Table 1. Open in new tab Bradley’s...

Date	Time	JD	RA (α_B)	RA (α_E)	α_B − α_E	Dec (δ_B)	Dec (δ_E)	δ_B − δ_E
October 20	20:05	3.33682	308.46252	308.41088	3.098	−13.60611	−13.55332	−3.167	Halley
October 21	18:21	4.26460	307.11111	307.09433	1.007	−11.13750	−11.13303	−0.268	Bradley
October 23	19:22	6.30696	305.11221	305.09902	0.792	−7.31778	−7.31362	−0.249	Bradley
	20:50	6.36807	305.06000	305.05268	0.439	−7.22222	−7.22236	0.008	Bradley
October 24	18:58	7.29029	304.37778	304.42153	−2.625	−6.16667	−5.96508	−12.095	Bradley
October 25	20:57	8.37293	303.81944	303.81609	0.201	−4.73167	−4.72849	−0.191	Bradley
October 26	18:35	9.27432	303.41111	303.39876	0.741	−3.85083	−3.85296	0.128	Bradley
November 01	18:22	15.26529	301.80639	301.79725	0.548	−0.10000	−0.10177	0.106	Bradley
November 02	18:24	16.26668	301.65472	301.65197	0.165	+0.31667	0.31418	0.149	Bradley
November 04	20:02	18.33473	301.42611	301.41950	0.397	+1.06944	1.06209	0.441	Bradley
November 09	20:56	23.37223	301.12222	301.12900	−0.407	+2.45556	2.45207	0.209	Bradley
November 10	18:20	24.26390	301.10556	301.10792	−0.142	+2.65750	2.65354	0.238	Bradley
November 16	17:53	30.24515	301.13333	301.13217	0.070	+3.79389	3.78930	0.275	Bradley
November 19	19:06	33.29585	301.23056	301.23194	−0.083	+4.26028	4.26764	−0.442	Bradley
November 25	18:20	39.26390	301.54583	301.55213	−0.378	+5.09167	5.08888	0.167	Bradley
December 01	19:45	45.32293	301.99722	302.00681	−0.575	+5.81528	5.83260	−1.039	Halley
December 18	18:45	62.28126	303.70972	303.70706	0.160	+7.77500	7.77310	0.114	Bradley
				\|$\langle {\Delta \alpha }\rangle = {0.20\prime }$\|	\|$\langle {\Delta \delta }\rangle = -{0.02\prime }$\|
				\|$S_{\Delta \alpha }={0.47\prime }$\|	\|$S_{\Delta \delta }={0.37\prime }$\|

Date

Time

RA (α_B)

RA (α_E)

α_B − α_E

Dec (δ_B)

Dec (δ_E)

δ_B − δ_E

(month dd)

(hh:mm)

−2350662

(°)

(′)

(°)

(′)

