Tifft's smallest redshift quantum, 2.88 km/s or thereabouts, occurs not only with galaxies, but also with stars and HII regions in our galaxy. I checked whether red/blueshifts (apparent radial velocities, a.k.a. RV's) of stars in various constellations were equally distributed modulo 3. Using Dibon-Smith's small catalog (Wiley, 1992), which gives RV's to 1 km/s, I found that constellations near l=0,90,180 & 270 (and b=0), tended to have unequal, though nonsignificantly so, RV distributions mod 3. Combining all four directions gave statistical significance.
Then I made a periodogram using Robinson & Muirden's very small catalog, which gives RV's to 0.1 km/s. It contains the 286 brightest stars in the sky, excerpted from RE Wilson's 1953 Carnegie catalog. I considered only the 22 stars located near the above directions, namely, R.A. 17h to 18h30' and Decl. -20 to -40 and its antipode, and 20h30' to 22h and +40 to +60 and its antipode. The brightest stars tend to be nearby, so spatial trends in stellar velocity affect their RV's less. They tend to be massive, so binary orbits affect their RV's less. At the positions chosen, Oort's law red/blueshifts are approximately zero.
The periodogram showed a strong family of peaks at 10.9, 5.55, and 2.72 km/s. Those who would confirm this, should look at nearby non-binary stars in the abovementioned windows of sky.
My sample of 425 stars from Dibon-Smith's list, near the apex and antapex (corrected for the mean RV of the patch), and near the intersection of the Milky Way with the equator of the apical sphere (uncorrected)(and possibly in the entire Milky Way), clearly showed an excess of RVs 65-70 km/s. Astronomers have attributed that phenomenon to causes other than quantized redshift. Only four of Dibon-Smith's entire 2400-star list had RVs (roughly corrected for apex motion) greater than 110: 144(=72*2), 154, 180 and 304(72*4=288). The two former were in the 168-star apex/antapex patches.
Blitz, Fich & Stark (Astrophysical J. Supplement 49:183-206, 1982) used radio emissions of carbon monoxide to measure RV's of HII regions in our galaxy. Using my same sky windows, I made a periodogram for the 31 HII regions whose RV's were stated to < 1.0 km/s accuracy. (One trio and two duos of regions were so close in position and RV, that I merged them, netting 27 regions.) Then I augmented these by including the 22 regions whose RV's were less accurate, and made another periodogram. The first, second and third most valid peaks, by size and consistency, were 2.36, 2.59; and 4.5(+/-) 0.2 km/s.
Substituting mean orbital speed (calculated from semimajor axis, eccentricity and orbital period) for RV, I made a periodogram for the 61 planets, asteroids and moons listed in WK Hartmann, "Moons & Planets", 2nd ed., 1983, Appendix. The most prominent peaks (excluding the oscillatory region below about 1.1 km/s) were 14.27, 7.34 and 2.63 km/s.
Tifft's small period is most prominent between the large moons of Jupiter and Saturn, and (doubled) between the inner planets. The differences in orbital speed of Jupiter's 2nd&3rd and 3rd&4th large moons are 2.85 and 2.68 km/s. Saturn's 1st&3rd, 3rd&4th and 4th&5th large (>1000 km dia.) moons differ 2.87, 2.91 and 2.31 km/s. Venus&Earth differ 5.22=2*2.61; Earth&Mars differ 5.70=2*2.85. So, diverse objects in our galaxy and solar system show approx. 2.5 km/s quantization.
