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Observation
◆
Preparation for Observing
The telescope will take time to temperature
equalize in the cold weather, taking the
telescope from a warm place to the outside.
It is best to take out the telescope about one
hour before observing begins to equalize
with the colder air.
◆
Visual Applications
▼Determining Magnification
The magnification of any eyepiece used with
the telescope can be calculated by using
the following formula.
(focal length of a telescope) divided by
(focal length of an eyepiece)
For example with LE-5mm
530mm / 5mm = 106X
Therefore, the shorter focal length eyepiece
will produce the higher magnification. In
general, the limit of the magnification will
be 20X and lowest 1.4X, respective to the
effective aperture (cm). In the case of FOA-
60, the highest will be 120X and the lowest
8.4X. Therefore, most Takahashi eyepieces
can be used with FOA-60.
▼
Diagonal Mirror & Diagonal Prism
When observing the zenith is necessary, it
is advisable to use a high quality 90-degree
prism. The Takahashi 90-Degree Prism is a
quality multi-coated prism, which allows the
observer to easily view the zenith by looking
down into the prism. The diagonal prism
has a 45-degree light pass and produces an
erect, reversed (mirror) image. The diagonal
prism is designed to be used with 31.7mm
(1¼”) barrel eyepieces.
The light pass length through the prism
becomes longer so the drawtube must be
moved a longer distance. In order to achieve
the best focus, please connect the system
parts as instructed.
◆
Astro Imaging
▼
Prime Focus Imaging
This is the method to take images at the
focal point, just like using a telescope as
a telephoto lens. Since the focal length
of a telescope is far longer than that of a
telephoto lens, even a slight error in guiding
will result in poor star images. Therefore,
a steady mount should be used to keep
images as sharp as possible. A DSLR
camera or a CCD camera can be used for
the prime focus imaging. In order to attach a
DSLR camera, the CA-35 (50.8/2") and the
T-Mount DX-WR are required, according to
the camera model.
▼
Eyepiece Projection Imaging
When the FOA-60 is used to take images
of lunar craters or planets, the TCA-4
eyepiece projection system can be used for
taking magnified images. The magnification
for each eyepiece can be increased or
decreased by moving the sliding tube that
is an integral part of the TCA-4. This device
can be attached to a DSLR camera with the
T-Mount DX-S, which is available for EOS
or Nikon.
In imaging the lunar surface, it is well
illuminated so you can enjoy various images
with various magnifications. For planetary
imaging, make the magnification as high as
possible according to the seeing. When the
seeing is not good, you cannot take good
images either of the moon or of planets.
Check the seeing condition before imaging.
