August 9, 2016
V1687 Cyg spectroscopy and sequence
Further to AAVSO Alert Notice 546, spectroscopy of V1687 Cyg (WR 140, HD 193793) is encouraged. A group of amateur spectroscopists in Germany will be taking spectra in accordance with the parameters given by the astronomers, namely a resolving power >~5000, S/N~100, ideally concentrating on the wavelength region 5500-6000A. A background document sent to these spectroscopists may be found here. Dr. Richardson and colleagues would welcome your participation - if you are interested in contributing spectroscopy as outlined above and in the document, please contact Thomas Eversberg <thomas.everbserg at dlr.de>.
Also, the sequence for V1687 Cyg is in place, but because the star is so bright, small-scale charts will not show any comparison stars. Choose an 'A', 'AB', or 'B' scale chart (900, 450, or 180 arcmin field of view, respectively) for useful comparison stars. A 'C' scale chart (120 arcmin) will show sufficient (although faint) stars for CCD/PEP/DSLR work.
Coordinates (2000.0): R.A. 20 20 27.98 Dec. +43 51 16.3
Charts: Charts with a comparison star sequence for V1687 Cyg may be created using the AAVSO Variable Star Plotter (VSP).
Please submit observations to the AAVSO International Database using the name V1687 CYG.
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This Special Notice was compiled by Elizabeth O. Waagen.
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