May 4^th 2004 Total Lunar Eclipse

 

   Observation Report by Helio C. Vital

 

Location: Tijuca, Rio de Janeiro, RJ, Brazil (Lat-Long-Height:  -22° 55' 21" , -43° 13' 42", 30m)

Time Span:  from 20:55 till 21:43 UT

Local Rise Time of the Moon: 20:21 UT

Atmospheric Conditions: good stability but very poor seeing due to dry fog and high cirrus clouds just above the horizon. Thick Clouds prevented observation after 21:43 UT.

First Visibility of Moon: 20:55 UT (naked eye) - totally eclipsed Moon first noticed only 6 degrees above horizon

 

Totality

Prevailing colors of the lunar disk: mostly copper-like; greenish-yellowish band next to the umbral border at U3

Apparent brightness of the totally eclipsed Moon: approximately equal to that of Jupiter at 21:04. Accounting for the light extinction differential (-1.6±0.4), that means that the Moon was shining at -2.2 + -1.6 = -3.8 (±0.4). However,  from our light curve of the 2003 May 16^th eclipse, we gather that 4 minutes before U3 a +1.2 (±0.3) correction is required to yield the magnitude of the Moon at mid-totality, that yields m= -2.6 (±0.5). Our correlation based on many previous eclipses predicted -1.7 (±0.5)(1σ). That figure, if confirmed, would mean that the Moon remained significantly brighter than expected during totality, maybe an indication that a below-average stratospheric concentration of volcanic aerosols was probed over mid-southern latitudes.

Visibility of the lunar disk: some major features and the entire limb were noticed through the C8.

 

 

Partiality

Features of the umbral border: well-defined (probable indication of no major ozone depletion at mid-southern latitudes)

Crater Timings during Emersions: Five mid-crater timings have been made as shown in the table below. Apparently, in good agreement with predictions based on a 2% atmospheric umbral enlargement. Very poor contrast prevented timings to be made before 21:22 UT and so did a thick blanket of stratus clouds after 21:43 UT.

 

  

Authors_Photos

Index

 

Copyright@2004 Helio C. Vital