2001 January 9 Lunar Eclipse Results:

Reports were received from 19 observers (many having already contributed data for previous eclipses, thus improving consistent comparisons between events). Among observers who had data points sufficiently close in time to mid-eclipse, I selected 11 magnitude values. Giving equal weight to each individual's mid-eclipse mag, yields an average mag -1.8, with standard error 0.13 mag (the 11 individual data points being distributed with 0.4 mag standard deviation, which is typical of the scatter present in data from recent eclipses). To produce the above graph, systematic differences from observer to observer were removed by best-fitting individual data to the -1.8 mag average near mid-eclipse.

The predicted mag from Anthony Mallama's photometric model, was -2.0 +-0.5; thus Observed minus Predicted was +0.2 mag. In previous eclipses since 1996, visual observations systematically tended to be about 0.8 mag brighter than the model predictions, but it is the variations in Observed minus Predicted mag that are of interest for monitoring absorption by volcanic aerosols in the Earth's atmosphere. Like this January, the 1997 Sep eclipse was nearly on top of prediction. This might indicate some marginal aerosol induced dimming, perhaps just above the "noise" level (due to scatter in the data, as well as the stated +-0.5 mag uncertainty of Mallama's model).

The group of observers for which data is available is obviously quite different from eclipse to eclipse, but looking into the individual data by observers who performed estimates at both this and other eclipses in the last 5 years, one can make a more consistent comparison. In particular, there are 4 observers who have data for both this eclipse, and the 1997 Sep eclipse. An average of the magnitude differences M2001-M1997, yields -0.05 +-0.25; i.e. virtually no difference in Observed mag, while the Predicted mag was also identical for both 1997 Sep and 2001 Jan eclipses. Even if one considers that 3 of the 4 observers have M2001-M1997 between -0.2 and -0.4, this is still within the 0.4-0.5 mag uncertainty of both the prediction model, and the observational data. That the recent 2001 Jan eclipse was slightly fainter than expected, is also suggested by the extensive data by one observer obtained at the 2000 Jan and 2001 Jan eclipses. While the predicted brightness of the 2001 Jan eclipse was one mag brighter than the 2000 Jan eclipse, B. H. Granslo's data suggests this year's eclipse was only -0.2 mag brighter.

These individual comparisons, support the above conclusion, that the 1997 Sep and 2001 Jan eclipses were slightly dimmer when compared to model predictions (not in absolute terms of course) than other eclipses since 1996. Both had observed magnitudes on top of predictions, while all other eclipses since 1996 Apr, were on average some 0.8 mag brighter than prediction. This might indicate some marginal aerosol induced dimming was present at both the 1997 Sep and 2001 Jan events.

I would like to thank the following observers for their fine and prompt reports: Nada Abanda (Jordania); Sana'a Abdo (Jordania); Waleed Abu Alia (Jordania); Hani Al-Dalee' (Jordania); Emad Al-Ashi (Jordania); Khalid Al-Tell (Jordania); Jure Atanackov (Zaplana, Slovenia); R. J. Bouma (Groningen, The Netherlands); Bjorn H. Granslo (Tryvann, Oslo, Norway); Gunnar Glitscher (Darmstadt, Germany); Kamil Hornoch (Lelekovice, Czech Republic); Javor Kac (Zaplana, Slovenia); Timo Karhula (Lycksta, Västerås, Sweden); Ahmad Niamat (Jordania); Moh'd Odeh (Jordania); Andrew Pearce (Nedlands, Western Australia); Ja'afar Radaydah (Jordania); Ala' Shahin (Dubai, United Arab Emirates) and Oddleiv Skilbrei (Honefoss, Norway).

Alfredo Pereira, 2001 Jan 22

Mohammad Odeh, again enthusiastically led a very successful observing campaign in his country. The Jordanian Astronomical Society (JAS) organized a public session with over 120 persons attending to observe the total lunar eclipse at Haya Cultural Center (Lon 35 d 54' E; Lat 31 d 58' N; Elevation 920 m). You can check an account at JAS web site: http://www.jas.org.jo/lun01.html.

Time is in UT. Magnitudes are not reduced. Theoretically, reversed 7x50B mags should be reduced by ~ 4.3 mag. and reversed 10x50B mags by ~ 5.0 mag. Adopting these values, the reduced lunar magnitude at mid eclipse is: Odeh (-1.8), Dalee' (-1.7), Abu Alia (-1.4), and Abanda (-1.3).

Observer: Sana' Abdo, using reversed 12x50 B. 

