04180-3826 HDS 546 is a typical case of a Hipparcos binary that has not been observed since its discovery in 1991. It has made one full revolution since, and the short arc observed at SOAR shows a rapid motion. This is a pair of K2V chromospherically active dwarfs.
05229-4219 TOK 93 Aa, Ab was first resolved in 2011 at Gemini-S (Tokovinin et al. 2012, Cat. J/AJ/144/7). It has a variable radial velocity and astrometric acceleration. Some observations have been reprocessed. The faint star B at 14''  is physical.
05542-2909 The orbit of FIN 382 with P=20.16 years given in (Tokovinin et al. 2015, Cat. J/AJ/150/50) is incorrect (Figure 1). The true period is 10 years. The revised orbit has a very high quality, with the rms residuals of 3.6 and 1.8mas in two coordinates.
08369-7857 KOH 79 is a young variable star EG Cha in the {eta} Cha association. Two preliminary orbits proposed by Koehler & Petr-Gotzens 2002AJ....124.2899K are now replaced by one non-ambiguous, though still preliminary, orbit. The dynamical parallax of 11.5mas matches the known distance to this association and may eventually help to measure it better.
09149+0427 HEI 350 is a nearby red dwarf pair GJ 390 (the spectral type of the primary is K4V). Despite the large {Delta}m, the first two micromemeter measures by W. Heintz in 1987 and 1988 have contradictory quadrants, and neither agrees well with the accurate measures available since 2003. The pair has not been resolved by Hiparcos, presumably because of the large {Delta}m. The orbit is only loosely constrained. The binary might be young and belong to the Castor moving group. Its secondary with V-I_C_=3.15mag is located above the main sequence in Figure 3; the large magnitude difference {Delta}V=4.0mag was confirmed in 2016.4.
09275-5806 The orbit of CHR 240 published in (Tokovinin et al. 2015, Cat. J/AJ/150/50) is substantially revised, with a new period of 1.42 years instead of 2.62 years. This very close pair is often under the diffraction limit of SOAR.
09466-4966 Our relative photometry implies that {Delta}I>{Delta}y, i.e., the secondary is bluer than the primary. The G5IV primary is evolved; it is located in the subgiant branch of the CMD. The Hipparcos photometry {Delta}Hp=1.24mag is suspect, because in 1991 the pair was very close, 0.15''.
09510-8004 HDS 1421 (B8IV) belongs to the Sco-Cen association; the dynamical parallax is 6.4mas. The orbit is still preliminary, but its curvature is well defined.
11102-1122 HDS 1590 (HD 97038) is a double-lined spectroscopic binary (D. Latham, 2012, private communication). Its corrected orbit is now well defined after coverage of the periastron.
13072-5420 Despite the drastic revision of the previous orbit, the elements of FIN 54 remain tentative, given that only a small arc is covered (Figure 1). One of the components is an eclipsing binary V949 Cen. The dynamical parallax is 4.8 mas, substantially larger than 1.3mas measured by Hipparcos.
13377-2337 Two orbits of RST 2856 (BD-22{deg} 3633) by Heintz 1997ApJS..111..335H with periods of 110 and 51.5 years are now replaced by the new, but still tentative orbit with P=122years. It is based on two HRCam measures and a handful of visual micrometer measures. The {Delta}y=2.1mag is derived from the very noisy data and is likely incorrect; the pair has not been resolved by Hipparcos despite its 0.3'' separation. The dynamical parallax is 12.3mas, and the matching spectral type of the primary is G5V.
13598-0333 This star HR 5278 (F6V) possibly contains a debris disk. A slight revision of the previous orbit by Horch et al. 2011AJ....141..180H leaves very well-defined elements. Both components are at about 1.5mag above the main sequence, while the mass sum is slightly larger than expected. The stars could have evolved off the main sequence or are still contracting.
14383-4954 A drastic revision of the orbit by Zirm (2014, IAUDS, 182, 1) changes the period of FIN 371 from 27.6 to 50.7 years.
