Table of Contents
Advertisement
the stars you are centering in the eyepiece. Remember, the
finder scope (and main telescope eyepiece, for that matter)
gives an inverted image, so you must keep this in mind when
star hopping from star to star.
8. Astrophotography
There are several different types of astrophotography that can
be successfully attempted with the SpaceProbe 130mm EQ.
Moon Photography
This is perhaps the simplest form of astrophotography, as no
motor drive is required. All that is needed is a t-ring for your
specific camera. Connect the t-ring to your camera body, and
then thread the entire assembly directly onto the end of the
telescope's focuser drawtube.
Now you're ready to shoot. Point the telescope toward the
Moon, and center it within the camera's viewfinder. Focus the
image with the telescope's focuser. Try several exposure
times, all less than 1 second, depending on the phase of the
moon and the ASA (film speed) of the film being used. A
remote shutter release is recommended, as touching the
camera's shutter release can vibrate the camera enough to
ruin the exposure.
"Piggybacking Photography"
Literally thousands of deep-sky objects can be captured on
film with a type of astrophotography called "piggybacking".
The basic idea is that a camera with its own camera lens
attached rides on top of the main telescope. The telescope
and camera both move with the rotation of the Earth when
the mount is accurately polar aligned and an optional motor
drive (Orion EQ-2M Motor Drive, #7827) is engaged. This
allows for a long exposure through the camera without hav-
ing the object or background stars blurred. In addition to the
motor drive, an illuminated reticle eyepiece is also needed. A
t-ring is not needed, since the camera is exposing through its
own lens. Any camera lens with a focal length between 50mm
and 400mm is appropriate.
On the top of one of the tube rings is a piggyback camera
adapter. This is the black knob with the threaded shaft pro-
truding through its middle. The tube ring with the piggyback
adapter on it should be closest to the front of the telescope.
If necessary, remove the tube rings from the equatorial mount
and swap their positions. Now, connect the camera to the pig-
gyback adapter. There should be a 1/4"-20 mounting hole in
the bottom of the camera's body. Thread the protruding shaft
of the piggyback adapter into the 1/4"-20 mounting hole in the
camera a few turns. Position the camera so that it is parallel
with the telescope tube and turn the knurled black knob of the
piggyback adapter counter-clockwise until the camera is
locked into position.
Aim the telescope at a deep-sky object. It should be a fairly
large deep-sky object, as the camera lens will likely have a
wide field-of-view. Check to make sure that the object is also
centered in the camera's viewfinder. Turn the motor drive on.
Now, look into the telescope's eyepiece and center the bright-
est star within the field-of-view. Remove the eyepiece and insert
the illuminated reticle eyepiece into the telescope's star diago-
nal. Turn the eyepiece's illuminator on (dimly!). Re-center the
bright star (guide star) on the crosshairs of the reticle eyepiece.
Check again to make sure that the object to be photographed
is still centered within the camera's field-of-view. If it is not, re-
center it either by re-positioning the camera on the piggyback
adapter, or by moving the main telescope. If you move the main
telescope, then you will need to re-center another guide star on
the illuminated reticle eyepiece's crosshairs. Once the object is
centered in the camera, and a guide star is centered in the reti-
cle eyepiece, you're ready to shoot.
Deep-sky objects are quite faint, and typically require expo-
sures on the order of 10 minutes. To hold the camera's shutter
open this long, you will need to have a locking shutter release
cable; you will need to set the camera's shutter to the "B"
(bulb) setting in order for the locking shutter release to work
properly. Depress the locking shutter release cable and lock
it. You are now exposing your first deep-sky object.
While exposing through the camera lens, you will need to
monitor the accuracy of the mount's tracking by looking
through the illuminated reticle eyepiece in the main tele-
scope. If the guide star drifts from its initial position, then use
the hand controller of the motor drive to "bump" the guide star
back to the center of the crosshairs. The hand controller only
moves the telescope along the R.A. axis, which is where most
of the corrections will be made. If the guide star appears to
be drifting significantly along the Dec. axis, then the mount's
Dec. slow-motion control cable can be carefully used to move
the guide star back onto the crosshairs. Any drifting along the
Dec. axis is due to improper polar alignment, so if the guide
star drifts greatly in Dec., the mount may need to be polar
aligned more accurately.
When the exposure is complete, unlock the shutter release
cable and close the camera's shutter.
Astrophotography can be enjoyable and rewarding, as well
as frustrating and time-consuming. Start slowly and consult
outside resources, such as books and magazines, for more
details about astrophotography. Remember...have fun!
9. Care and Maintenance
If you give your telescope reasonable care, it will last a life-
time. Store it in a clean, dry, dust-free place, safe from rapid
changes in temperature and humidity. Do not store the tele-
scope outdoors, although storage in a garage or shed is OK.
Small components like eyepieces and other accessories
should be kept in a protective box or storage case. Keep the
caps on the front of the telescope and on the focuser draw-
tube when it is not in use.
Your SpaceProbe 130mm EQ telescope requires very little
mechanical maintenance. The optical tube is steel and has a
smooth painted finish that is fairly scratch-resistant. If a
scratch does appear on the tube, it will not harm the tele-
scope. If you wish, you may apply some auto touch-up paint
to the scratch. Smudges on the tube can be wiped off with a
soft cloth and a household cleaner such as Windex or
Formula 409.
15
Advertisement
Table of Contents
