Hi Orin,
I was afraid someone would ask for advice on astrophotography... it has
been so long since I have done any serious work in the field.
Hopefully John will read this and can jump in to fill in or correct any
errors on my part. Btw, my sunspot image is slightly sharper than the
b&w print due to the magic of Photoshop's unsharp masking tool. ;)
I am only familiar with a fork mount and thus cannot offer any advice
as to what mount is better. My LX3 came with a finder that allowed me
to roughly set polar alignment which when completed, was more than what
was needed for viewing purposes. I then used the drift method to more
accurately align the scope which is explained in many sources on
astrophotography, my favorite being the one described in
"Astrophotgraphy, A Step-by-Step Approach" by Robert Little. I had a
fairly stable patio deck where I photographed so one evening after
doing an extensive polar alignment, I circled the 3 points where my
tripod met the deck and then in the morning, drilled 3 holes over those
marks and provided three recessed points for the tripod legs to fit
into. As long as I never changed the adjustments on my tripod, I had a
very accurate alignment whenever I set up. I only needed to check up
on it every once in a while by again, using the drift method.
I used the Olympus 1-8 screen and then purchased a 1-12 that others
seemed to prefer to help focus in low light conditions. Even though I
never used one, an Olympus varimagni finder would probably be nice to
have. For deep sky work, I used a Spectra SureSharp focusing device...
not sure if these are manufactured any longer. Instead of trying to
focus the light from a star on the camera's screen, you instead view
the light through a grating in the SureSharp device (this attaches to a
custom connector that replaces the camera's T-ring) and then interpret
the resulting patterns to achieve focus. Once done you disconnect the
SureSharp and attach your camera body. Sounds more complicated than it
really is and works quite well.
I'm not sure how to answer your question dealing with multiple cameras.
I never tried that though I would guess you might run into some
problems depending on how long your exposures are and whether you will
need to manually guide by making corrections in RA and Declination.
Maybe John will offer advice in this area. I imagine the added weight
could be a problem if not balanced properly. It could cause the setup
to shift suddenly if there is any slack in the drive. Also the rule of
thumb is to have a guide star within 2 degrees of whatever you're
photographing otherwise you could get field rotation if the polar
alignment isn't accurate enough. Thus, with multiple cameras covering
a wide field of view I believe you would be more susceptible to field
rotation. Why not use one camera with a wide angle lens pointed at or
slightly away from the meteor shower's radiant point?
Richard
--- Orin Keplinger <orink@xxxxxxx> wrote:
>
> Your photo looks very sharp, Richard.
>
> I am currently trying to get familiar with polar alignment and
> related
> issues of mount type and focus tips. I would enjoy hearing your
> views. I
> have several OM-1s and OM-2s and will be trying for some meteor shots
> during
> the Leonid and Geminid showers this winter.
>
> One of my questions is whether I will get star trails if I put
> several
> cameras on my scope after polar alignment... but the cameras are
> covering
> different areas of sky?
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