Halden Ridgeline 114 Dobsonian, with Dobsonian base

Specifications

Description

The Ridgeline 114 Dobsonian is a Newtonian reflector mounted on a simple altazimuth base. Its 114 mm parabolic primary mirror gathers light for a focal length of 912 mm, which gives a stated focal ratio of f/8. At that ratio, coma is small at moderate powers, and the eyepiece stays at a workable height when the tube points near the zenith.

The optical tube carries a 31 mm minor-axis secondary mirror on a four-vane spider, which leaves a central obstruction of about 27 percent of the aperture. The primary mirror sits in a cell with three collimation screws, and the tube weighs 4.6 kg with the focuser and finder in place. A 2 in dual-speed rack-and-pinion focuser carries a star diagonal and a heavy eyepiece without slipping.

The Dobsonian base uses a plywood rocker box with a PTFE-on-laminate bearing surface, so the tube moves smoothly in altitude and azimuth without a drive. Assembly takes about thirty minutes, and the rocker box comes in two pieces for storage. Because the mount is manual, you will need to nudge the tube to follow the sky, and the 6x30 finder helps you locate targets before you move to the eyepiece.

Typical targets include the Moon, where the terminator shows craters and mountain ranges at high power; Jupiter, with its equatorial belts and the four Galilean moons; Saturn, with its rings at moderate power; and the Double Cluster in Perseus, which fits in one field with a 2 in eyepiece. Under dark skies, the tube also shows the brighter globular clusters such as M13 and the Orion Nebula, although the nebula will show more structure with a larger aperture.

About this configuration

The Halden Ridgeline 114 Dobsonian is offered in several configurations, and the notes below describe what this particular combination adds or changes. The Dobsonian rocker base keeps the telescope low and stable, and you aim it by pushing the tube gently by hand. The base and the tube separate for transport, which makes the telescope easier to carry out of the house in two trips. The carbon fiber tube expands less as the temperature drops, so the focus point drifts less as the night cools.

The planetary kit adds a short focal length eyepiece and a set of color filters for the Moon and the bright planets. The optics in the 2024 edition match the other years; the changes concern hardware details only. The optical figures in the specifications table apply to this configuration and to every other version of the Halden Ridgeline 114 Dobsonian.

What's in the box

• Optical tube with 31 mm secondary mirror and four-vane spider
• Dobsonian rocker box in two pieces
• 6x30 finder scope with bracket
• 2 in dual-speed focuser with 1.25 in eyepiece adapter
• Collimation tool
• Front and rear dust caps
• Dobsonian rocker base with altitude bearings
• 6 mm planetary eyepiece (1.25 in)
• Four color filters (1.25 in)

Compatibility notes

• Accepts 2 in eyepieces directly and 1.25 in eyepieces through the supplied adapter.
• The rocker box is sized for this optical tube and does not fit other Halden tubes.
• The finder bracket fits the supplied 6x30 finder only.