Telescope Mechanical Topics - Knowledgebase Articles

Wedge

A wedge is usually used with a fork mount to tilt your telescope’s azimuth axis at an angle equal to your latitude to point at the celestial pole, so that a clock drive will function properly and the s

What is a clock drive? What is a GOTO mount?

A clock drive is a system of motors and gears used with an equatorial mount. When observing the sky with a properly aligned mount, it compensates for the Eart

What are setting circles?

When you look at an equatorially mounted telescope, you’ll notice dials on both of the axes of the scope. These graduated circular scales are the setting circles and are used to measure or set the poin

Alt-azimuth and equatorial mounts

A telescope mount has two functions. First, it should provide a system for smooth controlled movement to point and guide the instrument. Second, it should support the telescope firmly so that you can view

Does the stated payload weight of my Celestron mount include the counterweights?

No. The payload weight does not include the counterweights.

The payload weight is defined by Celestron’s engineering department

How do I use the setting circles on my Celestron German equatorial mount?

When you look at your equatorially mounted telescope, you’ll notice dials on both of the axes of the scope. These graduated circular scales are the sett

What are the most common bolt sizes for Celestron single and double arm (fork) mount bases and wedges?

A great number of old and new Celestron single and double arm (fork) mounts, tripods and wedges are attached to one another using just two sizes of bolts.

Most mounts are attached to the trip

My backlash settings behave differently before and after alignment. Is there a problem with my mount?

Probably not.

If you adjust your mount’s anti-backlash settings before it is aligned, it is either not tracking or tracking in a different direction that it would when aligned on the sky. Th

What problems are possible when using a dovetail-equipped telescope tube designed for one mount when it’s used with another mount?

The dovetail bar (sometimes called a rail) is one of the great ideas in small telescope design. With the clamp on the mount and a bar on the tube, telescopes (OTAs) and mounts ca

What is periodic error (PE)? What is PEC?

Periodic error (PE) is the name for the inevitable small mechanical errors that occur as the drive gearing in the scope turns. Since these errors are part of the scope’s dr

What is a recommended lubricant for Celestron worm and drive gears?

We recommend Klubertemp -40 to +260 grease or its equivalent, such as Mobil 1 Synthetic Grease.

What do I need to know about mechanical backlash and guiding?

Mechanical backlash is caused by static friction (also called stiction). It happens when your mount makes minor adjustments to its position in the same direction, stopping between each adjustm

What it is magnitude and meaning of the cone error readings given by Celestron German equatorial mounts?

In the hand control menu under Scope Setup, Mount Settings, your Celestron GOTO German equatorial mount displays Cone Value, which is set when one or more calibration stars are a

I’m experiencing motion in RA east after slews with my Celestron German GOTO mount. Is this backlash and how do I correct it?

Yes, it is classic gear backlash.

Gear backlash will often show up on the RA axis at rates above rate 2 when moving east. Worm gears will often show backlash of about

I’m experiencing motion to the east after slews with my Celestron Alt-Az GOTO mount. Is this backlash and how do I correct it?

Yes, it is classic gear backlash.

Gear backlash will often show up on the Az axis at rates above rate 2 when moving east.

Here’s how to fix this

What is precession? Do Celestron mounts correct for it?

Precession is the movement of the north celestial pole (NCP) among the constellations over long periods of time. It’s caused by external gravitational forces from the

What governs the pointing and GOTO accuracy of Celestron mounts? If I’m a RS-232 programmer, what are some suggestions to improve accuracy?

For celestial objects the accuracy of your mount’s pointing is primarily governed by the quality of what’s called the sky alignment matrix. For Celestron’

What is the difference between training and recording periodic error correction (PEC)?

PEC is a means of reducing errors caused by the worm gear of the mount as it turns to drive the mount.

In order to perform PEC, you must first inde

My mount no longer responds to guiding commands in one direction in declination (Dec). What are possible causes of this behavior?

Possible causes include:

1) A burnt out aut