[Prev][Next][Index][Thread]
Re: (meteorobs) Dim Meteors vs. Hallucinations
Michael Jablonski responded to a recent thread begun by Chuck Urrey:
>the possibility of detection. One morning I tried to informally test the
>hypothesis that these were meteors that were possibly fainter than the
>calculated LM by fixing my gaze on a portion of the sky while trying to
>detect faint meteors to either side of my line of sight. I convinced myself
>that I was in fact seeing some very faint meteors.
I'm afraid there may be some confusion popping up here? If you are properly
measuring your Limiting Magnitude - that is, the faintest stars you can see
at the ZENITH using easy AVERTED VISION - then you will NEVER (EVER) see a
meteor that is fainter than your LM... That is the whole point of LMs.
In fact, I find that I never see meteors fainter than about LM-0.5. And as
I mentioned in a previous post, the number is far more often LM-1 or even
LM-1.5! Seeing a meteor of mag "LM+1" indicates that your LM is not well
measured, not that you are seeing meteors fainter than your (true) LM.
For example, I'm not sure how light-polluted downtown Atlanta is, but I've
measured my LM while waiting for a bus in downtown Boston (across the street
from Quincy Market, standing under a tree lit with eternal Christmas lights)
as deep as 3.5! Even looking directly INTO a street light from immediately
below it, you should be able to get at least a glimpse of Jupiter somewhere
behind it - which would then have to imply an LM better than -3 anyway...
PS: Regarding the test you suggest, Michael, keep in mind that the number
of actual meteors jumps by a factor of 2 to 3 with each fainter magnitude
step. However, your chance of DETECTING meteors fainter than a certain mag
falls even faster - perhaps by as much as 90-95% at the lowest mag class.
Clear skies all,
Lew Gramer
To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html
References: