What happens to the autoguider thought if you are using it through an OAG?
Would it not lose track of the star? I am using the camera on the 'B'
setting.

Cheers,
Andy.

> -----Original Message-----
> Sent: 04 June 1999 13:40
> Subject: Re: [M]: OT:Astrophotography.
>
> In a message dated 6/4/99 7:55:16 AM Eastern Daylight Time,
>
> << Can anyone tell me the best way to eliminate shutter vibrations of the
> OTA
> whilst doing astrophotography?
> I have a 10" Lx200 and I'm using a Nikon FA 35mm camera >>
>
> I don't think the FA has mirror lockup, but if it does, that's a first
> step.
>
> Shutter and mirror vibrations are only a problem in fairly short exposures
>
> because: for long exposures (over 1/2 second or so) you can use the "hat
> trick" of holding a hat (or piece of cardboard) past the end of the tube,
> tripping a Bulb or Time exposure, and using the hat as the real shutter.
> For
> fast exposures such as 1/250 or faster, it's also a non-problem due to the
>
> shutter speed. That middle ground of 1/125 to 1/4 is more problematic.
> Mirror lockup and "hand holding" a rigidly mounted camera both help.
> Squeeze
> the camera with both hands, press your face against it, or do anything
> else
> you can to reduce vibration, just as when you hand-hold a telephoto lens
> for
> "normal" photography. You'd think that breathing and shaky hands would
> hurt,
> but it turns out they have fairly low frequencies, and you can apply a lot
> of
> damping for the higher-frequency vibrations of the mirror and shutter.
>
> Good Luck!
>
> John

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