Northmere Fathom EQ mount, with steel pier

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

The Northmere Fathom EQ mount is sold in several configurations, and the notes below describe what this particular one includes. The steel pier raises the mount and leaves more room under the telescope for long refractors and cameras. A pier lets the telescope swing past the meridian without the tube or the camera hitting the legs. A spare dovetail bar lets you keep a second telescope ready to swap onto the mount in a minute.

The anodized red finish makes the clamps and knobs easier to find by touch and by red light. This is the 2023 edition of the Fathom line, the earliest version that is still listed in the catalog. 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
• Steel pier with leveling base
• 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.