TITLE: GCN CIRCULAR NUMBER: 21634 SUBJECT: LIGO/Virgo G298048: TOROS Spectra observation with CASLEO DATE: 17/08/21 16:05:22 GMT FROM: Martin Bernoiz at TOROS Mario Diaz(UTRGV/CGWA), Diego Garcia Lambas(IATE), Lucas Macri(TAMU), Jose Luis Nilo Castellon(Univ La Serena) We report a spectrum observation of SSS17a in CASLEO Observatory, Argentina. Telescope: Jorge Sahade Reflector Ritchey Chretien Primary mirror diameter: 2153 m Geographic coordinates: Lon = W 69 18 23.16 Lat = -31 47 14.46 Reosc Spectrograph Diffraction grating of 300 lin/mm (blaze at 500 nm) Simple dispersion configuration Slit width of 350 microns = 1 arcsec Spectral Resolution: 13.5 Angstrom Slit Orientation: E-W Observations performed on 08/19/2017 (the night of 18) starting at approximately 00:15 UTC finishing at approximately 01:30 UTC Performed 3 integrations of 1200 seconds Atmospheric conditions: clear sky; seeing approx. >2 arcsec Martin Beroiz on behalf of TOROS Collaboration.