Re: [ATM] Dark Sky Meter with Motion Sensor

[Dominic-Luc Webb <dlwebb@canit.se>]

> consideration, but high-altitude turbulence would be a
> nice thing to measure.
>
> I suggest a small-ish telescope (6" Newt) with a long
> focal ratio (3x or higher Barlow), a bright star, and
> some high magnification (max it out) attached to a
> motion detector to measure the turbulence.


I have a read a little on this subject. It seems that
much of the atmospheric scintillation occurs at around
45 Khz (they measure as frequency), so people making
photometric recordings try to stay away from here. One
was I note this is measured uses a spectrum analyzer.
Perhaps a sound card could be used.

Motion detector sounds like make OK idea. I wonder if they
usually operate at such frequencies?

Also, I am concerned about the use or choice of a star because
people who are most fussy about this measurement seem to be
people involved with measurement of stellar scintillation. I
have wanted to make this measurement with satellites as they
pass overhead and in some cases comparing to aircraft simultaneously
passing close to same position. I managed this last year using
the International Space Station and a commercial aircraft passing
within the same optical field at same time. I have yet to figure out
best way to process such data, but the point here is that it is
possible to fetch values from such altitudes. If properly planned,
it could be done several times per evening (around here anyway). Of
course, the best question to ask at the moment is what are you trying
to measure (sample rate, wavelength()s, etc)?


Dominic-Luc Webb

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