Observer

October 20

20:05

3.33682

308.46252

308.41088

3.098

−13.60611

−13.55332

−3.167

Halley

October 21

18:21

4.26460

307.11111

307.09433

1.007

−11.13750

−11.13303

−0.268

Bradley

October 23

19:22

6.30696

305.11221

305.09902

0.792

−7.31778

−7.31362

−0.249

Bradley

20:50

6.36807

305.06000

305.05268

0.439

−7.22222

−7.22236

0.008

Bradley

October 24

18:58

7.29029

304.37778

304.42153

−2.625

−6.16667

−5.96508

−12.095

Bradley

October 25

20:57

8.37293

303.81944

303.81609

0.201

−4.73167

−4.72849

−0.191

Bradley

October 26

18:35

9.27432

303.41111

303.39876

0.741

−3.85083

−3.85296

0.128

Bradley

November 01

18:22

15.26529

301.80639

301.79725

0.548

−0.10000

−0.10177

0.106

Bradley

November 02

18:24

16.26668

301.65472

301.65197

0.165

+0.31667

0.31418

0.149

Bradley

November 04

20:02

18.33473

301.42611

301.41950

0.397

+1.06944

1.06209

0.441

Bradley

November 09

20:56

23.37223

301.12222

301.12900

−0.407

+2.45556

2.45207

0.209

Bradley

November 10

18:20

24.26390

301.10556

301.10792

−0.142

+2.65750

2.65354

0.238

Bradley

November 16

17:53

30.24515

301.13333

301.13217

0.070

+3.79389

3.78930

0.275

Bradley

November 19

19:06

33.29585

301.23056

301.23194

−0.083

+4.26028

4.26764

−0.442

Bradley

November 25

18:20

39.26390

301.54583

301.55213

−0.378

+5.09167

5.08888

0.167

Bradley

December 01

19:45

45.32293

301.99722

302.00681

−0.575

+5.81528

5.83260

−1.039

Halley

December 18

18:45

62.28126

303.70972

303.70706

0.160

+7.77500

7.77310

0.114

Bradley

|$\langle {\Delta \alpha }\rangle = {0.20\prime }$|

|$\langle {\Delta \delta }\rangle = -{0.02\prime }$|

|$S_{\Delta \alpha }={0.47\prime }$|

|$S_{\Delta \delta }={0.37\prime }$|

Date	Time	JD	RA (α_B)	RA (α_E)	α_B − α_E	Dec (δ_B)	Dec (δ_E)	δ_B − δ_E
October 20	20:05	3.33682	308.46252	308.41088	3.098	−13.60611	−13.55332	−3.167	Halley
October 21	18:21	4.26460	307.11111	307.09433	1.007	−11.13750	−11.13303	−0.268	Bradley
October 23	19:22	6.30696	305.11221	305.09902	0.792	−7.31778	−7.31362	−0.249	Bradley
	20:50	6.36807	305.06000	305.05268	0.439	−7.22222	−7.22236	0.008	Bradley
October 24	18:58	7.29029	304.37778	304.42153	−2.625	−6.16667	−5.96508	−12.095	Bradley
October 25	20:57	8.37293	303.81944	303.81609	0.201	−4.73167	−4.72849	−0.191	Bradley
October 26	18:35	9.27432	303.41111	303.39876	0.741	−3.85083	−3.85296	0.128	Bradley
November 01	18:22	15.26529	301.80639	301.79725	0.548	−0.10000	−0.10177	0.106	Bradley
November 02	18:24	16.26668	301.65472	301.65197	0.165	+0.31667	0.31418	0.149	Bradley
November 04	20:02	18.33473	301.42611	301.41950	0.397	+1.06944	1.06209	0.441	Bradley
November 09	20:56	23.37223	301.12222	301.12900	−0.407	+2.45556	2.45207	0.209	Bradley
November 10	18:20	24.26390	301.10556	301.10792	−0.142	+2.65750	2.65354	0.238	Bradley
November 16	17:53	30.24515	301.13333	301.13217	0.070	+3.79389	3.78930	0.275	Bradley
November 19	19:06	33.29585	301.23056	301.23194	−0.083	+4.26028	4.26764	−0.442	Bradley
November 25	18:20	39.26390	301.54583	301.55213	−0.378	+5.09167	5.08888	0.167	Bradley
December 01	19:45	45.32293	301.99722	302.00681	−0.575	+5.81528	5.83260	−1.039	Halley
December 18	18:45	62.28126	303.70972	303.70706	0.160	+7.77500	7.77310	0.114	Bradley
				\|$\langle {\Delta \alpha }\rangle = {0.20\prime }$\|	\|$\langle {\Delta \delta }\rangle = -{0.02\prime }$\|
				\|$S_{\Delta \alpha }={0.47\prime }$\|	\|$S_{\Delta \delta }={0.37\prime }$\|

Table 1.

