04312+5858 STI2051 AB   Component A is an astrometric binary with a period of 23years and a semimajor axis of 0.070'' (Strand 1977AJ.....82..745S). Let it be assumed that both components, A and B, are at the same heliocentric distance and have a similar proper motion, as can be found in SIMBAD and in the literature. Then the tangential velocities for both components are almost equal, but the radial ones as given in SIMBAD, differ significantly (for component A it is 29+/-4km/s, for B 2+/-9.8km/s). With these values, we obtain a specific kinetic energy of relative motion of 367.5km^2^/s^2^, whereas the upper limit for the potential is 25km^2^/s^2^. For the smallest radial velocity difference (25 and 12km/s), we obtain a specific kinetic energy of 85km^2^/s^2^. Since the potential is significantly smaller than the specific kinetic energy, this is not in favor of the pair being bound. Also, the measurements show a linear trend and we calculated the linear solution for this pair.
17046+3900 HJ 2804 AB   The catalog magnitude difference between the components of the pair is 2.3mag, i.e., the apparent magnitudes given in the WDS are 11.0mag and 13.3mag. We measured a much smaller magnitude difference (0.59mag in V filter and 0.64mag in B filter). The magnitude differences given by other observers (in the Washington Database) are similar to our values.
18489+1615 STF2400 A-BC The pair A-BC belongs to a multiple system that has four components. The relative coordinates of the pairs AB, A-BC, and AC are presented in Figure 5. As can be seen, the values are similar and almost the same for pairs AB and A-BC after 2000. The reason for this is a small separation between components B and C. During 100years of observing pair BC, its relative coordinates are almost constant. The angular separation is about 0.8 arcsec and the position angle is about 200{deg}. In our opinion, there is a high probability that there exist measurements that have not been assigned to the proper pair. We could not visually resolve the components B and C. Because of all this, our measurements refer to pair A-BC.