSO Variable Star
Plotter (VSP): http://www.aavso.org/vsp

Please report observations to the AAVSO International Database
as BL LAC.

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


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