SIMBAD references

It is estimated that PSN K0210-1 was first detected no more than 60 days past maximum light and so was never brighter than K' = 13.4, assuming an average fading of 0.02 mag/day from Mattila and Meikle (2001, MNRAS 342, 325, Table 5); it is anticipated that K0210-1 experienced about 1 mag of extinction in K'. If the limiting mag is 21 near the nucleus in the optical for PSN K0210-1, then these observations suggest about 6 mag of visual extinction or greater toward the infrared object. Assuming that both K0210-1 and K0304-1 have the intrinsic colors of A-type stars, a limiting mag of 21 in the optical suggests at least 3 magnitudes of visual extinction for the source in NGC 5900; for a late-time observation, the source could be intrinsically much redder, requiring less or no extinction. Additional optical observations within a few months of the above observations would be useful to help to set limits on the extinction of each object.