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POLAR ALIGNMENT TELESCOPE (PASILL4)

This is our current model which began shipping in November 2005. It has an updated reticle good through 2030.

It fits all 400, 600, 600E, 800, 900 and 1200 models (except the original black 1200s) and the new Mach1GTO.

PARTS LIST

Polar Alignment Telescope with two covers

Battery pouch, including:

Illuminator with cable

Battery holder with cable and two AA batteries

0.9mm Allen wrench

27.5" Cable to power the reticle from your Astro-Physics mount (part # CABPAS3)

POLAR ALIGNMENT TELESCOPE

This Polar Alignment Telescope (also called a polar axis telescope, polar finder or polar scope) will help you to align

your mount with the Celestial Poles. When your mount is properly aligned, your telescope's drive will accurately

track celestial objects as they pursue their daily motion across the sky. This will allow you to keep the object you are

viewing in the center of your field-of-view, and eliminate the need for manual adjustments. This polar scope can be

used in both the Northern and Southern Hemispheres.

THE RETICLE

Your Polar Alignment Scope has a new reticle, designed for accurate alignment from 2005 until 2030. Two

alignment stars have been added for the Southern Hemisphere to help with the trickier alignment faced by those of

you who are "down under."

Why did the reticle need to be updated? We think of the stars as being fixed in space, but this is not the case.

There are two principal ways in which the stars' motions require us to periodically revise the reticle for accurate

alignment. First, and most important, is actually our planet's fault. The earth's tilted axis precesses like a spinning

top that has been bumped. It's axis traces a circle in the sky every 26,000 years or so. This means that the actual

pole's position is constantly changing with respect to distant stars, albeit very slowly. (It also means that in 13,000

years, our distant ancestors will have exactly reversed seasons.) Second, the so called fixed stars, along with our

sun, are actually whirling around the gravitational center of our galaxy in various elliptical orbits. Because of this,

each star has its own proper and apparent motion in the sky relative to every other star. These motions are

generally not noticeable to the naked eye, but they can be enough to affect the accuracy of star charts and reticles

over a period of years.

Why do Polaris and

Octantis only have one radial line in the reticle and why do they move within their

gaps from epoch to epoch? Polaris in the north and

other stars must be related in order to arrive at the true pole. This is done to simplify the alignment process. As

their positions relative to the actual pole change in right ascension, the other stars' radial lines are adjusted to

compensate. However, there is no way to also compensate for their changes in declination, so a gap is required

along their respective radial lines. As their declinations change over time, their positions within these gaps must

also change accordingly. During the 25 years covered by the reticle, Polaris' declination will increase by about 6

minutes of arc, while

Octantis' declination will increase (become less negative) by about 7 minutes.

Polar Axis Scope Specifications:

Objective lens: 15 mm

Field of View: 10°

Objective lens

ASTRO-PHYSICS, INC.

Focusing Adjustment Locking Ring

(under A-P adapter)

Octantis in the south are used as pivot stars to which the

Astro-Physics adapter

Collar

Preset locking screw

Reticle plug

Diopter eyepiece

Reticle housing

Aligning adjustment

setscrew (1 of 3)