CALWELL LUNAR OBSERVATORY

(Longitude 149o06'00.9" E, Latitude -35o26'31.4" S, Elevation 630 m)

 

Byron W. Soulsby, 23 Andrew Crescent, Calwell, A C T, 2905 AUSTRALIA

Telephone: (06) 2926591, Computer Fax: (06) 2928247, e-mail: minnah@netspeed.com.au

World Wide Web Internet HOME PAGE: http://www.netspeed.com.au/minnah/LEOx.html

Illustrated above is my first CCD image analysed from the eclipse of 1990 February 9.

 

Amended 1996 September 17

 

ANALYSIS OF OBSERVATIONS OF THE 1996 APRIL 3-4 TOTAL LUNAR ECLIPSE

 

Introduction

For the first time details of how to observe the total lunar eclipse of 1996 April 3-4 were announced on the Internet in my new World Wide Web page at URL:

 

http://www.netspeed.com.au/minnah/LEO.html

 

This resulted in some unique e-mail responses, such as the query from the Maryland Virtual High School on their experiments to measure the distance to the Moon during this eclipse including a comparison with one of my measured eclipse video images included on the home page; the date of the lunar eclipse for the first day Jewish festival Passover; the visibility and colours of the eclipse as observed in Ireland; and an interesting summary of past partial lunar eclipses each with a magnitude of just below 1.0, which will be the case for the 1997 March 24 eclipse also included on my home page. Long time lunar eclipse observer Tim Cooper reported by e-mail from Johannesburg, South Africa, that he was rained out during the eclipse.

In addition, other astronomers contributed crater timings of this eclipse both by mail and e-mail. The analysis of the crater timings received are given for the increase in the size of the umbra (%E), and estimates of the reciprocal umbral oblateness (Fo), with lists of crater timing reductions for each observer.

 

Crater Timings

The times where the Earth's shadow, or umbra contacts the rim and centre of lunar features during a lunar eclipse yields important data concerning the geometry of the umbra, such as the percent enlargement (%E) of the shadow due to atmospheric refraction, and observed oblateness, due to the greater ellipticity of the atmosphere, when compared to the solid Earth, or its Geoid.

Twenty four astronomers, five from The Netherlands, one from Spain and eighteen from Brasil, have submitted their crater timings for analysis. Their 636 observations are given in tabulated summaries of umbral enlargement and reciprocal umbral oblateness estimates. The derived summarised data are presented in twoof the tables following. NOTE: A description of the nomenclature used in the tables is given in the two World Wide Web Internet References.

The individual observers' crater timing reductions are given in the 24 tables available at the link: * Analysis of Individual observations of the 1996 April 3-4 total lunar eclipse.

 

Comments

There was some variation in %E, with 2.238 % from 333 crater immersions and 2.293 % from 303 emersions, but the values derived were in the main greater than the expected 2%.

 

The non-statistical immersion umbral oblateness values from the observer's data were 8.6, 2.5, 9.1, 8.2, 3.8, 5.7, 2.8 and 9 times greater than the expected geometric value (Fm) derived from Meeus. There were also non-statistical oblateness estimates from the emersion timing data sets of 2.3, 2.3, 4.3, 1.3, 2.0, 1.4 and 4 times greater than Fm.

It was expected that the primary contact observations where the Moon enters and exits the umbra would show later immersion and earlier emersion times due to the oblate geometry of the umbra. A comparison of the primary contact observations found that no definitive trend occured, except for first contact where 5/9 of the timings were late and for third contact, where 8/11 of the observed times were earlier than that predicted from the Geoid oblateness.

 

Analysis of video records

Three observers have provided video records of this eclipse for analysis. This work is presented in a separate report through the link: * Analysis of video observations of the 1996 April 3-4 total lunar eclipse.

 

Conclusions

The crater timings from João Batista França Nunes, produced a statistical reciprocal oblateness (Fo) of 62 as shown in the linear-best-fit plot of Figure 1. Other observers that gave similar results when their timings were analysed in a similar manner, were Ribeira with Fo = 76, Coelho Fo = 83 and Trevisan Fo = 142. The average statistical value of umbral oblateness from these 5 observers was 1/103.4, which is very near the mean value of 1/102 established from previous analyses of the Soulsby Series which now embraces 28 lunar eclipses.

 

References

 

1. http://www.netspeed.com.au/minnah/LEO.html

2. http://www.netspeed.com.au/minnah/EclipseAnalysis.html

 

 

 

ANALYSIS OF LUNAR ECLIPSE OBSERVATIONS

BY BYRON W. SOULSBY, CALWELL LUNAR OBSERVATORY, AUSTRALIA

**** %E SUMMARY ****

STATISTICAL ACCEPTANCE USED IS 0 < %E < 4

CRATER TIMING REDUCTIONS FOR 1996 APRIL 3-4

 

IMMERSIONS EMERSIONS

OBSERVER

NUMBER

MEAN %E

MEAN ERROR

NUMBER

MEAN %E

MEAN ERROR

BULDER, HENK J. J.

