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by Dr. Eric Flescher (KCStarguy@aol.com) created 6/3/2000 Updated 11/10/2003 http://members.aol.com/kcstarguy/blacksun/lunar.htm
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Lunar Eclipse Resources EJAWs
ACTION Search THINKING research ACTIVITIES
FOCUS exploration general information about eclipses EJAWs
ACTION Search THINKING research ACTIVITIES
FOCUS exploration learn what causes a lunar eclipse |
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Q: What is the Lunar eclipse darkness measuring scale? A: One of the simplest and most telling total lunar-eclipse observations is estimating the Moon's luminosity value at various times during totality. Early in the twentieth century, the French astronomer André-Louis Danjon devised a clever five-point scale for rating the darkness of a total lunar eclipse. The Danjon scale, reproduced in Table 4.1, has since gone on to become the standard by which all total eclipses are judged.
Danjon Lunar Eclipse Luminosity Scale (More informtion below scale) Danjon
rating Darkness description
simple L = 0.0 Very dark
eclipse. Moon almost invisible,
especially at mid-totality. L = 1.0 Dark
eclipse gray or brownish
coloration; lunar-surfacedetails distinguishable
only with difficulty. L = 2.0 Deep red or
rust-colored eclipse central part in the
umbra dark, but outer rim of
the umbra relatively bright. L = 3.0 Brick-red
eclipse usually with a brighter
(frequently yellow) rim to the
umbra. L = 4.0 Very bright copper-red
or orange eclipse , with a
bluish, very bright umbral
rim. The Danjon scale should be used to estimate the appearance of a total eclipse only with the naked eye. Surprisingly, the often-subtle colors of a total eclipse tend to fade as magnification increases. The late Joseph Ashbrook suggested that this might be due to a reduction in surface brightness to near or below the threshold for color perception.
Although Danjon devised the scale to fit every lunar eclipse, it is rare for an eclipse to match one of his descriptions exactly. Instead, most seem to fall somewhere between two values - therefore, so should your estimate. For example, at mid-eclipse, if the Moon appears a muddy-clay color highlighted with a bright, almost yellow rim, then the Danjon luminosity value would fall somewhere between 2.0 and 3.0. After carefully examining the Moon's appearance, judge which description it most resembles, then prorate the value accordingly. In this case, a luminosity value of 2.4 or 2.5 would seem most appropriate. Astronomical magazines always encourage readers to send in their observations and reports, but to be of real value, always include your time, location, instrument used, if any, and a description of the sky conditions.
A less-often quoted rating system was introduced in 1924 by Willard J. Fischer. The Fischer scale uses a three-point strategy based not on color, but instead, on the amount of surface detail visible through various instruments. Table 4.2 offers a summary.
Fischer Lunar Eclipse Scale
Grade Description 2 The naked eye sees "spots" on the eclipsed Moon, and the seas and other detail can be seen with hand instruments (small binoculars and field glasses)
1 Instruments of 5 cm (2 inches) up to 15 cm (6 inches) are necessary to show detail on the eclipsed surface.
0 Apertures greater than 15 cm (6 inches) are needed to see surface detail.
Phil Harrington Author: Eclipse! http://www.philharrington.homepage.com |
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Send in your lunar eclipse darkness rating (according to the scale above and we will list them here. Send to Dr. Eric Flescher (KCStarguy@aol.com) Your name: ______________________________ Screen name:___________________ Place observing from: City :_____________________ State:_____________________ Your rating number for the eclipse at mid totality Danjon) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 the reason for your rating-explain (colors, brightness etc) : ________________________________________ |
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Lunar Eclipse photography exposures with 35 mm Choose what you want to shoot and set you aperature and speed to these settings no filter required. Tripod recommended These recommendations modified from Astrophotgraphy Basics by Kodak (P-150)
If you wold like to try to photograph the eclipse try stage of
eclipse asa fim
speeds higher ASA
faster it is but more grain faster
film 25-32 64-80 100-125 200 400 full
moon 1/250 at
f/5.6 1/250 at
f/8 1/250 at
f/11 1/250 at
f/22 1/250 at
f/22 up to first
contact 1/60 at
f/5.6 1/60 at
f/8 1/60 at
f/11 1/60 at
f/16 1/125 at
f/16 2nd 3rd
contact 2 at
f/2 1 at
f/2 2 at
f/2.8 2 at
f/4 1/4 at
f/2.8 mid
totality 8 at
f/2 4 at
f/2 2 at
f/2.8 1 at
f/2.8 1 at
f/2.8 |