4 march 2021

Last night's transparency was predicted to be poor, but it wasn't too bad, so I'm glad I opened up.  Seeing was strangely variable.  I found myself switching between the 7-inch mask and full aperture, though I could not get magnification beyond 533x.  I ended up snagging a couple short period pairs, so it was a night well worth the effort.  It was cold, with some dew.  I seem to tap out all the doubles accessible to a 7-inch in Gemini, so I swung over to Ursa Major, though in this direction there were roof currents and even multiple jet aircraft on landing approach to Oakland airport which went near to or through my field of view, disturbing the air for minutes at a time. 

STF 830 AB: 178; 205x: Dim pair for a Struve, slightly red color near equal stars, wide, part of a neat triangle with a slightly fainter star making the third (AC).  Not physical
06h 03m 26.56s +27° 38' 32.7" P.A. 264.00 sep 11.4 mag 8.90,9.55 Sp F2

J 728 AB: 178; 205x: Dim pair, 1 delta mag, around 3".  Physical.
07h 06m 05.16s +19° 03' 11.7" P.A. 73.00 sep 3.0 mag 8.80,10.39 Sp G5

STF1017 AB: 178; 205x: White stars, near equal, wide.  Physical
07h 07m 10.44s +16° 50' 21.8" P.A. 255.00 sep 12.8 mag 9.32,10.25 Sp G+F8

STF1027 AB: 178; 205x: Near equal, pale white stars, wide.  Physical 
07h 08m 46.74s +16° 54' 31.8" P.A. 356.00 sep 6.9 mag 8.47,8.69 Sp K3III dist. 312.5 pc (1019.38 l.y.)

HO 518 AB: 508; 205x: Bright white and pale white, 2 delta mag, 3" separation.  A nice pair in a string of stars.

07h 10m 24.17s +30° 21' 31.7" P.A. 146.00 sep 3.3 mag 8.34,10.30 Sp A2

TDS4557 AB: 508; 533x: Very fine hairline split with seeing, dull white stars.
07h 10m 58.01s +27° 46' 52.3" P.A. 122.00 sep 0.5 mag 10.65,10.65

BU 1009 AB: 508; 205x: B is a very fine point on the edge of bright A' yellow-orange diffraction, subtle.  Burnham writes: "This fine and difficult pair was discovered at Mt. Hamilton with the 12-inch in 1881….The measures are sufficient to show from the common proper motion that this is a physical pair."  Discovered at 1.8" separation.
07h 11m 08.39s +30° 14' 43.0" P.A. 163.00 sep 1.8 mag 4.41,11.00 Sp K2III dist. 98.43 pc (321.08 l.y.)

STF1035 AB: 508; 205x: Very easy bright white equal pair.  Physical.
07h 12m 01.06s +22° 16' 44.5" P.A. 40.00 sep 8.7 mag 8.09,8.38 Sp F7IV dist. 163.67 pc (533.89 l.y.)

WEI 14 AB: 508; 205x: Very pretty white stars, 2 delta and about 3" separation, in a rich field
07h 12m 48.16s +15° 10' 41.9" P.A. 160.00 sep 2.1 mag 7.77,8.91 Sp B9.5IV dist. 1351.35 pc (4408.1 l.y.)

STF1037 AB: 178; 205x: Hairline split at 205x but went to 533 to get clear view of it to drift through the field to tell PA.  Slight magnitude difference.  Really nice looking pair, masked down to 7-inches to get clean disks.  Physical with a 118.35-year period, it will close rapidly and become undetectable during the 2030s, widening again in the 2040s.
07h 12m 49.08s +27° 13' 30.2" P.A. 302.40 sep 0.8 mag 7.24,7.27 Sp F8V dist. 42.48 pc (138.57 l.y.)

BU 22 AB: 178; 205x: Wide and uninteresting 2 delta mag.
07h 33m 14.80s +32° 51' 42.6" P.A. 151.00 sep 6.3 mag 8.56,10.90 Sp G5

STF1110 AB: 178; 205x: Castor.  A is a very pale yellow and B is yellow-green, 2 delta mag, very bright, pretty wide,  some fainter stars about.  Physical with a 459.8-year period.
07h 34m 35.86s +31° 53' 17.8" P.A. 52.10 sep 5.4 mag 1.93,2.97 Sp A1V+A4Vm dist. 15.6 pc (50.89 l.y.)

HJ 425 BC: 178; 205x:  A component of STF1113 AB. A is light yellow-orange, BC is widely separated from A, itself a pretty wide pair of blue stars.  Physical.

07h 34m 59.31s +24° 14' 23.5" P.A. 46.00 sep 8.5 mag 11.10,11.40

AG 142 AB: 178; 205x: Very fine close pair, 1 delta mag, B brightens with averted vision but can see it direct.
07h 41m 26.46s +23° 11' 40.7" P.A. 21.00 sep 1.7 mag 9.81,10.45 Sp A5

AG 144 AB: 178; 205x: Wide white stars, significant delta mag, B brightens with averted vision.  Not physical
07h 51m 54.12s +22° 15' 26.5" P.A. 334.00 sep 11.6 mag 9.73,11.14 Sp F5

A 2536 AB: 178; 333x: Very significant delta mag, very close, it's an elongated haze until seeing settles then can I can resolve and split the faint B from white A 
07h 54m 36.67s +25° 12' 48.4" P.A. 309.00 sep 0.9 mag 10.36,10.57 Sp G0 dist. 485.44 pc (1583.51 l.y.)