     19:50, 2.7, Theta Aur. 
     20:00, 3.3, Eta Aur. 
     20:10, 3.5, Delta Gem. 
     20:20, 3.8, Lambda Gem + Nu Gem. 
     20:30, 3.5, Delta Gem. 
     20:40, 3.4, Delta Gem + Eta Aur. 
     20:50, 3.0, Theta Aur + Eta Aur. 

Observer: Mohammad Odeh, using reversed 7x50 B.

     20:20, 2.5, Theta Aur. + Beta Aur. 
     20:30, 2.1, Beta Aur. 
     20:40, 1.6, Alpha Gem. 
     20:50, 1.0, Regulus + Alpha CMi 

Observer: Hani Al-Dalee', using reversed 10x50 B.

     19:50, 1.9, Gamma Gem. 
     20:00, 3.3, Eta Aur. 
     20:10, 3.5, Delta Gem. 
     20:20, 3.3, Eta Aur. 
     20:30, 3.1, Eta Aur. + Theta Aur. 
     20:40, 2.9, Eta Aur. + Theta Aur. 
     20:50, 2.7, Theta Aur. 

Observer: Khalid Al-Tell, using reversed 7x35 B.

     19:50, 2.1, Beta Aur. 
     20:00, 2.5, Theta Aur. + Beta Aur. 
     20:10, 2.7, Theta Aur. 
     20:20, 2.5, Theta Aur. + Beta Aur. 
     20:30, 2.5, Theta Aur. + Beta Aur. 
     20:40, 1.7, Alpha Gem. + Gamma Gem 
     20:50, 1.2, Alpha Gem. + Alpha CMi 

Observer: Nada Abanda, using reversed 7x50 B.

     19:50, 1.9, Gamma Gem. 
     20:00, 2.3, Theta Aur. + Beta Aur. 
     20:10, 2.7, Theta Aur. 
     20:20, 3.0, Theta Aur. + Eta Aur. 

Observer: Emad Al-Ashi, using reversed 10x50 B.

     19:50, 1.6, Alpha Gem. 
     20:00, 3.5, Delta Gem. 
     20:10, 1.6, Alpha Gem. (7X50 B) 
     20:20, ---, ------- 
     20:30, 4.0, Nu Gem. 
     20:40, 3.5, Delta Gem. 
     20:50, 2.8, Theta Aur. + Eta Aur. 

Observer: Ahmad Al-Niamat, using reversed 10x50 B.

     19:50, 1.9, Gamma Gem. 
     20:00, 2.7, Theta Aur. 
     20:10, 3.6, Lambda Aur. 
     20:20, Too faint to be seen! 
     20:30, Too faint to be seen! 
     20:40, 2.7, Theta Aur. 
     20:50, 1.9, Gamma Gem. 

Observer: Waleed Abu Alia, using reversed 10x50 B.

     19:50, 1.9, Alpha Gem. 
     20:00, 3.5, Delta Gem. 
     20:10, 3.6, Lambda Gem. 
     20:20, 3.6, Lambda Gem. 
     20:30, 3.3, Eta Aur. 
     20:40, ---, ------ 
     20:50, 2.7, Theta Aur.

R. J. Bouma, Groningen, The Netherlands, used reversed 7x50 binoculars to estimate the Lunar magnitude as follows [comparison stars were alfa (+1.2), gamma (+2.0) and epsilon Gem (+3.0), correction used for the reversed 7x50B was -4.2 mag]:

2001 (UT)   mag
Jan. 9.858  -1.8
Jan. 9.860  -1.9
Jan. 9.863  -2.2
Jan. 9.868  -3.0
Bouma, comments that "around mid eclipse the moon still looked fairly bright, with a near white northern edge, and a pale coppery orange for the rest. It was evident that this was not a central eclipse...".

Bjorn H. Granslo, Tryvann, Oslo, Norway, writes: "This eclipse was successfully observed from near Tryvann, Oslo, Norway (59o59' N, 10o45' E, elevation 520 meters). The sky was mostly clear except during the first penumbral phase. It was rather cold, however, the temperature was about -10 degrees C.

