This page shows the
equipment I have used to obtain the
astrophoto's.
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This was my first
telescope, a Tasco 125mm Catadioptric
Newtonian of 1000mm focal length. I
bought this third hand from an astro
society member. The equatorial mount was
manually driven but proved to be a
problem at high magnification because the
object would race out of the viewfinder.
The accessories were an 18mm plossl and
5mm kellner eyepieces, a 2 x barlow lens,
an SLR camera adapter with the facility
for eyepiece projection. To take any
photo's, I had to use a high film speed
to gain enough shutter speed. Sometimes
the film speed was as much as 1600 ISO! I
constructed a full aperture solar filter
using Baader Solar Safety Film for this
scope. A fellow astro society member made
me an adapter ring out of a piece of
scaffold pole, so that I could take
photo's at prime focus. |
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This my second
telescope, a Celestron C8 SCT. This was
bought second hand from a gentleman at
Heathfield. It has an aperture of 200mm,
a focal length of 2032mm and a focal
ratio of F10. There is a built-in RA
drive, it has optical encoders fitted for
RA and Dec to run the digital setting
circles. Shown in the picture is a 60mm
refractor of 900mm focal length
piggy-backed, which is used as a
guidescope, and a dew shield on the main
tube. I have also a declination motor
which I can fit if required. There is a
hand controller for fine adjustments to
RA and Dec. |
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Here is the
Celestron set up to take solar photo's,
in fact this was taken during the transit
of Mercury in May 2003. Both the main
tube and the finderscope have filters
fitted, just above the finderscope is the
piggy-back camera adaper in place of the
guidescope fixing. The filters are again,
made from Baader Solar Safety Film and
thick card glued with evostick. It has
been constructed in such a way that there
cannot be any light leakage. |
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This is the set up I
used to obtain the photo's of the Transit
of Venus in June 2004. Note the extra
aperture of the solar filter. I added
this for two reasons; it allows more
light through for easier viewing and
shorter exposures; it acts as a Hartman
Mask to aid with focussing. The
guidescope is being used to project an
image into a home-made box so that
constant and safe observations could be
made. I removed the finder-scope from the
refractor so that no accidents could
occur from looking through it. The
projection box was useful to show
passers-by what was happening. The
digital camera was mounted on the
eyepiece and the TV out lead was fed to a
small portable TV to enable me to see the
images more easily. The TV had to be
heavily shaded inside a carboard box to
be able to see the screen. |
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Here, the T-ring and
T-Adaptor are fitted to a Canon EOS 650
camera which has a remote release cord.
Electronic cameras are not ideal when
photographing in cold temperatures, the
batteries are known for giving up
prematurely. So if you can get hold of a
good manual camera it is far preferable.
I use this one because it is the only SLR
I have currently. It has a fairly soft
shutter action but it still can jarr the
telescope. |
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A tele-extender is
used here for higher magnification. This
longer tube fits over an eyepiece at the
back of the telescope tube. |
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Left is a
Digiscoping mount. The rings fit over an
eyepice and is secured by the 6 thumb
screws. The camera is secured by the
larger screw at the bottom of the picture
into the tripod recess on the camera. The
whole assembly is made from stainless
steel and can be adjusted using an allen
key. The company that supplied it is called SRB Film
Service in Luton. They sell just
about any special piece of equipment you
can imagine for cameras and
camcorders. Their website is;
www.srbfilm.co.uk
This link
will take you to an index page. Select
adaptors, then select the page for
digiscoping mount for digicams.
www.srbfilm.co.uk/index1.html
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The Nikon Coolpix
4500 is fitted to the digiscoping mount
together with an eyepiece and remote
release cord. When using this kind of
mount the camera must sit square on, and
centrally to the eyepiece, otherwise some
parts of the picture may be out of focus
or missing. Attach the digiscoping mount
with the camera and eyepiece to the
telescope. This then has to be focussed.
Set the camera to infinity focus then use
the telescope focussing knob in
conjuction with the camera screen on a
bright object. I find that a small
portable TV attached to the TV out socket
of the camera helps with focussing, it
has a larger screen and can be placed in
a convenient position to see. |
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I was able to borrow a Coronado PST from
the East Sussex Astronomical Society where I am a member.
My intention was to use a webcam to image the Sun, but the PST
is manufactured is such a way that a decent focus cannot be
achieved. Views though, were very good, with a small prominence seen
and surface granulation defined. |