Halden Apex 102 ED refractor, tube only

Specifications

Description

The Apex 102 ED is a doublet refractor built around one element of extra-low-dispersion glass. With 102 mm of aperture and 714 mm of focal length, it works at f/7, a ratio that gives a fairly wide field at low power while still taking high magnification on the Moon and the planets.

The ED element brings blue and red light to nearly the same focus as green light. In practice, bright objects such as Jupiter, Venus, and the lunar limb show only a faint color fringe, much less than an achromat of the same size and focal ratio would show. The lens is fully multi-coated and sits in a tube with several knife-edge baffles, which keeps the background dark when a bright planet sits near the edge of the field.

The 2 in dual-speed rack-and-pinion focuser carries a star diagonal and a heavy eyepiece without slipping, and the fine-focus knob gives a 10:1 reduction for planetary detail. A retractable dew shield slows dew on the objective and blocks stray light from nearby windows and streetlights.

At 3.6 kg for the tube, the Apex 102 ED rides on a light alt-az mount or a small equatorial mount, and it fits in a carry-on sized case for travel. Like other small refractors, it reaches the outdoor temperature sooner than a reflector or a catadioptric of similar size, so you can start observing soon after you carry it out.

Typical targets include double stars such as Albireo and Epsilon Lyrae, the phases of Venus, the rings of Saturn, and bright open clusters such as the Double Cluster in Perseus, which fits in one field with a 2 in wide-field eyepiece. Under dark skies the tube also shows the brighter galaxies and globular clusters, although larger apertures reveal more of their structure.

About this configuration

This listing covers one specific configuration of the Halden Apex 102 ED refractor, defined by its bundle, finish, accessory kit, and edition year. This is the optical tube on its own, so you need to supply a mount that can carry its weight steadily. Buying the tube alone makes sense if you already own a suitable mount or plan to choose one separately. The matte black finish hides scuffs and keeps reflections from porch lights and streetlights to a minimum.

With the starter kit, begin with the low-power eyepiece whenever you search for a new target, then switch up. The 2025 edition keeps the same optical figures as the earlier years of the Apex line. The optical figures in the specifications table apply to this configuration and to every other version of the Halden Apex 102 ED refractor.

What's in the box

• Optical tube with retractable dew shield
• Tube rings with Vixen-style dovetail bar
• 2 in star diagonal with 1.25 in adapter
• Red-dot finder
• Front and rear dust caps
• 25 mm and 10 mm eyepieces (1.25 in)
• 2x Barlow lens (1.25 in)

Compatibility notes

• Accepts 2 in eyepieces directly and 1.25 in eyepieces through the supplied adapter.
• The Vixen-style dovetail bar fits most small and medium mounts.
• The focuser has a T2 thread for camera adapters once you remove the 2 in nosepiece.