Open in new tab

Bradley’s observations of C/1723 T1.*

Date	Time	JD	RA (α_B)	RA (α_E)	α_B − α_E	Dec (δ_B)	Dec (δ_E)	δ_B − δ_E
(month dd)	(hh:mm)	−2350662	(°)	(°)	(′)	(°)	(°)	(′)	Observer
October 20	20:05	3.33682	308.46252	308.41088	3.098	−13.60611	−13.55332	−3.167	Halley
October 21	18:21	4.26460	307.11111	307.09433	1.007	−11.13750	−11.13303	−0.268	Bradley
October 23	19:22	6.30696	305.11221	305.09902	0.792	−7.31778	−7.31362	−0.249	Bradley
	20:50	6.36807	305.06000	305.05268	0.439	−7.22222	−7.22236	0.008	Bradley
October 24	18:58	7.29029	304.37778	304.42153	−2.625	−6.16667	−5.96508	−12.095	Bradley
October 25	20:57	8.37293	303.81944	303.81609	0.201	−4.73167	−4.72849	−0.191	Bradley
October 26	18:35	9.27432	303.41111	303.39876	0.741	−3.85083	−3.85296	0.128	Bradley
November 01	18:22	15.26529	301.80639	301.79725	0.548	−0.10000	−0.10177	0.106	Bradley
November 02	18:24	16.26668	301.65472	301.65197	0.165	+0.31667	0.31418	0.149	Bradley
November 04	20:02	18.33473	301.42611	301.41950	0.397	+1.06944	1.06209	0.441	Bradley
November 09	20:56	23.37223	301.12222	301.12900	−0.407	+2.45556	2.45207	0.209	Bradley
November 10	18:20	24.26390	301.10556	301.10792	−0.142	+2.65750	2.65354	0.238	Bradley
November 16	17:53	30.24515	301.13333	301.13217	0.070	+3.79389	3.78930	0.275	Bradley
November 19	19:06	33.29585	301.23056	301.23194	−0.083	+4.26028	4.26764	−0.442	Bradley
November 25	18:20	39.26390	301.54583	301.55213	−0.378	+5.09167	5.08888	0.167	Bradley
December 01	19:45	45.32293	301.99722	302.00681	−0.575	+5.81528	5.83260	−1.039	Halley
December 18	18:45	62.28126	303.70972	303.70706	0.160	+7.77500	7.77310	0.114	Bradley
				\|$\langle {\Delta \alpha }\rangle = {0.20\prime }$\|			\|$\langle {\Delta \delta }\rangle = -{0.02\prime }$\|
				\|$S_{\Delta \alpha }={0.47\prime }$\|			\|$S_{\Delta \delta }={0.37\prime }$\|

Date	Time	JD	RA (α_B)	RA (α_E)	α_B − α_E	Dec (δ_B)	Dec (δ_E)	δ_B − δ_E
(month dd)	(hh:mm)	−2350662	(°)	(°)	(′)	(°)	(°)	(′)	Observer
October 20	20:05	3.33682	308.46252	308.41088	3.098	−13.60611	−13.55332	−3.167	Halley
October 21	18:21	4.26460	307.11111	307.09433	1.007	−11.13750	−11.13303	−0.268	Bradley
October 23	19:22	6.30696	305.11221	305.09902	0.792	−7.31778	−7.31362	−0.249	Bradley
	20:50	6.36807	305.06000	305.05268	0.439	−7.22222	−7.22236	0.008	Bradley
October 24	18:58	7.29029	304.37778	304.42153	−2.625	−6.16667	−5.96508	−12.095	Bradley
October 25	20:57	8.37293	303.81944	303.81609	0.201	−4.73167	−4.72849	−0.191	Bradley
October 26	18:35	9.27432	303.41111	303.39876	0.741	−3.85083	−3.85296	0.128	Bradley
November 01	18:22	15.26529	301.80639	301.79725	0.548	−0.10000	−0.10177	0.106	Bradley
November 02	18:24	16.26668	301.65472	301.65197	0.165	+0.31667	0.31418	0.149	Bradley
November 04	20:02	18.33473	301.42611	301.41950	0.397	+1.06944	1.06209	0.441	Bradley
November 09	20:56	23.37223	301.12222	301.12900	−0.407	+2.45556	2.45207	0.209	Bradley
November 10	18:20	24.26390	301.10556	301.10792	−0.142	+2.65750	2.65354	0.238	Bradley
November 16	17:53	30.24515	301.13333	301.13217	0.070	+3.79389	3.78930	0.275	Bradley
November 19	19:06	33.29585	301.23056	301.23194	−0.083	+4.26028	4.26764	−0.442	Bradley
November 25	18:20	39.26390	301.54583	301.55213	−0.378	+5.09167	5.08888	0.167	Bradley
December 01	19:45	45.32293	301.99722	302.00681	−0.575	+5.81528	5.83260	−1.039	Halley
December 18	18:45	62.28126	303.70972	303.70706	0.160	+7.77500	7.77310	0.114	Bradley
				\|$\langle {\Delta \alpha }\rangle = {0.20\prime }$\|			\|$\langle {\Delta \delta }\rangle = -{0.02\prime }$\|
				\|$S_{\Delta \alpha }={0.47\prime }$\|			\|$S_{\Delta \delta }={0.37\prime }$\|

Bradley observed the comet at Wanstead in Essex, after he was alerted by Edmond Halley to the appearance of the comet. He used a telescope with a focal length of seven feet, equipped with a micrometer, which results in a sub-arcminute precision.

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