Re: [APML]: Why Om-1

["Bobby Middleton" <bobbym@webwide.net>]

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> From: Kip Peterson 
> 
> For those astrophotographers who use a camera which does not provide a 
> mechanical mirror lock-up, does the vibration induced by releasing the 
> shutter significantly impact the quality of your images? If so, is it 
> possible to "hide" the film by holding the telescope's lens cap (or 
> something) near the scopes objective, waiting for the vibration to cease,

> then quickly "removing" the cover without deleterious effects to the 
> image?

Vibration from the mirror slapping up can induce vibrations that will lower
resolution in some cases.
The mirror lock-up is helpful on brighter objects such as the moon,
planets, and some of the brightest stars. I do not use the lock-up
on dimmer, long-exposure deep sky stuff, and I don't think my pictures
suffer from its non-use. [Someone speak up if they know better]  
As for the use of something held in front of the telescope, you're talking
about what's called the "hat-trick"; use a black piece of cardboard held
just in front of the end of the telescope while the shutter is tripped,
then remove it after the vibrations have dampened out. 

Bobby Middleton

astropics at: http://www.webwide.net/~bobbym/astro1.htm