Tessaro Bedrock GoTo alt-az mount, head only

Specifications

Description

The Bedrock is a GoTo alt-az mount for heavy catadioptric telescopes, rated for a payload of 22 kg. Its cast head has a broad base and a wide bearing on each axis, which keeps the tube steady at high magnification, where small vibrations show up quickly in the eyepiece. It is built for Schmidt-Cassegrain and long Maksutov tubes that are too heavy for lighter mounts. The mount head weighs 9.4 kg, so it is best moved with the tripod legs and head assembled together.

The hand controller holds a catalog of 42,000 objects and walks you through an alignment routine that uses two or three bright stars. Once aligned, you pick a target by name or catalog number, and the mount slews to it at up to 4 degrees per second on both axes. You can also steer with the directional buttons to center an object by hand. The controller stores recent targets, so you can return to an object in a later session without searching for it again.

Alt-az tracking moves both axes together at sidereal rate, with a correction table that smooths the altitude motion near the zenith. The mount does not follow the sky in equatorial coordinates, so long exposures are limited by field rotation. For visual observing at medium and high power, that limit is rarely reached. Power comes from a 12 V DC supply at 2.5 A through a barrel connector, so the mount can run from a battery pack at a remote site.

Set the Bedrock on a pier or a tripod rated for at least 25 kg, and tighten the leveling bolts until the head sits flat. Balance the tube on the saddle before you start the alignment, because an unbalanced load strains the drive gears and reduces tracking accuracy. Keep the total load, including the diagonal, eyepiece, finder, and any camera, well below the rated payload. Check the saddle clamp after each session, since repeated slewing can loosen it over time.

About this configuration

This listing covers one configuration of the Tessaro Bedrock GoTo alt-az mount, defined by its support, add-on, finish, and edition year. This configuration is the mount head alone, so you supply a tripod or a pier with a matching top plate. Buying the head only makes sense when you already own a sturdy tripod or a permanent pier in the garden. A padded case makes it easier to carry the mount head to a dark site without knocks to the axes.

A white mount head is easy to see in the dark, which helps you avoid walking into the tripod. The 2023 edition uses the same gears and bearings as later years, with small differences in the clamps. The payload rating in the specifications applies to the mount head in every configuration of the Bedrock line.

What's in the box

• Alt-az GoTo mount head with dovetail saddle
• Hand controller with coiled cable
• 12 V DC power cable
• Tripod adapter plate
• Alignment and user guide
• Padded carrying case

Compatibility notes

• Accepts dovetail bars up to 65 mm wide, held by a safety screw on the saddle.
• Suits telescopes with a total load up to about 22 kg.
• Uses a 3/8-16 base thread, and a 1/4-20 adapter is included for smaller tripod heads.