My main observing project was to determine the magnitude of the eclipsed Moon. The motivation for this is that the Moon's total magnitude during an eclipse is strongly dependent of the amount of volcanic and other aerosols in our atmosphere. I estimated the Moon's brightness was during totality and for a period before and after the total phase. Here are my results:

 U.T.     Estimates   Obs. mag.  Instrument  Lunar mag.  deltaT
 h  m                                                       m
19 34     S+4; A+4       -0.4    L24x70R       -7.6      -46.5
19 36.5   S-1; A=M       +0.1    L24x70R       -7.1      -44
19 39     S-5; A+4       +0.5    L24x70R       -6.7      -41.5
19 40.5   S-6; C+4       +0.7    L24x70R       -6.5      -40
19 40.5   J(2)M(8)S      -2.1    B7x50R        -6.6      -40
19 42.5   J(5)M(5)S      -1.3    B7x50R        -5.8      -38
19 43.5   J(8)M(2)S      -0.5    B7x50R        -5.0      -37
19 44     D=M            +1.6    L24x70R       -5.6      -36.5
19 46     S+1; A+1       -0.1    B7x50R        -4.6      -34.5
19 47     G+1; H+3       +2.7    L24x70R       -4.5      -33.5
19 49     A-6; C+4       +0.7    B7x50R        -3.8      -31.5
19 52.5   C=M; D+4       +1.2    B7x50R        -3.3      -28
19 57     C-2; D+2       +1.4    B7x50R        -3.1      -23.5
20 06     D-1; E+2       +1.7    B7x35R        -2.8      -14.5
20 13     D-3; E=M       +1.9    B7x35R        -2.6       -7.5
20 21     E-1; F+3       +2.0    B7x50R        -2.5       +0.5
20 29     D-4; E-1; F+2  +2.0    B7x50R        -2.5       +8.5
20 36     D-2; E+2       +1.8    B7x50R        -2.7      +15.5
20 43     C-3; D+1       +1.5    B7x50R        -3.0      +22.5
20 47     C-1; D+3       +1.3    B7x50R        -3.2      +26.5
20 50     B-7; C+1       +1.1    B7x50R        -3.4      +29.5
20 52.5   B-6; C+2       +1.0    B7x50R        -3.5      +32
20 54     A-2; B=M       +0.3    B7x50R        -4.2      +33.5
20 55     A=M; B+3       +0.1    B7x50R        -4.4      +34.5
20 56     S+2; A+3       -0.2    B7x50R        -4.7      +35.5
20 57     J(7)M(3)S      -0.8    B7x50R        -5.3      +36.5
20 58     J(6)M(4)S      -1.0    B7x50R        -5.5      +37.5
20 59     J(5)M(5)S      -1.3    B7x50R        -5.8      +38.5
21 04.5   J+3            -2.9    B7x50R        -7.4      +44
The brightness observations are Pogson step and fractional estimates. These were obtained by estimating the Moon's total magnitude as seen through a instrument held backwards with stars and planets as observed with the unaided eye. The observed magnitudes are calculated directly from these brightness estimates.

The following comparison objects were used (V magnitudes): J = -2.6 (Jupiter), S = 0.0 (Saturn), A = 0.08 (Capella), B = 0.38 (Procyon), C = 1.14 (Pollux), D = 1.59 (Castor), E = 1.93 (Gamma Gem), F = 2.23 (Delta Ori), G = 2.85 (Zeta Per), H = 3.00 (Zeta Tau). The stellar magnitudes were taken from Yale Bright Star Catalogue (5th edition), while those of Jupiter and Saturn were obtained from The Astronomical Almanac.

My instruments were a reversed 70-mm refractor using 24x (denoted L24x70R in the table), and reversed 7x50 and 7x35 binoculars. Using the 7x binoculars the magnitude reduction was empirically determined as about 4.5 mag., while the telescope at 24x showed a further reduction of approx. 2.7 mag. The Moon's total magnitude was found by subtracting these corrections. The final magnitudes should be correct to within 0.2-0.5 mag.

The last column (deltaT) shows the time from mid-eclipse in minutes. It thus appears that the Moon was about as bright as Jupiter at mid-totality, whereas it was about a magnitude brighter at the start and end of the total phase. Therefore, this was a bright eclipse. During mid-totality the Moon appeared about as red as Betelgeuse in Orion and surface markings were visible without difficulty. The Danjon value was estimated as L = 3.

A fairly bright star (63 Gem at mag. V=5.2) was occulted by the Moon during totality. Using the 70-mm refractor I observed the disappearance at 20h33m16s and reappearance at 21h03m17s UT. In addition, two stars at mag. 6.5 and 7.2 were occulted during the eclipse.

Due to favorable weather, convenient time and a large public interest this eclipse was widely observed through Norway. Several public star parties were held. Norwegian Astronomical Society's public event at the television tower at Tryvann probably attracted more than 3000 persons! This was the last total lunar eclipse fully visible from Norway for nearly three years."

