(meteorobs) Greyscaling. a means to measure brightness....Better?

[Swift, Wesley R. (MSFC-NNM05AB50C)[RAYTHEON]]

Larry,

	Indeed, if the meteor is captured with a video camera, one only
has to save individual frames in a format appropriate to MaximDL or any
other program that does circular aperture photometry.  The stars in the
field are then used as references and the camera magnitude established.
That part is easy.   Most of these cameras are best assumed to be
approximately R band rather than V band instruments.   For more precise
work, the color of the reference stars, instrument spectral response and
some suitable reference spectrum for the meteor must be assumed to get
the total and V magnitude of the meteor.   

Wes
 

-----Original Message-----
From: meteorobs-bounces at meteorobs.org
[mailto:meteorobs-bounces at meteorobs.org] On Behalf Of
stange34 at sbcglobal.net
Sent: Saturday, March 10, 2007 12:48 AM
To: meteorobs at meteorobs.org
Subject: (meteorobs) Greyscaling. a means to measure
brightness....Better?

It would seem that a negative image of a wide-band greyscale,  if it
were used on a computer monitor to compare with a meteor or fireball
photo could more precisely determine the objects brightness by
pre-assigning the reversed greyscale with standard objects of
brightness. i.e., full Moon, half, quarter, Antares, etc. which would
have been compared on the same monitor at an earlier time.

Any changes in recent changes in contrast & brightness of the monitor
would effect both the standards(the reversed greyscale), & the meteor
equally. So the calibration would remain unchanged.

The absolute brightness range of a computer monitor is limited. Not
nearly so would be a display on a TV or composite monitor. The
brightness is closer to actual brilliance of an object.

Reading of the "estimates" in reported meteors & fireballs seems a
little loose because it is a momentary view...without benefit of a more
accurate comparison to a fixed object and would be an understandable
estimate.

But, if the object is captured by a video camera of any kind,  and the
image is transfered & projected on a computer or composite monitor....
accuracy should be improved with a fixed(pre-calibrated) scale for
comparison. Little help on this subject was found on the internet.

Has any of this been done to make some kind of standardl?

Larry
YC Sentinel     
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