For Vega, which is a telluric standard A0V star, the IGRINS Exposure Time Calculator (Version 2.11) gives the estimates shown in the figure below.

The figure shows S/N estimates for 30 & 300 second exposure times with a quad (e.g. ABBA) exposure set.

Park et al. (2014; SPIE Proceedings) find that the observed S/N is ~83% of the predicted value.

Based of IGRINS ETC v2.11 and the deviation from predictions of 83% from Park et al. (2014; SPIE Proceedings), a rough value for the S/N for an A0V star can be estimated using the following equation:

S/N ~ 273sqrt(Nt)10^(-0.2K_mag)

where N = # of exposures, t = exposure time in seconds, Kmag = K-band magnitude.

As a rough guide, the peak counts in the continuum of a single exposure can be examined to guide the final SNR.

Peak counts in single frame continuum:	SNR (per res.) for one ABBA	for 2 ABBA quads
50	55	80
100	80	115
150	100	140
200	115	160
250	130	180
300	140	200
400	160	230
500	180	255
600	200	280
800	235	320
1000	250	360

Browser not supported