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copyright [c] Maurice Gavin - WPO -2001
BL Lac [=QSO 2200+420 at RA 22h 02m 43.3s Dec +42o 16' 40" - E2000] in Lacerta is the architypal AGN* probably containing a massive blackhole. AGN are typically remote N-type galaxies of variable core brightness on a time scale of hours or days and [unlike typical quasars with strong emission lines] exhibit featureless spectra.
my homepage main quasar page quasar images quasar spectra starfields
2001
July 10: Reported recently by VSNET
as "very bright" - BL Lac targeted to see if there was any change at outburst
to the typically bland and featureless spectrum. There wasn't !
However BL Lac's spectrum [bottom right] is noticeably bluer [nearer the zero order image to right] than adjacent mag 12.8 field star GSC 3206-1047 [Megastar data].
This is a fascinating object and amongst the best spectral field images yet obtained at WPO via the Rainbow grating [dispersion 44A/pixel] in non-objective or field spectrograph mode and Starlight Xpress MX9 CCD camera at full resolution.
Note - the transmission grating imposes
an orange colour to the real [zero order] images and they approximate R
mags.
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copyright [c] Maurice Gavin - WPO -2001