Last night while attempting Quadrantids from the
city, I was contemplating the ratings of Limiting Magnitudes (I am not aquainted
in detail with method of making a rigorous determination). There is a question
involved however that I hope you can answer. The LM on a clear night away from
the city is usually over 6.0 from what I have read here. Discerning a faint
meteor under these conditions is a matter of acuity and practice on the part of
an observer - the rare 6th magnitude meteor being a matter of looking at the
right place and having enough experience to know that you really saw it.
From areas of light pollution it becomes a matter of loss of contrast
rather than acuity. Last night I could barely discern the beehive and three of
the 4 stars surrounding it. It occurred to me that unders these conditions
the observer must integrate the image over a time span to discern the faintest
stars visible. Integrating the image of a meteor over time is not a
luxury we have. It would seem then that rating the LM at 4.0 from the city does
not mean that 4th magnitude meteors are attainable, whereas a 6th mag meteor is
detectable under 6.0 conditions. Does the LM rating them become a sliding scale?
Please feel free to shoot down the incorrect conclusions. I look forward to the
discussion.