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Neil Webster, St Marys Platt, Kent TN15 8NF
Introduction
The following measurements (Table 1) were made throughout 2019 using a Meade 12mm astrometric illuminated reticle eyepiece plus 2.5x powermate attached to an Altair Astro 115mm triplet refractor (focal length 805mm, f7). The total magnification was 167.5x with a field of view of 0.3 degrees.
All final separation values were calculated from a calibration determined by the timing/transit method (Simple Techniques of Measurement: E.T.H. Teague, Chapter 12 in Observing and Measuring Visual Double Stars ed. Argyle, pub. Springer). This was performed at the start of the year and gave a final value of 12.53 +/- 0.01 arc-seconds per division on the reticle measurement scale.
Position Angle measurements were made using the now tried and tested method previously outlined in DSSC 25 which involves using the directional west arrow on the synscan handset to electronically steer the primary to the outer edge of the protractor scale. This enables repeated measurements to be made with ease without having to disable the tracking of the mount.
As before, 10 separation and 10 position angle measurements (N = 20) were performed on the same evening for each pair and the final results and associated uncertainties later calculated.
Extensive use was again made of the Astroplanner software. Separations throughout this year were all limited to a range from 15 to 70 arc-seconds. As in previous years magnitudes ranged from 0.5 to 8.5.
As most of these systems are comparatively wide the orbits are generally very long (1,000 years+) and, as a result, very few have attempted orbit calculations. Residuals (from the online version of 6th USNO Catalogue of Orbits of Visual Binary Stars) have, however, been given for the few systems calculated but none have a better than grade 4 certainty (Table 2).
Values from the Fourth Catalogue of Interferometric Measurements have provided a more extensive set of residuals but most of these are from 1991 which is 28 years before the author’s measurements. Although many of the systems have not changed in this time-interval some have and, in certain cases, this may possibly explain the larger residuals calculated (Table 3).
For the systems with larger residuals, alternative values have been calculated using the latest WDS measurements (mostly 2018) for comparison. As can be seen many of the residuals calculated from the more recent WDS figures are smaller. This would seem to imply measurable PA and separation changes to these systems over relatively short timescales (27 years maximum) which is surprising when the possible orbital periods are potentially in orders of thousands of years (Table 4).
References:
The Cambridge Double Star Atlas, (Mullany J. Tirion W. pub. Cambridge)
Observing and Measuring Visual Double Stars (ed. Argyle R.W. pub. Springer)
