Saturday, October 16, 2021

15 october 2021

It was an astronomy filled day yesterday.  From 11am to noon I watched the sun through the 6-inch refractor, both white light (one large spot foreshortened and stretched on the limb with crazed cracks around it, and more cracks elsewhere) and in H-alpha, with many interesting prominences like electric forests.  It is dark early now, 7:30pm, so again with the 6-inch I viewed Saturn, Jupiter, and the moon in their turn as they culminated (they were all on an arc not far from each other).  Great views and good contrast despite a thin marine haze blowing in.  The marine haze spoiled the night a little and I wished I was at a higher elevation, but it was still good enough to continue with some double stars.  Seeing was predicted to be good so I opened the 20-inch and from 9-11pm tried my luck.  The haze shrouded very faint stars but I did observe some interesting pairs.  Seeing was variable and I found myself putting on and removing the mask as conditions dictated.  I stayed pointed just west of meridian, in Cygnus, to avoid roof currents.

STF2610 AB: 508; 205x: Wide, white, near equal.  Not physical. 
19h 59m 07.47s +35° 32' 10.1" P.A. 296.00 sep 4.3 mag 8.76,9.24 Sp B9V dist. 358.42 pc (1169.17 l.y.)

A   719 AB: 508; 205x: Well split, noticeably unequal stars, A is light orange.  WDS uncertain, however there is no overlap in their parallax ranges, -34%
20h 00m 16.61s +46° 20' 19.0" P.A. 109.00 sep 3.0 mag 9.90,10.43 Sp A0

STT 394 AB: 508; 205x: Wide, 3 delta mag light yellow A and blue B, pretty.  WDS says physical, and there is 28% overlap in their parallax ranges, 2,011 AU weighted separation, 2.77/1.22 Msun, so possible it is gravitational.
20h 00m 11.43s +36° 24' 50.8" P.A. 294.00 sep 11.0 mag 7.14,10.27 Sp K1III dist. 152.44 pc (497.26 l.y.)

BU  439 AB: 508; 205x: Not easy, I can just see B with direct vision, very faint and rather closely split to light yellow A.  WDS uncertain, and unfortunately there is no parallax range overlap, -52%.  Burnham discovered with the Dearborn 18.5-inch. 
20h 00m 46.25s +29° 49' 19.4" P.A. 222.00 sep 3.3 mag 7.89,12.70 Sp G0V

STF2619 AB: 508; 205x: Pale yellow-white stars, well split, near equal.  Several other wider pairs.  WDS says physical.  My calculator says there is a -1% parallax range overlap, but all the upper and lower limits are 54 parsecs, and there is only 226 AU weighted separation with 0.99/0.98 Msun, so this very possibly is gravitational. 
20h 01m 01.69s +48° 15' 28.5" P.A. 239.00 sep 4.0 mag 8.91,8.92 Sp G5 dist. 60.02 pc (195.79 l.y.)

BU  426 AB: 508; 205x: Part of a neat double-double with BU 427 CD, all of which Burnham discovered with the 6-inch.  Equilateral triangle of equal magnitude stars, two of which are doubles which look very similar, both with 2 delta mag companions but one with twice (BU 426) the still close separation as the other (BU 427).  Their PAs are about 45-degrees different, each pointed away from the third star in the triangle which unfortunately is not double.  WDS says this one is not physical, but they're wrong: 44% parallax range overlap, 995 AU weighted separation, 1.94/1.20 Msun -- points to gravitational.  If they rejected based on proper motion they may not have considered the direction of the orbit...
20h 02m 07.92s +54° 38' 28.0" P.A. 307.00 sep 5.9 mag 8.53,10.50 Sp K0

BU 427 CD: 508; 205x: Double-double with BU 426.  WDS says not physical, and there is -16% parallax range overlap, so it is not (and the radial velocity delta exceeds the escape velocity anyway).
20h 02m 22.85s +54° 40' 07.5" P.A. 336.00 sep 3.1 mag 8.39,10.18 Sp F2III

HO  454 AB: 508; 205x: B visible with averted vision, wide, 4 delta mag.  WDS says physical, and there is 0% overlap in their parallax ranges, 1,295 AU weighted separation, and 2.51/1.05 Msun, so could be gravitational. 
20h 03m 13.50s +50° 27' 53.7" P.A. 53.00 sep 5.9 mag 7.55,11.36 Sp A0 dist. 194.55 pc (634.62 l.y.)

A  1413 AB: 508; 205x: Pretty tough in a dense field of faint stars, closely separated and 1 delta mag.  WDS uncertain, but it is likely gravitational: 78% parallax range overlap, 1,376 AU weighted separation, 2.46/1.99 Msun.
20h 04m 34.48s +36° 40' 49.1" P.A. 139.00 sep 2.4 mag 9.97,10.60 Sp A7V

STH    A: 508; 205x: Near equal fairly well separated -- I don't find any matches for this in WDS.  This is H. Struve, whom I am guessing is Hermann, Otto's uncle.  

BU 1480 AB: 508; 205x: White A and 2 delta B, well separated.  WDS says not physical, and I can't find the companion in Gaia.
20h 05m 09.84s +38° 57' 06.1" P.A. 328.00 sep 8.2 mag 9.22,11.40 Sp A3

BU 1481 AB: 508; 205x: Faint and very wide   i wonder at the interest, proper motions? WDS says not physical
20h 05m 09.78s +38° 28' 42.4" P.A. 240.00 sep 42.7 mag 6.17,13.20 Sp G3V dist. 18.79 pc (61.29 l.y.)

BEW 3: AB: 508; 205x: B is just on edge of detectability, very busy filed.  Not physical.  Bastian, U., Eisloeffel, J., & Wiese, K., a German amateur group.  Not physical.
19h 44m 19.61s +30° 20' 45.5" P.A. 302.00 sep 11.5 mag 11.80,12.50

GYL  23 AB: 508; 205x: Very faint wide B.  Not physical.
20h 06m 32.99s +33° 02' 17.0" P.A. 180.00 sep 13.3 mag 10.97,12.05 Sp F5

STT 398 AB: 158; 445x: With clear disks and still a bit wavering seeing, I can split this nicely, the stars are 2 delta mag, dull blue-white A and blue B.  Spectral class O9.5III+ (blue).  WDS uncertain, but they likely are not gravitational: -28% parallax range overlap.  
20h 07m 23.69s +35° 43' 05.9" P.A. 82.00 sep 1.0 mag 7.45,9.20 Sp O9.5III+ dist. 628.93 pc (2051.57 l.y.)

A  1416 AB: 178; 205x: B emerges to view with averted vision and foveal coaxing, really nice, 3 delta mag, well separated around 5".  WDS uncertain, but it is not likely gravitational: -71% parallax range overlap.
20h 07m 34.39s +38° 37' 51.5" P.A. 42.00 sep 4.7 mag 8.34,11.20 Sp A3V

A   382 AB: 178; 445x: A bit difficult, A is fairly bright, B is significantly fainter and resolves with seeing, fairly well separated around 2".  WDS calls it physical, but there is -37% parallax range overlap. 
20h 08m 01.18s +42° 23' 06.0" P.A. 96.00 sep 1.7 mag 7.21,9.49 Sp K0 dist. 200.4 pc (653.7 l.y.)

A   721 AB: 508; 205x: Large magnitude difference of 3 delta, white stars, well split.  WDS uncertain, but there is -88% parallax range overlap, no not physical.
20h 08m 27.15s +46° 22' 29.6" P.A. 43.00 sep 4.0 mag 8.42,11.52 Sp Am dist. 393.7 pc (1284.25 l.y.)

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