Northmere Fathom EQ mount, with steel tripod

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. The steel tripod gives a heavy, stable base that damps vibration quickly after you touch the focuser. A steel tripod adds weight to carry, but it settles fast when the wind picks up during a session. No add-on is included, which suits observers who already carry their own cases, bars, and power supplies.

Anodized red parts have the same corrosion resistance as the black finish, in a brighter color. The 2023 edition uses the same gears and bearings as later years, with small differences in the clamps. 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

• Equatorial mount head with dual dovetail saddle
• Counterweight shaft
• Two slow-motion control cables
• Polar alignment scope bracket
• Accessory tray
• Steel tripod with accessory tray

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.