Washington Double Star Catalogue (Mason, B.D., Wycoff, G.L. & Hartkopf, W.I.):
http://ad.usno.navy.mil/proj/WDS
Sixth Catalogue of Orbits of Visual Binary Stars (Hartkopf, W.I., Mason, B.D. & Worley, C.E.):
http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6/sixth-catalog-of-orbits-of-visual-binary-stars
Fourth Catalogue of Interferometric Measurements of Binary Stars:
http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/int4
Astroplanner:
http://www.astroplanner.net/
Table 1: Measurements
|
Pair
|
Comp
|
RA
|
Dec
|
Va
|
Vb
|
PA (o)
|
+/-
|
Sep (‘’)
|
+/-
|
Epoch
2019 +
|
N
|
Obs
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
S 457
|
AB
|
04531
|
-0117
|
7.93
|
8.07
|
354.0
|
0.1
|
40.8
|
0.2
|
.112
|
20
|
WST
|
|
STF 612
|
AB
|
04543
|
+0722
|
8.33
|
8.41
|
199.4
|
0.1
|
15.3
|
0.2
|
.112
|
20
|
WST
|
|
SHJ 49
|
AB
|
04590
|
+1433
|
6.06
|
7.43
|
306.0
|
0.1
|
39.0
|
0.1
|
.112
|
20
|
WST
|
|
STF 627
|
AB
|
05006
|
+0337
|
6.59
|
6.95
|
260.0
|
0.1
|
21.9
|
0.2
|
.112
|
20
|
WST
|
|
BVD 50
|
AB
|
05092
|
+1130
|
8.35
|
8.49
|
104.0
|
0.1
|
31.1
|
0.3
|
.112
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 696
|
AB
|
05228
|
+0333
|
4.95
|
6.76
|
28.5
|
0.1
|
32.0
|
0.2
|
.112
|
20
|
WST
|
|
STF 697
|
AB
|
05235
|
+1602
|
7.27
|
8.10
|
287.0
|
0.1
|
25.4
|
0.2
|
.123
|
20
|
WST
|
|
STF 734
|
AC
|
05331
|
-0143
|
6.67
|
8.35
|
243.0
|
0.1
|
29.2
|
0.2
|
.123
|
20
|
WST
|
|
STF 747
|
AB
|
05350
|
-0600
|
4.70
|
5.51
|
224.3
|
0.1
|
36.3
|
0.1
|
.123
|
20
|
WST
|
|
STF 855
|
AB
|
06090
|
+0230
|
5.68
|
6.68
|
114.6
|
0.1
|
29.1
|
0.2
|
.295
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 1062
|
AB
|
07229
|
+5517
|
5.76
|
6.71
|
316.9
|
0.1
|
13.8
|
0.1
|
.295
|
20
|
WST
|
|
STF 1315
|
AB
|
09128
|
+6141
|
7.33
|
7.65
|
27.8
|
0.1
|
25.1
|
0.1
|
.295
|
20
|
WST
|
|
STF 1321
|
AB
|
09144
|
+5241
|
7.79
|
7.88
|
98.2
|
0.1
|
16.7
|
0.2
|
.295
|
20
|
WST
|
|
STF 1369
|
AB
|
09354
|
+3958
|
6.98
|
7.98
|
149.8
|
0.1
|
25.1
|
0.1
|
.295
|
20
|
WST
|
|
STF 1415
|
AB
|
10178
|
+7104
|
6.65
|
7.27
|
168.0
|
0.1
|
16.5
|
0.2
|
.295
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 1603
|
AB
|
12081
|
+5528
|
7.82
|
8.26
|
84.0
|
0.1
|
22.6
|
0.1
|
.295
|
20
|
WST
|
|
STF 2241
|
AB
|
17419
|
+7209
|
4.60
|
5.59
|
14.0
|
0.1
|
29.6
|
0.2
|
.295
|
20
|
WST
|
|
STTA 163
|
AB
|
17563
|
+6237
|
7.77
|
7.59
|
52.6
|
0.1
|
54.1
|
0.2
|
.298
|
20
|
WST
|
|
STF 2273
|
AB
|
17592
|
+6409
|
7.31
|
7.63
|
282.3
|
0.1
|
22.6
|
0.1
|
.298
|
20
|
WST
|
|
STF 2308
|
AB
|
18002
|
+8000
|
5.70
|
6.00
|
232.0
|
0.1
|
18.7
|
0.1
|
.358
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 2278
|
AB
|
18029
|
+5626
|
7.78
|
8.14
|
28.9
|
0.2
|
36.3
|
0.1
|
.358
|
20
|
WST
|
|
STF 2420
|
AB
|
18512
|
+5923
|
4.77
|
8.26
|
316.0
|
0.2
|
37.6
|
0.1
|
.358
|
20
|
WST
|
|
SHJ 286
|
AB
|
19050
|
-0402
|
5.52
|
6.98
|
211.3
|
0.1
|
39.6
|
0.2
|
.701
|
20
|
WST
|
|
STF 2497
|
AB
|
19200
|
+0535
|
7.73
|
8.49
|
356.0
|
0.1
|
29.3
|
0.2
|
.701
|
20
|
WST
|
|
STFA 43
|
AB
|
19307
|
+2758
|
3.19
|
4.68
|
54.3
|
0.1
|
35.2
|
0.3
|
.703
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 2549
|
AD
|
19312
|
+6319
|
8.34
|
8.03
|
268.5
|
0.1
|
55.8
|
0.2
|
.358
|
20
|
WST
|
|
ARN 82
|
AB
|
19364
|
+3541
|
8.10
|
8.43
|
33.0
|
0.1
|
43.9
|
0.1
|
.717
|
20
|
WST
|
|
STFA 46
|
AB
|
19418
|
+5032
|
6.00
|
6.23
|
131.7
|
0.2
|
39.5
|
0.2
|
.717
|
20
|
WST
|
|
H 5 137
|
AB
|
19459
|
+3501
|
6.22
|
8.18
|
25.0
|
0.1
|
38.8
|
0.1
|
.717
|
20
|
WST
|
|
STFA 48
|
AB
|
19534
|
+2020
|
7.14
|
7.34
|
147.0
|
0.1
|
41.7
|
0.2
|
.703
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 2594
|
AB
|
19546
|
-0814
|
5.65
|
6.35
|
171.0
|
0.1
|
36.3
|
0.1
|
.701
|
20
|
WST
|
|
SHJ 314
|
AF
|
20060
|
+3547
|
6.78
|
7.30
|
28.0
|
0.1
|
36.3
|
0.1
|
.717
|
20
|
WST
|
|
WEB 12
|
AB
|
20078
|
+1950
|
8.36
|
8.37
|
77.0
|
0.1
|
40.1
|
0.1
|
.703
|
20
|
WST
|
|
S 738
|
AB
|
20106
|
+3338
|
7.76
|
8.43
|
106.0
|
0.1
|
42.6
|
0.1
|
.717
|
20
|
WST
|
|
S 735
|
AB
|
20113
|
-0008
|
7.16
|
7.98
|
211.0
|
0.1
|
56.4
|
0.1
|
.701
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
S 740
|
AB
|
20142
|
+0635
|
7.77
|
8.06
|
192.2
|
0.1
|
43.9
|
0.1
|
.701
|
20
|
WST
|
|
STF 2664
|
AB
|
20196
|
+1300
|
8.07
|
8.34
|
321.0
|
0.1
|
27.1
|
0.2
|
.703
|
20
|
WST
|
|
STF 2687
|
AB
|
20264
|
+5638
|
6.37
|
8.31
|
117.5
|
0.1
|
25.1
|
0.1
|
.722
|
20
|
WST
|
|
S 749
|
AB
|
20275
|
-0206
|
6.76
|
7.51
|
188.9
|
0.1
|
60.1
|
0.3
|
.703
|
20
|
WST
|
|
STF 2691
|
AB
|
20297
|
+3808
|
8.14
|
8.45
|
32.0
|
0.1
|
16.3
|
0.1
|
.722
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
STF 2690
|
A BC
|
20312
|
+1116
|
7.12
|
7.39
|
256.0
|
0.1
|
18.5
|
0.1
|
.703
|
20
|
WST
|
|
STF 2703
|
AB
|
20368
|
+1444
|
8.35
|
8.42
|
290.0
|
0.1
|
25.1
|
0.1
|
.703
|
20
|
WST
|
|
STF 2758
|
AB
|
21069
|
+3845
|
5.20
|
6.05
|
153.8
|
0.1
|
31.7
|
0.2
|
.722
|
20
|
WST
|
|
STF 2769
|
AB
|
21105
|
+2227
|
6.65
|
7.42
|
299.0
|
0.1
|
18.8
|
0.1
|
.703
|
20
|
WST
|
|
STT 447
|
AE
|
21395
|
+4144
|
7.67
|
8.48
|
42.8
|
0.2
|
29.1
|
0.2
|
.722
|
20
|
WST
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
S 800
|
AB
|
21538
|
+6237
|
7.07
|
7.91
|
145.0
|
0.1
|
62.7
|
0.1
|
.358
|
20
|
WST
|
|
ARY 45
|
AB
|
22083
|
+6959
|
7.86
|
8.11
|
206.7
|
0.1
|
66.7
|
0.2
|
.358
|
20
|
WST
|
|
STF 2872
|
A BC
|
22086
|
+5917
|
7.14
|
7.98
|
315.0
|
0.1
|
22.8
|
0.2
|
.358
|
20
|
WST
|
Table 2: Residuals from Known Orbits (6th Catalogue)
|
Pair
|
ADS (HIP)
|
Residual (O-C) PA (0)
|
Residual
(O-C) Sep (‘’)
|
Orbit
|
Period (yrs)
|
Date
|
Grade
|
|
STF 1321 AB
|
7251
|
-1.0
|
-0.1
|
Chang
|
975
|
1972
|
4
|
|
STF 2241 AB
|
10759
|
-2.8
|
0.0
|
Kiselev
|
10 000
|
2009
|
5
|
|
STF 2308 AB
|
11061
|
+0.8
|
-0.1
|
Kiselev
|
18 000
|
1996
|
5
|
|
STFA 46 AB
|
12815
|
-1.3
|
-0.3
|
Marcy
|
135127
|
1999
|
4
|
|
STF 2758
|
14638
|
+1.3
|
-0.1
|
Pk
|
678
|
2006
|
4
|
