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Special Notice #424: Observations of V1656 Sco (ASASSN-16kd) needed during dust formation

October 26, 2016: Further to AAVSO Alert Notice 550, observations of the nova V1656 Sco (ASASSN-16kd = Nova Sco 2016 No. 2 = PNV J17225112-3158349) are requested beginning at once.

Dr. Fred Walter (Stony Brook University (SUNY)) reports that this nova, discovered in September 2016, appears to have entered the dust-making phase, according to K- and H-band data obtained with the Andicam imager on the SMARTS 1.3-m telescope at CTIO (ATel #9673).

Dr. Walter reports that "On MJD 57686.50 [2016 October 25.0 UT] the BVRIJHK magnitudes were 17.2, 16.0, 13.6, 13.0, 10.6, 9.5, and 7.9, respectively. There is no evidence for a dust dip at optical wavelengths. Since 3 October the BVRIJ brightnesses have faded monotonically by 0.05 ± 0.01 mag/day."

Multicolor photometry (BVRIJHK) is requested at least until V1656 Sco is lost behind the Sun. A cadence of a few to several times per night is suggested, with a S/N sufficient for good resolution. Visual observations are also welcome, although the V faintness of the nova may make these unfeasible.

Coordinates (2000.0):  R.A. 17 22 51.46  Dec. -31 58 37.1

Charts: Charts with a comparison star sequence for V1656 Sco may be created using the AAVSO Variable Star Plotter (VSP).

Please submit observations to the AAVSO International Database using the name V1656 SCO.

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


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