Time resolved (40-sec resolution, ~6-hours per night), R-band photometry of the outbursting black hole candidate XTE J1118+480 (ATEL #383) was obtained with the...

We report the discovery of a new outburst of the black hole X-ray transient XTE J1118+480 (IAUC #7418, ATEL#64, #67). Observations carried out with the 0.8m...

GX 339-4 is currently brightening at X-ray, UV, optical and radio frequencies (ATel #1945, #1954, #1960). Our monitoring campaign with the Faulkes Telescope...

In ATel #1599; Krimm et al. report a gradual brightening and softening of SWIFT J1753.5-0127's X-ray emission, using the SWIFT satellite on June 30, 2008. We...

Observations of the black hole binary XTE J1859+226 revealed an unexpected optical re-brightening. Images were taken with the Nordic Optical Telescope (NOT)...

We observed the black hole candidate XTE J1752-223 (ATel #2258) with the William Herschel Telescope (WHT) and the ACAM imager/spectrograph at the Observatorio...

We performed optical spectroscopy of the candidates inside the gravitational wave errorboxes (S190408an, S190425z, S190426c, S190510g, S190728q, S190814bv). The...

Spectra of the optical counterpart to the gamma ray source SWIFT J1753.5-0127 (ATEL #546,#547,#549,#550) were acquired on 2005 July 3th 03:52-09:48 UT with the...

Optical spectra (range 600-690 nm; resolution 6000) were obtained during the current outburst of this black hole binary on July 4.65-4.75 UT with the Siding...