Catharina Lunar Light Ray

Initial Reports

Date:  19 Jul 03
Time:  approx 0900 - 0920 hrs UT
Location:  Kingston, Ontario, Canada
Instrument:  102 mm F/9.8 achromatic refractor with Sirius Optics MV-1 filter
Magnification:  100 X to 165 X
Seeing:  5/6

Details: observed a prominent sunset ray across the floor of Catharina. Ray oriented approximately SE to NW.Appeared, to visual observation, to be aligned with a prominent but narrow dark break in the illuminated eastern rim of Catharina. When first detected the ray spanned approximately 75% of the width of Catharina, shrinking to approximately 50% by the end of the observation. Clear Skies!
James Greengrass


The Initial Predictions, Using Data in Original Reporting

The longitude and latitude of Kingston, Ontario are: 76o 30' W and 44o 16' N , respectively

Starting Date = 2003/7/1 at 00:00 U.T.

Site Longitude = +76.500
Site Latitude = +44.270


Feature = CATHARINA
Feature Longitude: = +23.600
Feature  Latitude: = -18.000

Reproducing Lighting For: 2003/7/19 at 09:00 U.T.

Desired Solar Altitude =  +2.170(Setting),  Azimuth = +272.154
Average Co-longitude =  154.119
In the Time column, D=Daylight, T=Twilight

                      ---- Moon's ----    -- Earth's --
                        Topocentric        Topocentric      -------- Sun's --------
   UT Date    Time     Alt°   Semi-Diam''  Long°   Lat°     Colong°     Lat°    Azim°

 2003/07/19  09:00T  +42.956    917.38    +4.814  +5.961    153.670   +1.377  +272.154


Crater Description:

Catharina - +378,-310: A great but somewhat irregular walled-plain, about 55 miles in diameter, with broad walls torn by explosions and much deformed by depressions (the largest of which lies on the inner north-west slope, but still attaining 16,000 feet in places. A very prominent valley runs down the inner west slope and is, in part, a crater-chain. The outer north-west slope is altogether deformed by valleys and a mass of depressions, intruding upon wah other. The crest of the wall on the south-east and south is disturbed by small craters; on the outer slopes, among numerous craters, is the ring C connected to Polybius by a ridge and to Catharina by a valley. - Wilkins and Moore, The Moon, Faber & Faber, 1955

crater map crater image


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