(meteorobs) Unusual Fireball Time correction

[Chris Peterson]

Hi George-

The terminology of Moon phases is confusing, and easily misinterpreted. 
In normal usage, you have new Moon, first quarter Moon (half Moon, 
waxing), second quarter Moon (full Moon), third quarter Moon (half Moon, 
waning), and back to new Moon. We are currently just past the first 
quarter Moon, so it is a bit larger than half, and waxing.

Phase is usually expressed as a value of 0-100%, which covers the range 
of new Moon to second quarter Moon, and sometimes expressed as a phase 
angle between the Earth, Moon, and Sun, and given in degrees, 0-180°. 
This is sometimes called the astronomical phase, to distinguish it from 
the more commonly used percentage phase.

The numbers you give are correct, but a quarter Moon isn't the same as a 
half Moon.

Here's what I use for meteor calibration:

Phase Mag
0           (new)
5     -2.6
10    -4.9
15    -6.2  (crescent)
20    -7.2
25    -7.9  (quarter)
30    -8.5
35    -9.1
40    -9.5
45    -9.9
50    -10.2  (half, first quarter waxing, third quarter waning)
55    -10.6
60    -10.8
65    -11.1
70    -11.4
75    -11.6
80    -11.8
85    -12.0
90    -12.2
95    -12.4
100   -12.5  (full, or second quarter)

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message ----- 
From: <GeoZay at aol.com>
To: <meteorobs at meteorobs.org>
Sent: Monday, April 14, 2008 10:57 AM
Subject: Re: (meteorobs) Unusual Fireball Time correction

>>>For a half moon, figure mag -10.2. For the phase last night  (66%) 
>>>figure
> mag -11.1.<<
> Chris, I was of the understanding that the magnitude of a quarter moon 
> (same
> as a half moon I assume), is -8. Crescent moon -6 and a Full moon -12.
> George