(meteorobs) Fw: Disintegrating meteor photos

[Ed Majden]

on 3/8/05 12:20, GeoZay at aol.com at GeoZay at aol.com wrote:


 Robs idea  that it is a shaking star image holds
> more water to me than a meteor train. And  Ed's revealing that the camera used
> doesn't have a shutter lock up, means  that the photographer would have had to
> done the equivalent of  the "Mexican Hat Trick" to avoid any shaking stars.
> That is hold  something in front of the telescope for several seconds after
> squeezing off  the cable release and when the vibrations stop, remove the
> object 
> and start  the exposure.
> George Zay
> 
    The standard Canon Rebel 300D does not have mirror lockup.  The Russians
have written a hardware patch that will allow mirror lockup but if this is
done it apparently voids the warranty. It is possible that this camera may
have this hardware patch incorporated.  You have to go to the now
discontinued model D10 or the new D20 to get this mirror lockup feature in
an off the shelf camera.  Incidentally, there is a new D20a introduced in
Japan which has extended red sensitivity which is useful for deep sky
photography.  For normal day time use you must use an IR blocking filter.
This new D20a has not been introduced to the North American market as yet.
I will be testing a D20 for meteor spectroscopy if we ever get some clear
skies here during a new Moon period.  This will limit work to the center of
the visual region of the spectrum as these cameras have poor blue and red
end response.  The main feature I like is your not burning up film while
waiting to record a meteor.  Only tests will reveal if this camera is useful
for meteor spectroscopy.

Ed Majden
Ed Majden