Seeing was predicted to be at or a little better than average, so I uncovered the 6-inch to observe. The 20-inch has a malfunctioning azimuth encoder, so out of action. I'll try cleaning the connectors to see if that fixes the intermittent encoder error, otherwise I'll have to tear the scope all the way down to tighten the encoder shaft set screw. For this night's session I chose pairs Burnham discovered with his 6-inch, and tested myself against him. I had trouble with some of the faintest stars as there was thin haze blowing in. Happy to be out observing; the scope has good optics so it's a pleasure to observe with it and the piggybacked 80mm.
BU 1 AB: 152; 120x: Amazing close triple in a nearly perfect triangle. -31% PRO, it is not binary, nor is C.
00h 52m 49.22s +56° 37' 39.5" P.A. 82.00 sep 1.5 mag 8.58,9.33 Sp O6.5V+B0V dist. 3030.3 pc (9884.84 l.y.)
BU 3 AB: 152; 180x: Very faint B swims into view with attention, well separated. -31% PRO it is not binary.
01h 17m 03.06s +56° 30' 15.1" P.A. 27.00 sep 4.5 mag 8.02,10.10 Sp K0
BU 5 AB: 152; 250x: Barely notched elongation, difficult. 1.5" at discovery, no problem for Burnham! No Gaia parallax for B. Given the amount of movement since discovery, an orbit should be tried.
01h 39m 15.21s +16° 37' 31.9" P.A. 282.00 sep 0.5 mag 6.98,9.20 Sp G3III dist. 177.62 pc (579.4 l.y.)
BU 107 AB: 152; 175x: Very faint B held after foveal coaxing, wide. 9% PRO, 4,203 AU WS, 2.1+1.8 Msol, and RVD 0.7 < EV 1.3, it's possible it's binary and an orbit should be tried.
00h 31m 17.66s +63° 20' 33.0" P.A. 354.00 sep 5.8 mag 11.14,11.73 dist. 276.24 pc (901.09 l.y.)
B 108 AB: 152; 175x: Well separated faint B. -19% PRO, it is not binary.
00h 34m 33.70s +62° 54' 12.2" P.A. 6.00 sep 4.5 mag 7.81,10.60 Sp F5 dist. 54.2 pc (176.8 l.y.)
BU 230 AB: 152; 175x: B seen with averted vision then can hold, well split. Lacks parallax data for the primary.
00h 37m 20.12s +27° 18' 12.0" P.A. 325.00 sep 3.9 mag 9.40,10.00 Sp F5
BU 231 AB: 152; 120x: Easy faint wide. -82% PRO it is not binary.
00h 44m 43.50s +48° 17' 03.8" P.A. 303.00 sep 34.4 mag 4.54,11.20 Sp B5IIIe dist. 215.52 pc (703.03 l.y.)
BU 232 AB: 152; 250x: Unequal, hairline spilt with seeing. 98%(!) PRO, 76 AU WS, 1.3+1.2 Msol, it is likely binary. SOC grade 3 orbit, 205-year period.
00h 50m 25.10s +50° 37' 49.6" P.A. 254.00 sep 0.9 mag 8.46,8.79 Sp F5 dist. 101.11 pc (329.82 l.y.)
BU 236 AB: 152; 120x: Near equal wide. 15% PRO, 1526 AU WS, 2.0+1.9 Msol, there is a possibility it is binary and an orbit can be tried.
01h 12m 04.85s +47° 00' 03.2" P.A. 114.00 sep 5.4 mag 9.10,9.20 Sp A0
BU 257 AB: 152; 250x: Orange and blue overlapping disks, with seeing only. Gaia lacks any data for secondary.
00h 40m 13.00s +47° 15' 21.0" P.A. 253.00 sep 0.6 mag 8.06,9.11 Sp G0 dist. 246.31 pc (803.46 l.y.)
BU 258 AB: 152; 250x: Closely split, very faint B, on A's diffraction line. -72% PRO, it is not binary.
01h 13m 09.82s +61° 42' 22.3" P.A. 263.00 sep 1.6 mag 6.50,8.80 Sp B9V dist. 201.61 pc (657.65 l.y.)
BU 394 AB: 152; 250x: Closely split unequal, 1 Dm. 10% PRO, only 20 AU WS, 1.0+1.0 Msol. Negative PMV 0.13 but to me that just means it could be in retrograde motion. Indeed, there is a SOC grade 3 orbit, 142-year period, which will widen ~0.2" in the next 20 years.
