As I recall, the Nikon F series use titanium shutters, while others use
cloth shutters, the reason being that vibrations are a problem in general
photography as well as astrophotography. Lightweight shutters with good
damping are common on all well made cameras, and the shutter vibration
should be minimal for astrophotographic use (if you can lock up, or use the
timed delay to lock up the mirror). If your camera's mirror won't lock up,
or the shutter causes enough vibration to ruin the shot, it might be time
to better match your camera to your telescope. Then again, I like the hat
trick - been part of photography since the beginning.

Chris Margaritis


>Hi Andrew, I use an old Nikon FE so this might work for you as well. You
will want to use a cable release of course. Balancing it well will reduce
the amount the scope will react to the vibration. Finally, and hopefully
this will not be specific to my camera, use the shutter release timer. Yup, a
>little known secret is that if you set the timer, the mirror will flip
when the button is pressed and the shutter will activate when the timer
finishes. The mirror vibrations have a chance to dampen down during timer
delay so you just have the shutter vibrations to worry about which I've
found are
>minimal when the scope is well balanced.
>
>Hope this helps,
>
>Glenn Graham
>Analogy, Inc.
>
>----------------------------------------------------
>What I do instead of sleep:
>http://www.rca-omsi.org/rca/members/graham/graham.html
<http://www.rca-omsi.org/rca/members/graham/graham.html>
>
>
> ----------
> Sent: Friday, June 04, 1999 4:56 AM
> Subject: [M]: OT:Astrophotography.
> Importance: High
>
> Hi All,
>
> 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 have just bought
> a set of counterbalance weights which I have not had a chance to try out
> yet.
> Any suggestions?
>
> I plan to start using an autoguider soon with a guidescope and I want to
> eliminate this problem before hand. I'm hoping that the counterbalance
> weights may do the trick, I used to use a piece of cardboard with black
> velvet on it to hold in front of the OTA,
> trip the shutter, then after a few seconds remove the card from the front.
> Culd it be that in the past I didn't have the weights and that it was off
> balance?
>
> Has anybody had similar problems/remedies?
>
> Thanks in advance,
>
> Andy.
>

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