Northmere Crag GoTo alt-az mount, head only

Specifications

Description

The Crag is a heavy-duty GoTo alt-az mount rated for loads up to 15 kg. It moves in altitude and azimuth, so you aim it the way you would aim a camera, and its handheld controller can slew to any of the 40,000 objects in its database. The head weighs 9.5 kg, which keeps the mount steady under a long refractor or a large Newtonian once the tube is balanced on the saddle.

Worm-gear drives on both axes move the tube in small steps and follow the sky at the sidereal rate during tracking. After a short alignment on two or three stars, the controller builds a pointing model that improves accuracy across the sky. Alt-az tracking introduces slight field rotation over long exposures. That effect is rarely visible during visual observing, but it matters if you attach a camera and expose for several minutes.

The saddle is a universal dovetail saddle, 76 mm (3 in) wide, held by two clamps. It accepts refractors, reflectors, and binocular bars. Keep the total load, including diagonal, eyepiece, finder, and any camera, well below the rated 15 kg. Balance the tube along the saddle before you start the GoTo routine, because an unbalanced load strains the drives and reduces tracking accuracy.

The mount runs on 12 V DC at about 3 A and accepts an external battery pack. The controller connects to a computer by USB, so you can update firmware and load planetarium software for object lists. Set up on a level, firm surface, because the tripod must stay still while the mount slews. Allow the mount to settle after each slew before you focus or start an exposure.

About this configuration

This listing covers one configuration of the Northmere Crag 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. The fitted weather cover keeps dew and dust off the mount if you leave it set up between sessions.

Titanium gray anodizing shows dust less than black and keeps a uniform look over the years. This is the 2024 edition, which revised the altitude adjustment and the cable routing of the Crag line. For steady views, keep the total load of tube, finder, and camera below the rated payload with some margin to spare.

What's in the box

• GoTo alt-az mount head
• Handheld GoTo controller
• Universal dovetail saddle with two clamps
• USB cable
• 12 V DC power cable
• Hard carry case
• Fitted weather cover

Compatibility notes

• Accepts dovetail bars up to 76 mm (3 in) wide.
• Mounts to standard 3/8-16 tripod heads or a pier adapter.
• Suits refractors up to about 150 mm aperture and 10 kg for steady views.
• Controller updates over USB and works with planetarium software for object selection.