(All Residuals: Observed – latest Catalogue measurement)
Table 3: Residuals from Fourth Catalogue of Interferometric Measurements
|
Pair
|
ADS (BDS)
|
HIP (TYC)
|
Epoch (catalogue)
|
Residual
PA (0)
|
Residual
Sep (‘’)
|
|
|
|
|
|
|
|
|
S 457 AB
|
(2400)
|
22716
|
1991.57
|
-0.7
|
-0.2
|
|
STF 612 AB
|
3514
|
(9165 00808)
|
1991.43
|
-0.4
|
-0.9
|
|
SHJ 49 AB
|
3579
|
23161
|
1991.46
|
+0.6
|
-0.3
|
|
STF 627 AB
|
3597
|
23287
|
2004.116
|
-0.1
|
+0.9
|
|
BVD 50 AB
|
|
23977
|
1991.665
|
+0.2
|
0.0
|
|
|
|
|
|
|
|
|
STF 696 AB
|
3962
|
25142
|
2002.901
|
-0.4
|
+0.4
|
|
STF 697 AB
|
3969
|
25207
|
1991.54
|
+1.3
|
-0.6
|
|
STF 734 AC
|
4150
|
26020
|
2002.901
|
-0.3
|
-0.1
|
|
STF 747 AB
|
4182
|
26199
|
1991.64
|
+0.6
|
+0.1
|
|
STF 855 AB
|
4749
|
29151
|
2002.977
|
+0.9
|
+0.4
|
|
|
|
|
|
|
|
|
STF 1062 AB
|
6012
|
35785
|
2002.996
|
+1.2
|
-0.9
|
|
STF 1315 AB
|
7226
|
45206
|
1991.59
|
+0.9
|
+0.3
|
|
STF 1321 AB
|
7251
|
45343
|
1991.81
|
+7.7
|
-0.8
|
|
Pair
|
ADS (BDS)
|
HIP (TYC)
|
Epoch (catalogue)
|
Residual
PA (0)
|
Residual
Sep (‘’)
|
|
|
|
|
|
|
|
|
STF 1369 AB
|
7438
|
47053
|
2003.311
|
-0.1
|
+0.2
|
|
STF 1415 AB
|
7705
|
50433
|
2003.251
|
+0.7
|
0.0
|
|
|
|
|
|
|
|
|
STF 1603 AB
|
8434
|
59176
|
1991.63
|
+1.6
|
+0.3
|
|
STF 2241 AB
|
10759
|
86614
|
1991.70
|
-1.5
|
-0.6
|
|
STTA 163 AB
|
(8295)
|
87815
|
1991.64
|
+2.6
|
-0.6
|
|
STF 2273 AB
|
10985
|
88071
|
1991.77
|
-0.9
|
+1.3
|
|
STF 2308 AB
|
11061
|
88136
|
2012.7725
|
+2.0
|
-0.8
|
|
|
|
|
|
|
|
|
STF 2278 AB
|
11035
|
88381
|
1991.60
|
+0.9
|
+0.1
|
|
STF 2420 AB
|
11779
|
92512
|
2003.628
|
-3.4
|
+1.1
|
|
SHJ 286 AB
|
12007
|
93717
|
2003.418
|
+1.7
|
+0.4
|
|
STF 2497 AB
|
(9208)
|
95017
|
1991.79
|
-0.6
|
-0.7
|
|
STFA 43 AB
|
12540
|
95947
|
2003.418
|
+0.8
|
+0.8
|
|
|
|
|
|
|
|
|
STF 2549 AD
|
12586
|
96002
|
1991.76
|
-2.4
|
+1.2
|
|
ARN 82 AB
|
(BD+35 3705)
|
(2667 00321)
|
1991.61
|
-1.4
|
+0.6
|
|
STFA 46 AB
|
12815
|
96895
|
2003.628
|
-2.0
|
+0.4
|
|
H 5 137 AB
|
12900
|
97442
|
2003.628
|
0.0
|
+0.6
|
|
STFA 48 AB
|
(9705)
|
97876
|
1991.69
|
+0.2
|
-0.4
|
|
|
|
|
|
|
|
|
STF 2594 AB
|
13087
|
97966
|
2003.418
|
+0.4
|
+0.6
|
|
SHJ 314 AF
|
13374
|
99002
|
2003.695
|
+0.3
|
+1.6
|
|
WEB 12 AB
|
|
(1625 00995)
|
1991.703
|
+0.2
|
-0.9
|
|
S 738 AB
|
13463
|
99409
|
1991.61
|
-0.6
|
+0.7
|
|
S 735 AB
|
(9961)
|
99476
|
1991.49
|
+1.7
|
+1.0
|
|
S 740 AB
|
(10012)
|
99729
|
1991.54
|
+0.4
|
+0.6
|
|
|
|
|
|
|
|
|
STF 2664 AB
|
(BD+12 4291)
|
100226
|
1991.49
|
-0.5
|
-0.5
|
|
STF 2687 AB
|
13870
|
100868
|
2003.629
|
+0.2
|
-0.7
|
|
S 749 AB
|
13868
|
100896
|
1991.46
|
+0.4
|
+0.2
|
|
Pair
|
ADS (BDS)
|
HIP (TYC)
|
Epoch (catalogue)
|
Residual
PA (0)
|
Residual
Sep (‘’)
|
|
STF 2691 AB
|
13919
|
101109
|
1991.68
|
+0.6
|
-0.9
|
|
STF 2690 A BC
|
13946
|
101233
|
1991.52
|
+1.2
|
+1.3
|
|
|
|
|
|
|
|
|
STF 2703 AB
|
(10161)
|
101700
|
1991.64
|
-0.1
|
-0.2
|
|
STF 2758 AB
|
14636
|
104214
|
1991.69
|
+5.8
|
+1.6
|
|