14453-3609 The first tentative orbit for I 528, with a poor coverage and doubtful visual measures, is suggested. The formal errors of the elements are misleadingly small. The component C is at 4.5''. The dynamic parallax is 5.3mas, and the binary may belong to the Sco-Cen association.
14589+0636 WSI 81 (HIP 73314) is on the California planet search program (Isaacson & Fischer 2010, Cat. J/ApJ/725/875). The new orbit is well defined and leads to the mass sum of 2.2M_{Sun}_, while the dynamical parallax corresponds to 1.7M_{Sun}_. Both components are located on the main sequence.
15035-4035 The revision of the orbit by Heintz 1981ApJS...45..559H for I 1262 nearly doubles its period, from 134 to 251 years, but the orbit still remains preliminary and poorly constrained. The binary belongs to the Sco-Cen association, and its dynamic parallax is 5.7mas.
15042-1530 The new edge-on (i=89{deg}) orbit of RST 3906 is very different from the previous one by Heintz 1981ApJS...45..559H with i=129{deg}. The new orbit fits the speckle data well, but implies that many micrometer measures of this pair are totally incorrect (possibly observers confused it with another pair?). The pair was unresolved at SOAR on 2016.14 in agreement with the new orbit.
15282-0921 This nearby K2V star GJ 586 is a spectroscopic binary with a record-high eccentricity of e=0.976. Precise radial velocities from Strassmeier et al. 2013 (Cat. J/A+A/559/A17) constrain all spectroscopic elements very tightly, leaving for adjustment only the "visual" elements a, {Omega}, and i. The orbital parallax is 52.5+/-6.2mas, and the orbital masses are 0.86+/-0.11 and 0.58+/-0.08M_{Sun}_.
15290-2852 BU 1114 is a nearby dwarf with a physical tertiary component C at 9.6''. Some published non-resolutions of AB at SOAR refer in fact to this component C, pointed erroneously instead of AB. The edge-on orbit is preliminary and yields the mass sum of 2.0M_{Sun}_, less than 2.9M_{Sun}_ estimated from the luminosity.
15317+0053 TOK 48 (HIP 76031, HD 138369) is a single-lined spectroscopic binary with a period of 619.3 days (Griffin 2013Obs...133....1G). Resolved measures from SOAR are combined with the RVs of the primary component in the orbital fit. However, the solution converges to i{approx}180{deg}, contradicting the observed radial velocity variation. Therefore, in the combined speckle-spectroscopic orbit the inclination was fixed at 150{deg}. The differential photometry {Delta}y=1.6mag and {Delta}I=1.25mag leaves no doubt that the spectrum should contain double lines. However, Griffin could not find them, despite dedicated effort. His hypothesis that the secondary component is a close binary is not supported by the speckle photometry, but the secondary could have a fast axial rotation, reducing the depth of its lines in the blended spectrum. Both components are located on the main sequence.
15332-2429 CHR 232 Aa,Ab (HR 5765) is an A7V chemically peculiar binary (Abt & Morrell 1995, Cat. J/ApJS/99/135) with a new well-constrained 16.5 year orbit (rms residuals 1mas). A very similar orbit has just been published by Docobo et al. (2016, IAUDS, 189, 1). It has made more than one full revolution since its discovery in 1996.18. The visual companion B at 9.2'' is also a resolved as a close binary SEE 238 BC with a 60.4 year orbit; its observation with HRCam in 2008.54 in fact refers to the Aa,Ab pair. The two subsystems Aa,Ab and BC in this 2+2 quadruple are not co-planar. The dynamical parallaxes of Aa,Ab and BC are 9.4 and 10.3mas, respectively, while the HIP2 parallax is 10.4mas. The component Ab is located above the main sequence in the CMD.
15348-2808 The first preliminary 26 year orbit of TOK 49 Aa,Ab is computed. The outer binary RST 1847 AB has a separation of 1''.
