A SINGLE-AXIS PLATFORM, for instance, is quite suitable
for LUNAR AND PLANETARY PHOTOGRAPHY through the main telescope.
PIGGYBACK PHOTOGRAPHY (taking long- exposure pictures with
a separate camera attached to the main telescope) is also easy --
if care is taken to polar-align accurately. Using the hand control
to guide at high power with your main telescope assures good star
images, even with long telephoto lenses. Short exposure PRIME FOCUS
PHOTOGRAPHY can also be done with a Single-Axis Platform. This
is particularly useful to those doing CCD imaging and video camera
photography.
Long exposure PRIME FOCUS PHOTOGRAPHY through the main telescope
requires a fine guiding motion in declination as well as right ascension.
For this purpose I have developed a DUAL-AXIS PLATFORM which
provides an approximate declination motion for a large part of the sky,
especially near the meridian. The hand control gives a backlash-free fine
guiding motion in declination. Also at your fingertips is a fast slew
which, together with the right ascension slew, facilitates centering
objects and sweeping an area at high power.
M13 -- a 10 minute exposure through a 16" f5 Dobsonian on a Dual-Axis Equatorial Platform, Ektar 1000 film.