Celestar Manual
Celestial Photography
56
As you perfect your technique, try specialized films, that is films that are designed or specially treated for
celestial photography. Here are some popular choices:
•
Ektar 125 (color print)
•
Fujichrome 100D (color slide)
•
Tech Pan, gas hypered (black and white print)
•
T-Max 400 (black and white print)
As with all forms of photography, keep accurate records of your work. This information can be used later
if you want to reproduce certain results or if you want to submit photos for possible publication.
Once you have mastered piggyback photography with wide angle and normal lenses, try longer focal
length lenses. The longer the focal length, the more accurate your guiding must be. You can continue to
increase the focal length of the lens until you are ready for prime focus photography with your Celestar
telescope.
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 for this process; one to release the camera shutter and one to
hold the card. Here's the process for making the exposure.
1.
Find and center the desired target in the view finder of your camera.
2.
Turn the focus knob until the image is as sharp as possible.
3.
Place the black card over the front of the telescope.
To Next Page
Loading...
