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10
1. Center the Moon in the field of your telescope.
2. Focus the telescope by turning the focus knob
until the image is sharp. Make sure the mirror
lock knobs are loosened.
3. Set the shutter speed to the appropriate setting
(see table below).
4. Trip the shutter using a cable release or self
timer.
5. Use your camera's bracketing feature to
automatically change exposure time in order to find the best exposure.
Lunar Phase ISO 50 ISO 100 ISO 200 ISO 400
Crescent
1/2 1/4 1/8 1/15
Quarter
1/15 1/30 1/60 1/125
Full
1/30 1/60 1/125 1/250
The exposure times listed in table 7-1 should be used as a starting point. Always make exposures that are longer
and shorter than the recommended time. Also, take a few photos at each shutter speed. This will ensure that you
will get a good photo.
This technique is also used for photographing the Sun with the proper solar filter.
Eyepiece Projection
This form of celestial photography is designed for objects with small angular
sizes, primarily the Moon and planets. Planets, although physically quite
large, appear small in angular size because of their great distances. Moderate
to high magnification is, therefore, required to make the image large enough to
see any detail. Unfortunately, the camera/telescope combination alone does
not provide enough magnification to produce a usable image size on film. In
order to get the image large enough, you must attach your camera to the
telescope with the eyepiece in place. To do so, you need two additional
accessories; a deluxe tele-extender (#93643), which attaches to the visual
back, and a T-ring for your particular camera make (i.e., Minolta, Nikon,
Pentax, etc.).
Because of the high magnifications during eyepiece projection, the field of
view is quite small which makes it difficult to find and center objects. To make the job a little easier, align the
finder as accurately as possible. This allows you to get the object in the telescope's field based on the finder's
view alone.
Another problem introduced by the high magnification is vibration. Simply tripping the shutter
even with a
cable release
produces enough vibration to smear the image. To get around this, use the camera's self-timer if
the exposure time is less than one second
a common occurrence when photographing the Moon. For
exposures over one second, use the "hat trick." This technique incorporates a hand-held black card placed over
the aperture of the telescope to act as a shutter. The card prevents light from entering the telescope while the
shutter is released. Once the shutter has been released and the vibration has diminished (a few seconds), move
the black card out of the way to expose the film. After the exposure is complete, place the card over the front of
the telescope and close the shutter. Advance the film and you're ready for your next shot. Keep in mind that the
card should be held a few inches in front of the telescope, and not touching it. It is easier if you use two people
Table 3-1
Above is a listing of recommended exposure times when photographing the Moon at the
prime focus of your telescope.
Figure 3-3 - Accessories for
Projection Photography
T-Ring (Camera
Model Specific)
T-Adapter
Figure 3-2 – T-Adapter for 11/14" Optical Tube
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