15548-6554 The first orbit of the nearby red dwarf binary NZO 65 (G2V) is well constrained. Its components are on the main sequence.
16544-3806 This is a dramatic revision of the previous orbit of HDS 2392 by Tokovinin et al. 2015 (Cat. J/AJ/150/50).
17018-5108 The orbit of I 1306 by Olevic & Cvetkovic 2004A&A...415..259O with P=62.3 years is revised to P=194 years and still remains preliminary; only half of it has been covered in almost a century of observation. This is a bright star HR 6312, A9III. The mass sum of 1.0M_{Sun}_ does not match the spectral type, casting suspicion on the HIP2 parallax of 9.6mas (the dynamical parallax is 5.8mas).
17066+0039 After a slight correction, the orbit of the subsystem Ba,Bb with P=6.34years is now well constrained. The outer pair BU 823 AB has a poorly defined 532 year orbit. Coplanarity between the inner and outer orbits is not excluded.
17221-7007 A drastic revision of the orbit of FIN 373 (HR 6411, i Aps, B8/9V). Compared to the orbit by Docobo & Andrade 2013MNRAS.428..321D, even the direction of the rotation has changed from prograde to retrograde, see Figure 1. The published SOAR measure in 2009.26 was incorrect and corresponded to the image doubling caused by telescope vibration; it has been reprocessed. The rms residuals to the new orbit are 1.8mas, and it is now well defined.
17575-5740 The first 9 year orbit of the subsystem Ba,Bb is well constrained. The outer pair AB has a separation of 2.5'' and no orbit so far.
17584+0428 KUI 84 (GJ 9609, K8) is a nearby close triple system where the secondary component of the 14.7 year visual binary contains a 34.5 day spectroscopic subsystem (Tokovinin 1994AstL...20..309T). The secondary component is located above the main sequence in the CMD, as expected. Deviations of the speckle measures from the latest visual orbit by Docobo & Ling 2005IAUDS.155....1D prompted its slight revision here. Radial velocities were used together with the speckle measures, leading to a very well-defined orbit. The HIP2 parallax of 22.9mas corresponds to the mass sum of 2.0M_{Sun}_, while the orbital parallax of 26.3mas and the mass sum of 1.3M_{Sun}_ are a better match to the masses estimated by Tokovinin 1994AstL...20..309T.
18150-5018 The first orbit of I 429 (HD 166839, A0V) looks reasonable, but then the discovery measure by Innes in 1902.5 at a separation of 0.5'' must be totally incorrect. This and other measures made before 1929 were ignored in the orbit calculation. Currently, the pair is approaching periastron.
18368-2617 The new orbit of RST 2187 AB looks good, but corresponds to the mass sum of 1.4M_{Sun}_. A revision of the HIP2 parallax from 21.5+/-1.7mas to 19mas is needed to increase the mass sum of this pair of nearly equal G3V stars to 2M_{Sun}_. The tertiary component C at 12.6'' is physical.
18480-1009 HDS 2665 is a nearby K2V dwarf. The primary component is located on the main sequence, while the secondary is above it. The mass sum of 2.0M_{Sun}_ is somewhat larger than expected, so there may be inner subsystems.
19581-4808 Some observations of the nearby G0V dwarf binary HDS 2842 were reprocessed for a minor revision of its previous 32 year orbit, which is now definitive.
20217-3637 HDS 2908 (HD 193464, F8V) is another nearby dwarf binary. Double lines were noticed, but there is no spectroscopic orbit in the literature. The {Delta}y=0.49mag is based on two well-resolved observations and is more reliable than {Delta}Hp=0.21mag.
22116-3428 The 66 year first orbit of CHR 230 Aa, Ab (K1/K2III) is well defined. The outer binary AB has a separation of 0.9''. The large eccentricity e=0.93 of Aa, Ab could be caused by the Kozai-Lidov cycles. Both components are located on the giant branch in the CMD (Figure 3).