00h 30m 45.56s +47° 31' 47.5" P.A. 278.00 sep 0.9 mag 8.49,8.77 Sp G0 dist. 49.33 pc (160.91 l.y.)
BU 396 AB: 152; 250x: B is a faint small dot, steady in A's diffraction. Needed to use the peephole to see it. Gaia lacks data on the secondary. It would be worth trying an orbit given the difficulty, though the star is a bit far away to have a good chance.
01h 03m 37.01s +61° 04' 29.4" P.A. 68.00 sep 1.3 mag 6.06,8.62 Sp F0II dist. 613.5 pc (2001.24 l.y.)
BU 398 AB: 152; 175x: Unequal, very close split. -45% PRO, it is not binary.
01h 11m 52.40s +47° 47' 54.4" P.A. 44.00 sep 1.8 mag 9.31,9.38 Sp A2 dist. 201.61 pc (657.65 l.y.)
BU 453 AB: 152; 333x: Exceedingly difficult elongation, with flashes of split in best moments, unequal. Shockingly a -61% PRO, 53 AU WS, 0.9+0.8 Msol, -0.15 PMV. SOC grade 4 orbit 576- year period, which has tracked through a significant arc since discovery. It may well be binary but is very peculiar. 1.0" at discovery.
01h 45m 00.71s +57° 07' 00.3" P.A. 115.00 sep 0.8 mag 10.04,10.45 Sp G5 dist. 101.73 pc (331.84 l.y.)
BU 488 AB: 152; 250x: Very faint B seen intermittently, lightly blue. 74% PRO, 458 AU WS, 2.1+1.0 Msol, RVD 2.4 < EV 3.4, it is likely binary and needs an orbit.
00h 23m 59.82s -03° 28' 31.0" P.A. 340.00 sep 3.3 mag 7.41,10.28 Sp A2V dist. 131.93 pc (430.36 l.y.)
BU 492 AB: 152; 250x: B is a persistent small faint dot around 2" separation. No Gaia data on B.
00h 45m 17.20s +55° 13' 17.1" P.A. 173.00 sep 1.5 mag 5.42,11.50 Sp A2Vs dist. 98.81 pc (322.32 l.y.)
BU 507 AB: 152; 175x: Very faint B, well separated. 31% PRO, 1.8+1.0 Msol, it is possibly binary and needs an orbit.
01h 35m 26.61s +26° 41' 03.3" P.A. 145.00 sep 2.2 mag 8.05,10.89 Sp K2 dist. 129.87 pc (423.64 l.y.)
BU 508 AB: 152; 250x: Extremely difficult, elongated for sure and in best moments heavily notched unequal. No Gaia data for B, an orbit should be tried given the difficulty.
01h 39m 08.52s +26° 56' 08.0" P.A. 53.00 sep 0.7 mag 9.81,10.02 Sp F8
BU 509 AB: 152; 250x: Faint, very close split with seeing, nearly equal. 81% PRO, 35 AU WS, 0.8+0.9 Msol. SOC grade 3 orbit, 241-year period, little change in the next 20 years.
01h 43m 44.93s +09° 34' 07.2" P.A. 21.00 sep 0.8 mag 9.48,9.19 Sp K0 dist. 51.26 pc (167.21 l.y.)
BU 513 AB: 152; 250x: White, maybe a very slight out of roundness, not defined. SOC grade 2 orbit, 60.43-year period, it is due east now and will be due south by 2035, widening to 0.6". Discovered at 1.0" with the 18.5-inch Dearborn refractor. Burnham says: "This most interesting binary was discovered with the 18.5", but at the time was easily seen with the 6-inch. It is now (1898) a very difficult object, and only measurable with a large aperture under the best conditions. The motion of the companion has been nearly a quadrant since the first measures, and it may prove to have a short period, but a much larger arc is required to give even a rough approximation of the orbit." Discovery was due west near apastron; it is now due east periastron. 1898 was almost exactly 2 orbits ago, so I'm trying to observe it when Burnham says it's difficult and needs large aperture!
02h 01m 57.55s +70° 54' 25.4" P.A. 320.00 sep 0.6 mag 4.65,6.74 Sp A3V dist. 35.26 pc (115.02 l.y.)
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