insert the illuminated reticle eyepiece into the diagonal. Turn
the eyepiece’s illuminator on (dimly!). Recenter 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, recenter
it by repositioning the camera on the piggyback adapter, or by
moving the main telescope. If you move the main telescope,
then you will need to recenter another guide star on the illumi-
nated eyepiece’s crosshairs. Once the object is centered in
the camera and a guide star is centered in the reticle eye-
piece, 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 a lock shutter release cable. Set
the camera’s shutter to the “B” (bulb) setting. Depress the
locking shutter release cable and lock it. You are now expos-
ing 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 telescope.
If the guide star drifts from its initial position, then use the
hand controller of the motor drive to “move” the guide star
back to the center of the crosshairs. Any drifting along the
Dec. axis is a result of 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 out-
side resources, such as books and magazines, for more
details about astrophotography. Remember … have fun!
9. Collimating
(Aligning the Optics)
The SkyView Pro 120 EQ telescope has objective lens cell
which incorporates an optical alignment adjustment; this helps
to ensure peak optical performance. Collimating is the
process of aligning the telescope’s optics. In the case of the
SkyView Pro 120 EQ, collimating entails tilting the objective
lens assembly so that the optical axis is precisely parallel to
the telescope’s focuser. The telescope has been collimated at
the factory, so no adjustments to the lens cell are likely to be
necessary. If you are unsure or uncomfortable about making
optical alignment adjustments, we strongly recommend that
you just leave it alone.
Your SkyView Pro 120 EQ comes with a collimating tool.
Figure 15 shows the collimating tool in place.
Use of the collimating tool is best done during the day, either
outdoors or in a well-lit room. Point the telescope at a dark tar-
get of uniform brightness, like a painted wall or a black piece
of construction paper. The distance of the target is unimpor-
tant. You will also need a 2.5mm hex key and a Phillips-head
screwdriver.
Insert the collimating tool into the telescope’s focuser. You will
need to use the telescope’s 1.25" adapter in the focuser.
Secure the collimating tool in the focuser with the thumbscrew
on the 1.25" adapter.
Look into the viewing hole of the collimating tool. You are now
looking straight down the interior of the telescope tube at the
objective lens.
Loosen the securing thumbscrew, and rotate the collimating
tool until you can see the reflection of the of the tool’s reflec-
tive ring in the objective lens. To do this, you will need to point
the wide hole in the collimating tool’s body toward a source of
light. Ignoring the tiny central reflection, you should see two
separate reflections of the ring in the objective lens. If you see
only one reflection, then your telescope is already collimated.
Use the collimating screws in the lens cell to center the reflec-
tions on top of one another (Figure 16). There are three pairs
of screws; each pair works together to tilt the lens. Using your
2.5mm hex key and Phillips-head screwdriver, loosen one of
the screws and then tighten the other in the pair. Look into the
viewing hole of the collimating tool to see if the reflections
have moved closer together or further apart. Once you get the
reflections as close together as you can get with one pair of
screws, move on to another pair.
Continue making adjustments to each pair of screws until the
reflections are precisely centered on each other, which will
give the appearance of one ring. Once only one circular ring is
visible, no further collimation adjustments are needed.
Your SkyView Pro 120 EQ is now collimated. You should not
need to align the optics again unless the telescope is roughly
handled.
10. 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
16
Figure 15.
The collimating tool in the SkyView Pro 120 focuser.
1.25" adapter
Viewing hole
Reflective ring
