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

Each configuration of the Tessaro Bedrock GoTo alt-az mount uses the same mount head; the options change what it stands on and what ships with it. 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. The portable power pack runs the motors of the mount through a full night away from mains power.

The anodized black finish hides scratches and does not reflect the light of a red flashlight back at you. The 2023 edition uses the same gears and bearings as later years, with small differences in the clamps. Check the saddle type in the specifications against the dovetail bar on your telescope before you choose a configuration.

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
• 12 V lithium power pack with cable

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.