STF 2769 AB
|
14710
|
104539
|
2003.784
|
-0.2
|
+0.9
|
|
STT 447 AE
|
15186
|
(3191 00346)
|
1991.67
|
-1.8
|
+0.2
|
|
S 800 AB
|
15434
|
108073
|
1991.61
|
-0.1
|
+0.2
|
|
|
|
|
|
|
|
|
ARY 45 AB
|
(1225)
|
109275
|
1991.67
|
+0.1
|
+0.1
|
|
STF 2872 A BC
|
15670
|
(3981 01587)
|
1991.68
|
-0.9
|
+1.6
|
Table 4: Alternative Residuals: WDS
|
Pair
|
Epoch: WDS
(Fourth Catalogue)
|
Residual PA (0): WDS (Fourth Catalogue)
|
Residual Sep (“): WDS (Fourth Catalogue)
|
|
STF 1321 AB
|
2018 (1991.81)
|
0.0 (-0.8)
|
-0.3 (+7.7)
|
|
STF 1603 AB
|
2018 (1991.63)
|
-0.5 (+0.3)
|
+0.1 (+1.6)
|
|
STTA 163 AB
|
2017 (1991.64)
|
-0.4 (-0.6)
|
-0.2 (+2.6)
|
|
STF 2308 AB
|
2018 (2012.7725)
|
-0.2 (-0.8)
|
0.0 (+2.0)
|
|
STF 2420 AB
|
2017 (2003.628)
|
-1.0 (+1.1)
|
+0.1 (-3.4)
|
|
|
|
|
|
|
STF 2549 AD
|
2018 (1991.76)
|
-2.0 (+1.2)
|
0.0 (-2.4)
|
|
STFA 46 AB
|
2018 (2003.628)
|
-1.9 (+0.4)
|
-0.4 (-2.0)
|
|
S 735 AB
|
2018 (1991.61)
|
0.0 (+1.0)
|
+0.4 (+1.7)
|
|
STF 2690 A BC
|
2018 (1991.52)
|
+0.4 (+1.3)
|
+0.8 (+1.2)
|
|
STF 2758 AB
|
2018 (1991.69)
|
+0.7 (+1.6)
|
-0.3 (+5.8)
|
|
|
|
|
|
|
STT 447 AE
|
2017 (1991.67)
|
-1.5 (+0.2)
|
+0.2 (-1.8)
|
|
STF 2872 A BC
|
2018 (1991.68)
|
-1.1 (+1.6)
|
+1.1 (-0.9)
|
[/et_pb_text][/et_pb_column][/et_pb_row][/et_pb_section]
mage by Leigh Slomer 26 light frames at 75 seconds ISO 800. 15 darks frames 20 flat frames Equipment used: Canon EOS200D Sigma 30mm f1.4 EX DC HSM lens @ f2.2 Skywatcher Star Adventurer tracking mount. Processed in Deep Sky Stacker and GIMP[/caption][caption id="" align="aligncenter" width="800"]
Image by Leigh Sloamer I made an attempt at capturing the milky way last night. This is a 14 x 3 minute stack at iso 3200. I would have captured more but my new lens is a dew magnet. I also had to crop the image a bit due to amp glow in the lower left corner.[/caption][caption id="" align="aligncenter" width="800"]
Image by John Archer Thought I would pop out and snap the Milky Way while the evening is still mild and the breeze has died down. Bit of a change from planet spotting....[/caption][caption id="" align="aligncenter" width="416"]
Image by Honor Wheeler finally found this image of the Milky Way taken from my back garden on the evening of the 23rd of August 2014. I'd just got back from the cinema and the sky was amazing. As you'll see it was a single shot with my Canon 1100D on a tripod, no tracking! Black and White as light pollution was an issue.[/caption][caption id="" align="aligncenter" width="800"]
Image by Richard Bohner Taken with Canon 6D with wide angle lens at 24 mm at iso 1600 for 60 seconds. Jupiter & Saturn at far left with Sagittarius Teapot to left of galaxy and constellation Scorpius to right of galaxy. Taken on 15 June in Arizona, USA. (Richard lives in the USA so this is a valid entry)[/caption]
Image by Leigh Slomer - no details provided[/caption]
Image by Simon Dawes SkyWatcher, MN190, EQ6, ZWO ASI1600MM[/caption]