Orion ASTROVIEW 9862 User Manual download pdf (Page 7)

movement of astronomical objects, thereby keeping them

from drifting out of the telescope’s field of view while you’re

observing.

This is accomplished by slowly rotating the telescope on its

right ascension (R.A.) axis, using only the R.A. slow-motion

cable. But first the R.A. axis of the mount must be aligned

with the Earth’s rotational (polar) axis, a process called polar

alignment.

Polar Alignment

For Northern Hemisphere observers, approximate polar align-

ment is achieved by pointing the mount’s R.A. axis at the

North Star, or Polaris. It lies within 1° of the north celestial pole

(NCP), which is an extension of the Earth’s rotational axis

out into space. Stars in the Northern Hemisphere appear to

revolve around Polaris.

To find Polaris in the sky, look north and locate the pattern

of the Big Dipper (Figure 7). The two stars at the end of the

“bowl” of the Big Dipper point right to Polaris.

Observers in the Southern Hemisphere aren’t so fortunate to

have a bright star so near the south celestial pole (SCP). The

star Sigma Octantis lies about 1° from the SCP, but it is barely

visible with the naked eye (magnitude 5.5).

For general visual observation, an approximate polar align-

ment is sufficient:

1. Level the equatorial mount by adjusting the length of the

three tripod legs.

2. Loosen one of the latitude adjusting T-bolts and tighten the

other to tilt the mount until the pointer on the latitude scale

is set at the latitude of your observing site. If you don’t

know your latitude, consult a geographical atlas to find it.

For example, if your latitude is 35° North, set the pointer

to +35. The latitude setting should not have to be adjusted

again unless you move to a different viewing location some

distance away.

3. Loosen the Dec. lock lever and rotate the telescope optical

tube until it is parallel with the R.A. axis. The pointer on the

Dec. setting circle should read 90°. Retighten the Dec. lock

lever.

4. Move the tripod so the telescope tube (and R.A. axis)

points roughly at Polaris. If you cannot see Polaris directly

from your observing site, consult a compass and rotate the

Big Dipper

(in Ursa Major)

Little Dipper

(in Ursa Minor)

Cassiopeia

N.C.P.

Pointer

Stars

Polaris

Figure 7. To find Polaris in the night sky, look north and find the

Big Dipper. Extend an imaginary line from the two “Pointer Stars” in

the bowl of the Big Dipper. Go about five times the distance between

those stars and you’ll reach Polaris, which lies within 1° of the north

celestial pole (NCP).

Figure 6. The equaltorial mount of the AstroView 100 EQ.

Right Ascension lock lever

Right Ascension setting circle

lock thumbscrew

Polar axis finder scope

Right Ascension setting circle

Declination setting circle

Declination lock lever

Front opening

in R.A. axis

Latitude scale

Latitude adjustment

T-bolts

Azimuth fine

adjustment knobs

Right Ascension axis

Declination axis

1 2 3 4 5 6 7 8 9 10 11 12 ... 15 16

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