Gunnar Glitscher, Darmstadt, Germany, writes: "I estimated the total brightness at 20.25 UT to be -3.4 mag. The brightness estimate was made with a reversed 6x30 bino and because of the scattered cirrus clouds only Beta Gem was used as a comp. star. This worked very well, because the moon was near to it and there was no difference between the stars' naked eye brightness and the brightness of the moon as seen through the instrument. On the Danjon scale I would estimate the eclipse as '3'. However the outer parts of the umbra have been quite bright (Danjon 3-4) and the inner part '2-3'. The typical colour was an orange-red tint (not a 'pure' orange, but a mixture of red and orange). The outer umbra was coloured nicely yellow. My impression was, that there was a remarkable difference in brightness between the umbras' inner and outer parts. I too tried to make a direct comparison of the moon and Jupiter, by defocussing the planet by some 'eyelens-acrobatics'. Using this crude method the moon appeared to be not very much, but noticeable brighter than Jupiter (less than one magnitude). It was very interesting to follow the event during the phases with different absorption by changing cirrus layer. When the cirrus was quite dense, the totally eclipsed moon became very dim and looked very different than at times with good transparency. There were lots of postings on the astro-lists and one clearly could see, that many observers with much cirrus were a bit disappointed and called the elipse a 'dark' one. Obviously many weren't aware of the great influence of the meteorological conditions."

Kamil Hornoch, Lelekovice, Czech Republic, reports results using a 1x50 monocular:

2001 (UT) mag Jan. 9.852 -2.2 Jan. 9.856 -2.3 Jan. 9.859 -2.5 Jan. 9.860 -2.7 Jan. 9.863 -3.2 Comments: "Totally eclipsed Moon was bright with red-brown colour. I was observing in holes between clouds; sky was in holes very clear. From begin of total eclipse to Jan. 9.851 the Moon was cloud capped... Differential atmospheric extinction was very small. Comparison objects used for deriving magnitudes of the Moon: Jupiter -2.7 mag; Saturn -0.03 mag."

Javor Kac, Slovenia, provides the following results by his group observing from Zaplana (800 m elevation) [also see their MBK Team web site].

After first contact, the lunar rim is reported to be readily visible in the umbra (in contrast with the 2000 Jan 21 eclipse). After the beginning of totality, the edge of the umbra appeared orange to yellow with the other portion of the moon being bright red (L=3.4). During mid-eclipse the brighter rim almost completely disappeared while the darkest part of the Moon was brownish in color (L=2.8). At the end of totality: L=3.3. This eclipse was judged to be brighter than 2000 Jan 21, but darker than 1997 and 1996 eclipses. The Lunar magnitude dimmest value (mag -1.3 to -1.4) was achieved close to mid-eclipse. The naked eye limiting magnitude during mid-eclipse was 6.5-7.0 (depending on observer).

All times are UT. A value of 4.23 was subtracted from the [reversed binoculars] estimated magnitudes to get the final Lunar magnitude.

Jure Atanackov using reversed 7x50 binocular:

UT Lunar mag 1803 -11.3 1818 -11.3 1827 -11.3 1844 -10.8 1853 -9.8 1903 -9.3 1907 -7.8 1932 -6.3 1937 -5.8 1942 -4.7 1947 -3.4 1957 -2.8 2002 -2.7 2007 -2.1 2022 -1.4 2027 -1.8 2032 -1.8 2037 -1.9 2042 -2.5 2047 -2.6 2052 -2.8 2057 -3.5 2102 -4.2 2107 -6.8 2112 -7.4 2117 -8 2122 -8.2 Javor Kac using reversed 7x50 binocular: UT Lunar mag 1952 -3.0 1958 -2.7 2006 -2.3 2008 -1.9 2014 -1.4 2022 -1.5 2036 -1.6 2048 -2.6 2053 -3.0 2058 -4.7 2105 -6.5 2113 -8.2 Javor Kac using reflective sphere (diameter cca. 4 cm, limiting magnitude cca. 0), all comparisons with Jupiter.

UT Lunar mag 1946 -5 2004 -2.3 2016 -2.5 2024 -2.3 2054 -4

Timo Karhula, Lycksta, Västerås, Sweden [lon +16.55, lat +59.65], reports: "The estimates were made a few minutes after totality began and a couple of minutes after maximum. Naked eye estimates (I'm nearsighted and thus all the bright stars become almost as big as the Moon without glasses) as well as estimates through reversed binoculars were conducted.

