Observation - Takahashi Mewlon-180C Instruction Manual

◆ Preparation before Observing
A reflecting telescope like Mewlon-180C
takes time to equalize the optical system
with the ambient outside air temperature,
especially when the outside temperature is
low. Bring the tube assembly outside about
one hour before observation and allow it
to equalize with the outside ambient air
temperature.
◆ Visual Observation
▼Magnification
Magnification can be computed by using the
following formula.
Focal Length of Telescope divided by
the Focal Length of the Eyepiece
For example with LE18mm eyepiece
2160mm / 18mm = 120
Therefore, the shorter the focal length
of an eyepiece is used, the higher the
magnification. On the other hand, the longer
the focal length of an eyepiece is used, the
lower the magnification. It is a general rule
that the upper limit of the magnification is
20x to the aperture in "cm" of a telescope
and the lower limit is 1.4x to it. Therefore,
the highest effective magnification of your
Mewlon-180C will be 360x and the lowest
26x. Most of Takahashi eyepieces can cover
this magnification range.
▼Diagonal Mirror & Diagonal Prism
A diagonal mirror or a diagonal prism make
it easy to observe comfortably. These are 90
degree diagonals, which are available from
Takahashi. Further details of these parts,
please refer to the next page.

Observation

◆ Astro Imaging
▼Magnified Imaging
When imaging the craters of the Moon and
planets, magnified imaging can be done with
the parts optionally available. When imaging
the Moon's surface, you can enjoy a wide
variation of imaging because the Moon has
ample illumination. In the case of planetary
imaging, magnify it as large as possible
according to seeing and illumination. When
the seeing is bad, good imaging of the
moon as well as planets will be impossible.
Therefore, visually check the seeing before
imaging and do it in when the conditions as
good as possible. For magnified imaging,
the TCA-4 is available from Takahashi
together with various T-mounts to attach
your DSLR camera to your telescope.
▼Prime Focus Imaging
This is the method used to image an object
that is focused by placing the imaging
element at the prime focal point. In this
method, a telescope is used as a telephoto
lens for your camera. When Mewlon-180C is
used as a telephoto lens with a camera, its
focal length is so long that it will make star
images degraded with even a slight error
in guiding. Use a sturdy, quality equatorial
mount like the Takahashi EM-200 T-2Z.
Cameras that can do prime focus imaging
are the DSLR and CCD cameras available
in the astro market. Various adapters to
attach a camera to Mewlon-180C are
available from Takahashi. Please refer to
the system charts for further information.
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