41

1.9671

0.0747

2

2.3717

0.1094

GERRITSEN, ADRI A.

33

2.3498

0.0562

35

1.8878

0.0689

BIKKER, I.B.A.

6

2.1889

0.0907

7

2.3965

0.2368

VITAL, HELIO DE C.

23

2.1077

0.0933

23

2.3029

0.1074

COELHO, ANTONIO C. A.

6

2.7398

0.1834

18

2.6203

0.1351

FILHO, ANTONIO P.

16

2.0689

0.1264

18

2.3392

0.0987

GERRUDA, F. S. B.

2

3.4229

0.2840

5

2.3775

0.1673

BARRETO, MARCOS J. R.

2

3.4840

0.2261

1

3.1246

0.0000

NUNES, JOAO B. F.

36

2.7134

0.0721

32

2.2993

0.1194

VARGAS, LUCIMARY

49

2.0169

0.0756

49

2.3862

0.0768

JUNIOR, ANTONIOC.G.

24

2.2306

0.0965

22

2.3296

0.1052

FUNARI, FREDERICA

8

2.5083

0.1079

9

2.0709

0.1017

TREVISA, NEDVALDAJ.

9

2.2231

0.0747

11

2.0463

0.0462

CARBONI, CLAUDIO

3

2.7500

0.0899

4

2.7440

0.2093

SANTOS, JOAO R.

9

1.8640

0.1184

11

2.7970

0.1536

RIBEIRA, ANGELO C.

19

2.4953

0.1541

24

1.9601

0.0764

BLOMMERS, LEX

6

2.1249

0.1150

5

3.0724

0.1951

SCHOLTEN, ALEX H.

6

1.2509

0.1163

-



LARA, MARCOS

2

1.4437

0.9522

2

2.4046

0.1968

JOEL, FURLANI

5

2.2848

0.2083

4

2.2198

0.2825

LUIZ, F. ZIBORDI

9

2.0079

0.1571

10

2.4231

0.2235

BARRETO, MARCOS J. R.

2

1.4437

0.9522

2

2.4046

0.1968

MARILENA, MOLLACO

2

2.0639

0.0677

2

1.8860

0.0181

CASTANO, JOSE GOMEZ

15

2.3907

0.1986

8

2.2489

0.1993

 

OVERALL MEAN %E FOR 333 IMMERSIONS IS 2.2382 +/-0.1066 %

 

OVERALL MEAN %E FOR 303 EMERSIONS IS 2.2927 +/-0.1130 %

VALUES OF F & FM ARE 298.26, 214.825

DATE: 16-09-1996 AT TIME 16:03:14

 

ANALYSIS OF LUNAR ECLIPSE OBSERVATIONS

BY BYRON W. SOULSBY, CALWELL LUNAR OBSERVATORY, AUSTRALIA

**** OBLATENESS FROM CRATER TIMINGS ****

DERIVED FROM CRATER TIMING REDUCTIONS FOR 1996 APRIL 3-4

 

STATISTICAL RANGE IS 0 < %E < 4 %

TYPE

Obs. or

No

Ecc

Re

Rp

Fo

SD

SK'

Theory








OBSERVER HENK J. J. BULDER









IM

O

41

0.2800

0.7662

0.7355

25.0051

0.0352

8.5913

IM

T

41

0.0318

0.7209

0.7206

-

0.0005

0.1089

OBSERVER ADRI A. GERRITSEN









IM

O

33

0.1528

0.7464

0.7376

85.1749

0.0182

2.5222

IM

T

33

0.0624

0.7219

0.7205

-

0.0072

0.4182

EM

O

35

0.0217

0.7343

0.7341

-

0.0091

0.0506

EM

T

35

0.1067

0.7260

0.7219

175.1659

0.0475

1.2264

OBSERVER: LUCIMARY VARGAS









IM

O

49

0.0616

0.7365

0.7351

-

0.0056

0.4075

IM

T

49

0.0427

0.7212

0.7206

-

0.0058

0.1959

EM

O

49

0.1462

0.7484

0.7403

93.1285

0.0623

2.3068

EM

T

49

0.1018

0.7257

0.7219

192.5234

0.0416

1.1158

OBSERVER: HELIO DE CARVALHO VITAL









IM

O

23

0.2885

0.7692

0.7365

23.5210

0.0341

9.1333

IM

T

23

0.0478

0.7214

0.7206

-

0.0005

0.2454

EM

O

23

0.1471

0.7480

0.7399

91.9230

0.0665

2.3370

EM

T

23

0.0970

0.7252

0.7218

211.9212

0.0421

1.0137

OBSERVER: ANTONIO CARLOS ALBUQUERQUE COELHO









IM

O

6

0.2745

0.7696

0.7400

26.0412

0.0052

8.2494

IM

T

6

0.1554

0.7296

0.7208

82.2794

0.0004

2.6109

EM

O

18

0.1990

0.7593

0.7441

49.9867

0.0896

4.2976

EM

T

18

0.0916

0.7247

0.7217

237.7665

0.0393

0.9035

OBSERVER: ANTONIO PADILLA FILHO









IM

O

16

0.1893

0.7493

0.7357

55.3140

0.0220

3.8837

IM

T

16

0.0628

0.7220

0.7206

-

0.0072

0.4240

EM

O

18

0.1082

0.7433

0.7390

170.2623

0.0481

1.2617

EM

T

18

0.0929

0.7249

0.7217

231.2801

0.0396

0.9289

OBSERVER: ANTONIO C. G. JUNIOR









IM

O

24

0.2292

0.7564

0.7362

37.5585

0.0051

5.7197

IM

T

24

0.0306

0.7209

0.7206

-

0.0036

0.1009

EM

O

22

0.1358

0.7466

0.7397

107.9135

0.0608

1.9907

EM

T

22

0.0962

0.7252

0.7218

215.4484

0.0413

0.9971

OBSERVER: ANGELO C. RIBEIRA









IM

O

19

0.1601

0.7480

0.7384

77.5596

0.0075

2.7698

IM

T

19

0.0684

0.7222

0.7205

426.5152

0.0005

0.5037

EM

O

24

0.1140

0.7412

0.7364

153.4784

0.0505

1.3997

EM

T

24

0.0994

0.7255

0.7219

201.7626

0.0425

1.0647

OBSERVER: JOAO B. F. NUNES









IM

O

36

0.2866

0.7734

0.7410

23.8328

0.0378

9.0138

IM

T

36

0.0203

0.7207

0.7206

-

0.0005

0.0441

EM

O

32

0.1935

0.7561

0.7418

52.9210

0.0875

4.0594

EM

T

32

0.0996

0.7255

0.7219

201.0422

0.0433

1.0686

VALUE OF FM (RECIPROCAL) = 214.82

 

 

In the tables above:

TYPE is IM = Immersions, or EM = Emersions, No = Number of timings,

Ecc = Eccentricity of umbra, Re = Radius at umbral equator, Rp = Radius at umbral pole,

Fo = reciprocal oblateness, SD = standard deviation of data,

SK' = ratio when compared to the expected oblateness (Fm) due to Meeus.

 

 

 

Figure 1: Statistical oblateness from observer: JOAO B. F. NUNES

 

ANALYSIS OF LUNAR ECLIPSE OBSERVATIONS

BY BYRON W. SOULSBY, CALWELL LUNAR OBSERVATORY, AUSTRALIA

**** PRIMARY CONTACTS SUMMARY ****

FOR 1996 APRIL 3-4

 

Times are Universal Time in hours.minutes seconds

 

IMMERSIONS (H.ms) EMERSIONS(H.ms)

 

Observer

 

First contact

Second contact

Third contact

Fourth contact

Comments

Predictions

22.2101

23.2636

00.5250

01.5825

Using F =298.26

22.2103 L

23.2645 L

00.5245 E

01.5817 E

Using F =102

Bulder Henk J. J.

22.2252 L

23.2721 L

-

01.5854 L

All later

Vargas Lucimary

22.2103 L

23.2640 L

00.5227 E

01.5918 L

Three later

Vital Helio De C

22.2114 L

23.2644 L

00.5259 L

01.5845 L

All later

Coelho A. C. A.

-

23.2616 E

00.5235 E

01.5847 L

Two earlier

Filho Antonio P.

22.2206 L

-

00.5316 L

-

All later

Junior A. C. G.

22.2131 L

23.2502 E

00.5242 E

01.5815 E

Three earlier

Funari Frederica

22.2034 E

23.2626 E

00.5218 E

01.5821 E

All earlier

Trevisan E. J.

22.2052 E

23.2624 E

00.5241 E

01.5840 L

Three earlier

Santos Joao R.

-

23.2654 L

00.5218 E

01.5912 L

Two later

Ribeira Angelo C.

22.1912 E

23.2545 E

00.5234 E

01.5814 E

All earlier

Nunes Joao B. F.

-

23.2605 E

00.5138 E

01.5855 L

Two earlier

Castano Jose Gomez

22.2018 E

23.2700 L

00.5311 L

-

Two later

Number

9

11

11

10


Result

5/9 L

5/11 L

8/11 E

3/10 E


E = earlier than the predicted time, L = later than the predicted time of contact.

 

World Wide Web and e-mail Links

Link to Lunar Eclipse Observer Finder Page: Lunar Eclipse Observer Finder Page:

To send e-mail to the author: minnah@netspeed.com.au