Northmere Fathom EQ mount, head only

Specifications

Description

The Fathom is a manual German equatorial mount for heavy refractors, long-tube reflectors, and imaging setups with a combined load up to 22 kg. Its polar axis is supported by two sealed bearings, one at each end, which keeps the axis rigid under the leverage of a long optical tube. The right ascension and declination axes carry counterweights, so the telescope stays balanced as you move it across the sky.

Fine adjustment is handled by slow-motion cables on each axis, which let you center a target in the eyepiece without touching the optical tube. Tension knobs on both axes set how freely the head moves. A polar alignment scope fits the rear of the polar axis housing, so you can align the mount to the celestial pole with the telescope in place. Once aligned, the mount keeps a target near the field center for longer than an alt-az mount can, which matters at high magnification.

The mount has no motors in its base configuration. An optional right ascension drive kit attaches to the RA axis and runs from 12 V DC, using a separate battery pack or regulated supply. Without the drive, you follow the sky by turning the slow-motion control, which suits short visual sessions and planetary observing at moderate power. The head weighs 14.5 kg, so transport is easier in two parts, with the head and counterweight shaft carried separately from the tripod.

Set up the tripod on level ground, extend the legs fully, and tighten the leg locks before attaching the head. Keep the total load, including the telescope, diagonal, eyepiece, and finder, below the rated 22 kg payload. Heavy loads at the far end of a long tube increase settling time after focusing, so allow a few minutes before observing.

About this configuration

Each configuration of the Northmere Fathom EQ 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. A spare dovetail bar lets you keep a second telescope ready to swap onto the mount in a minute.

A white mount head is easy to see in the dark, which helps you avoid walking into the tripod. The 2025 edition keeps the same payload rating and gearing as the earlier years of the Fathom line. The payload rating in the specifications applies to the mount head in every configuration of the Fathom line.

What's in the box

• Equatorial mount head with dual dovetail saddle
• Counterweight shaft
• Two slow-motion control cables
• Polar alignment scope bracket
• Accessory tray
• Spare 200 mm dovetail bar

Compatibility notes

• Accepts dovetail bars up to 50 mm wide.
• The 3/8-16 base thread fits most heavy-duty photo tripods; a 1/4-20 adapter is included.
• Suits a combined telescope and accessory load up to 22 kg.
• The optional right ascension drive kit requires a 12 V DC supply and is sold separately.