Instruction manual

21
Figure 7-1
ight Time Star Collimating
fter successfully completing daytime collimation, night time star collimation can be done by closely
re beginning
):
ike the North Star (Polaris). It can
mary mirror, locate the collimation screws on the rear of the telescope tube.
ook into the focuser and notice if
he secondary reflection has moved closer to the center of the primary mirror.
Aligning the Primary Mirror
Now adjust the primary mirror screws to re-center the reflection of the small secondary mirror, so it’s silhouetted
against the view of the primary. As you look into the focuser, silhouettes of the mirrors should look concentric.
Repeat steps one and two until you have achieved this.
Remove the collimating cap and look into the focuser, where you should see the reflection of your eye in the
secondary mirror.
N
A
adjusting the primary mirror while the telescope tube is on its mount and pointing at a bright star. The
telescope should be set up at night and a star's image should be studied at medium to high power (30-60
power per inch of aperture). If a non-symmetrical focus pattern is present, then it may be possible to
correct this by re-collimating only the primary mirror.
Procedure (Please read this section completely befo
To star collimate in the Northern Hemisphere, point at a stationary star l
be found in the north sky, at a distance above the horizon equal to your latitude. It’s also the end star in the
handle of the Little Dipper. Polaris is not the brightest star in the sky and may even appear dim, depending
upon your sky conditions
.
Prior to re-collimating the pri
The rear cell (shown in Figure 7-1) has three large thumbscrews which are used for collimation and three
small thumbscrews which are used to lock the mirror in place. The collimation screws tilt the primary
mirror. You will start by loosening the small locking screws a few turns each. Normally, motions on the
order of an
1
/
8
turn will make a difference, with approximately a
1
/
2
to
3
/
4
turn being the maximum required
for the large collimation screws. Turn one collimation screw at a time and with a collimation tool or
eyepiece see how the collimation is affected (see the following paragraph below). It will take some
experimenting but you will eventually get the centering you desire.
is best to use the optional collimation tool or collimating eyepiece. L
It
t