STF1158 AB: 178; 205x: Dim for a Struve, wide, one delta mag.  Not physical
07h 56m 31.40s +21° 52' 28.6" P.A. 334.00 sep 7.6 mag 9.30,9.30 Sp A5III

STF1242 AB: 178; 205x: Dim pair for Struve, half delta mag, well split about 4".
08h 36m 01.43s +47° 07' 29.6" P.A. 175.00 sep 2.7 mag 9.93,10.49 Sp F0

STF1258 AB: 178; 205x: White stars, wide, near equal.  Physical
08h 43m 25.41s +48° 51' 41.9" P.A. 331.00 sep 10.1 mag 7.72,7.87 Sp F0 dist. 143.47 pc (468 l.y.)

KR 30 AB: 178; 205x: Finely split equal white stars, need to wait for seeing to settle for the elongation to resolve to points, about 2", small scale.  
08h 46m 49.82s +57° 41' 55.7" P.A. 305.00 sep 1.9 mag 10.26,10.32 Sp G5

STF1271 AB: 178; 205x: Very close, barely split, around 1", more than 1 delta magnitude 
08h 50m 07.39s +56° 12' 23.7" P.A. 81.00 sep 0.9 mag 9.46,10.28 Sp F5 dist. 149.25 pc (486.85 l.y.)

STF1278 AB: 178; 205x: White A star and two delta mag, very wide B
08h 50m 42.68s +49° 20' 49.0" P.A. 128.00 sep 8.5 mag 8.54,10.50 Sp F5

STF1275 AB: 178; 205x: Neat near equal, nice split about 2", white
08h 51m 26.19s +57° 31' 38.1" P.A. 198.00 sep 1.9 mag 8.68,8.87 Sp F0 dist. 194.55 pc (634.62 l.y.)

A 1584 AB: 508; 333x: Tight white stars, seeing is not very good but can still split it.  It has a noticable magnitude difference, however I need to guess which one is A.  I am able to estimate PA by drifting it across the field.  [My PA is in the correct line but my A and B are reversed.]  70.89-year period, it is now at apastron and will make a very small turn in its arc by 2040.
08h 53m 08.05s +54° 57' 11.0" P.A. 97.20 sep 0.7 mag 8.99,7.72 Sp G0 dist. 52.11 pc (169.98 l.y.)

ARG 71 AB: 508; 205x: White and wide
08h 54m 39.34s +49° 54' 09.9" P.A. 339.00 sep 5.3 mag 10.24,10.36 Sp G5

BU 408 AB: 178; 205x: A fine pair, white bright A and faint B about 3", 3 delta mag 
08h 59m 00.62s +63° 25' 42.8" P.A. 345.00 sep 2.8 mag 7.35,9.59 Sp G5 dist. 196.46 pc (640.85 l.y.)

HU 720 AB: 178; 333x: Suspected at 205x, it is the finest hairline split at 333x, slight magnitude difference, with seeing.   
09h 03m 16.01s +47° 40' 18.1" P.A. 136.00 sep 0.8 mag 8.62,9.27 Sp F5 dist. 152.44 pc (497.26 l.y.)

STF1312 AB: 178; 205x: White stars, wide, 1 delta mag.  Not physical
09h 10m 18.19s +52° 23' 05.7" P.A. 147.00 sep 4.7 mag 8.35,8.80 Sp F2V dist. 952.38 pc (3106.66 l.y.)

STF1318 AB: 178; 205x: Very pretty and delicate pair, 2 delta mag and about 2" separation, white stars
09h 13m 38.79s +46° 59' 25.3" P.A. 227.00 sep 2.6 mag 7.85,9.51 Sp F8V dist. 52.44 pc (171.06 l.y.)

STT 199 AB: 178; 205x: An excellent pair, B is a very fine four delta point well separated from bright white A. 
09h 20m 43.76s +51° 15' 57.8" P.A. 142.00 sep 5.6 mag 6.19,10.00 Sp F5V dist. 27.45 pc (89.54 l.y.)

STF1331 AB: 205x: Fine hairline split with seeing at 205x, better split at 333x, almost 1 delta mag, a very fine pair.  Three other faint stars appear with averted vision, and can then barely hold them direct, all nearby and arranged in a right angle to A with two of them on one side.  These are C, D, and E.
09h 20m 46.02s +61° 20' 58.4" P.A. 153.00 sep 0.9 mag 8.54,8.74 Sp A8IV dist. 206.61 pc (673.96 l.y.)

STF1340 AB: 178; 205x: Very nice, 2 delta mag white stars, wide, makes an attractive scene
09h 22m 32.22s +49° 32' 41.4" P.A. 319.00 sep 6.3 mag 7.08,8.99 Sp B9.5V dist. 226.24 pc (737.99 l.y.)

STF1346 AB: 178; 205x: Easy 1 delta mag pair, pretty wide.  Physical
09h 25m 37.88s +54° 00' 57.5" P.A. 314.00 sep 5.8 mag 7.69,8.59 Sp A2V dist. 196.08 pc (639.61 l.y.)

STF1359 AB: 178; 205x: Dim for a Struve, 1 delta mag, pretty wide, white stars.  Not physical.

09h 32m 58.20s +56° 14' 59.1" P.A. 54.00 sep 7.5 mag 9.77,10.76 Sp G5