I could see the penumbra naked eye from 18:31 UT until 22:13 UT. Occultations of the stars SAO79386 (6.5mag) and 63 Gem (5.2m) were timed. Also the star GSC1359:2126 (11.0m) was occulted but was not timed. I observed a very near graze of SAO79396 (9.4m) which was only 2"-3" as closest to the Moon's southern limb as seen with an 8-inch reflector at 90 power."

Time (UT) Mag   Instrument                  Comparison objects
19:57     -2.7  naked eyes                  Jupiter
19:58     -2.5  reversed 8x26 binoculars    gamma Gem
20:24     -1.8  reversed 10x40 binoculars   epsilon and xi Gem
20:30     -1.5  naked eyes                  Jupiter and Capella

(magnitudes for obs with reversed binoculars already corrected)
"The weather conditions were good. Limiting magnitude ~5.8 during totality. Temperature, ~ -3 C. There was a very slight haze giving a 5-degree large 'corona' around the Moon during the partial phases. After the eclipse, the oval N-S 'corona' was colourful, with red farthest out and then green and blue. It reminded me of a pollen-halo. Strange! In my opinion, it was a rather bright eclipse, since one could easily see the limb in the umbra naked eye before 19:08 UT (26 minutes after umbral contact)."

Andrew Pearce, Nedlands, Western Australia, [Lon 115 deg 48m 53s E; Lat 31 deg 58m 16s S; Height above Sealevel: 30m (approx)], made the following magnitude estimates using reversed 6x40 binoculars [4.0 mag correction aplied].

Time (UT)  Mag Estimate      Danjon Scale
19:50      -1.0                     
20:03      -0.7              2
20:14      -0.1              2
20:23      -0.2              2
20:27      -0.5              2

Comparisons stars:

Pollux:         1.2
Castor:         2.0
Delta Gem:      3.5
Zeta Gem:       4.0
Chi Gem         3.6
"The observations at 20:23 and 20:27 were very difficult as the sky was getting very bright by this stage and the comparisons stars were hard to see with the naked eye and the Moon in the reversed binoculars.

Overall it was quite a dark eclipse with the moon appearing as a very deep rust red with a brighter umbral edge. It appeared fairly similar to the eclipse in July 2000."

Ala' Shahin, near Dubai, United Arab Emirates, reports: "I was fortune because the sky was clear during the eclipse though it was raining before and after! I escaped the city lights by going into the desert to guarantee I get black background for my photos. The moon was almost at zenith however this was not very comfortable for photography. I observed about 60 km east of Dubai city in the United Arab Emirates.

Magnitude Estimates:

- Danjon Scale:

I estimated the moon to be L = 3 there was a bright yellow rim on the edge of the moon while a reddish copper colour on the rest of the disk.

- Reversed binocular method:

I used 7x50 binocular for the estimate. I compared the eclipsed moon at mid totality (20:20 UT) with Gamma Gemini (V 1.9) and Mu Gemini (V 2.9). I found the eclipsed moon brightness to be in between these two stars. I estimated it to be V 2.4. However, taking a reduction factor of 4.2 this will result in a stellar magnitude of V -1.8 at mid totality.

- "Near-sighted" method:

I took off my glasses and compared the out-of-focus image of the eclipsed moon with Saturn (V 0.0), Jupiter (V -2.7) and found it to be brighter than Saturn and dimmer than Jupiter but closer to Jupiter.


I managed to take a series of 11 pictures illustration the different phases of the eclipse. I used a 3.5" F/5.6 Maksutov-Cassegrain telescope as a 500 MM telephoto lens on fixed tripod. I shot two Fujicolor Reala 100 for the phase progression to make use of the fine grain and Fujicolor Superia 800 at totality to keep exposure time below 2 seconds.

Oddleiv Skilbrei, Honefoss, Norway (60.2 deg. N, 10.2 deg. E), reports [via B. H. Granslo] the following results using reversed 7x50 binoculars.

 U.T.  Obs. mag.  Estimates     Lunar mag.
19:52    +0.6     A-5;B-1;C+5     -3.6
20:07    +1.7     D-1;E+3         -2.5
20:18    +1.8     D-2;E+2         -2.4
Comparison stars (using V magnitudes from the 5th edition of Yale Bright Star Catalogue): A = 0.08 (Capella), B = 0.38 (Procyon), C = 1.14 (Pollux), D = 1.59 (Castor), E = 1.93 (Gamma Gem).