(meteorobs) Re: The Bortle Dark Sky Scale and meteors?
I feel that your suggestion is an excellent idea. I know for a fact that
my observing sites, especially at home, are rated less than perfect on
the Bortle scale yet I am still able to perceive faint stars. I feel
that this added information could help determine an observer's
perception. Probably not in a exact mathematical sense but enough to
categorize a person as having above or below average perception.
It would be interesting to see if those claiming to have a LM near +7.0
also possess a high rating on the Bortle scale. On the other end of the
spectrum it would also be interesting to see the ratings observers
estimate from home under LM's near +5.0 and worse.
The Bortle Scale is not available on line but is published in the
February issue of Sky & Telescope. For those who do not subscribe to Sky
& Telescope a copy of the February issue should be available is any well
I would encourage all observers to attempt to use the Bortle scale in
addition to your normal limiting magnitude estimates and to share your
results with others.
Lew Gramer wrote:
> A recent thread on a regional astronomy mailing list I belong to mentions
> the excellent article by John Bortle in Sky & Telescope's Feb 2001 issue.
> Many of our readers may have seen the article already. However, for those
> who have not, it argues (rightly, I think) that the Limiting Magnitude and
> other traditional measurements of sky darkness simply fail to accurately
> reflect the visibility of deep-sky and other extended objects. In place of
> these traditional measurements, Bortle presents a simple 9-step scale for
> sky darkness, based on the observed visibility of various specific objects
> and classes of objects, both in the sky and on the ground near an observer.
> My question for 'meteorobs' is this: Although the Bortle scale clearly can
> not and should not ever replace Limiting Magnitude as a calibrating factor
> for visual meteor observations, should meteor recorders in fact begin to
> record the Bortle Scale of the skies under which they observe meteors? The
> argument in favor of this is simply that one can never forsee what value a
> piece of data might hold for future research. And something which purports
> to measure the "quality" of the sky, may some day be useful for those who
> wish to allow the PUBLIC to know what to expect from meteor showers.
> The argument against this, obviously, is that meteor observers are already
> asked to collect a good number of different data items, both about their
> observing conditions and about individual meteors. Adding one more without
> definite good reason may not make sense.
> I'd be interested to hear the opinions of our readers on this!
> Clear skies,
> Lew Gramer
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