Reductions of Crater Timings

The 2000 July 16 Total Lunar Eclipse -

Byron Soulsby

Calwell Lunar Observatory, Australia

Introduction

This was one of the clearest lunar eclipses ever observed, the imaged moon and umbra were distinct and with very good definition in the three video cameras used, although Peter Anderson reported with his crater timings and images that the sky transparency above Brisbane was not good. Robert & Elizabeth Price near Bethanga Victoria reported crater timings and images, and Maurice Clark near Perth WA provided many crater timings as did Stephen and Kathy Kerr with Bill Oliver of the AAQ, and Tony Dutton from Wynnum, Brisbane, QLD.

Crater Timing Analysis

The crater timings received from all observers have been reduced for umbral enlargement and umbral oblateness. The results are shown in the tables below:

UMBRAL ENARGEMENT : STATISTICAL ACCEPTANCE USED IS 0 < %E < 4

Crater TImings

Received

IMMERSIONS

EMERSIONS

OBSERVERS

NUMBER

MEAN %E

M E

NUMBER

MEAN %E

M E

ANDERSON PETER

36

2.2336

0.1535

30

1.8095

0.1433

DUTTON TONY

10

1.9346

0.2251

PRICE ROBERT & ELIZABETH

40

2.1539

0.1382

16

1.8551

0.2586

KERR STEPHEN & KATHY

39

1.7880

0.1237

OLIVER BILL

9

1.8789

0.3357

CLARK MAURICE

99

1.8517

0.0858

129

2.1952

0.0717

Overall Mean %E for 233 IMMERSIONS is 1.9565, +/-0.1272

Overall Mean %E for 175 EMERSIONS is 2.0980, +/-0.1010

Values of F & FM are 298.26, 211.60

Legend: Number of timings which gave rise to a mean percent enlargement (%E) within the statistical acceptance, and ME is the error of the mean from each set of timings.

OBLATENESS ESTIMATES : STATISTICAL RANGE IS 0 % TO 4 %

OBSERVERS

TYPE

No

Ecc

Re

Rp

Fo

SD

SK'

ANDERSON PETER

IM - O

36

0.3583

0.7792

0.7275

15.0581

0.0432

14.0527

EM - O

30

0.1126

0.7282

0.7236

157.2077

0.0175

1.3460

PRICE ROBERT & ELIZABETH

IM - O

40

0.1653

0.7356

0.7255

72.6711

0.0089

2.9118

EM - O

16

0.3153

0.7615

0.7227

19.5992

0.0109

10.7967

KERR STEPHEN & KATHY

IM - O

39

0.2001

0.7376

0.7227

49.4647

0.0079

4.2779

CLARK MAURICE

IM - O

99

0.0887

0.7264

0.7235

253.7308

0.0088

0.8340

EM - O

129

0.1533

0.7351

0.7264

84.6010

0.0190

2.5012

Legend: Type is IM immersion timings, EM is emersion timings with O observed. No is the number of timings, Ecc is the eccentricity of the umbra, Re is the equatorial diameter (in decimal degrees), Rp the polar diameter, Fo the observed reciprocal oblateness of the umbra, SD the deviation of the mean Fo and SK' the ratio compared with the expected reciprocal oblateness FM (211.6) - see Meeus, J.

Discussion

From the analysis of the many crater timings received the enlargement of the umbra was from 1.95 to 2.09 % very near the value expected. The more sensitive analysis of umbral oblateness from most of these crater timings showed a very wide scatter from 14 to 0.8 times the expected value.

Listing

A complete listing of all crater timings reduced can be seen here.