Corvane Ember 76 reflector, tube with equatorial mount

Specifications

Description

The Ember 76 is a Newtonian reflector built around a 76 mm parabolic primary mirror. Its 600 mm focal length gives a focal ratio of f/7.9, which keeps the field of view wide at low power and still supports useful magnifications on the Moon and the brighter planets. Because the optics are mirrors rather than lenses, the tube shows no chromatic aberration, so bright objects such as Jupiter and Venus appear without the color fringe that small refractors can show.

The primary mirror is aluminized and overcoated for reflectance across the visible spectrum. A flat secondary mirror, held on a four-vane spider, sends the light to the side of the open tube, where the focuser is mounted. The central obstruction and spider vanes reduce contrast slightly compared with an unobstructed refractor of the same aperture. The open tube reaches outdoor temperature quickly, so you can start observing soon after setup. Check the collimation after transport, because a misaligned secondary reduces sharpness across the field.

The 1.25 in rack-and-pinion focuser accepts standard 1.25 in eyepieces and takes a star diagonal for overhead viewing. The tube weighs 2.1 kg and fits on a light alt-az mount or a tabletop base, so you can carry the complete setup in one trip. The 6x30 finder helps you locate objects before you switch to the eyepiece. A 25 mm eyepiece with this focal length gives about 24x magnification, a practical starting power for wide-field views.

Typical targets include the Moon's craters and terminator, the bands and four Galilean moons of Jupiter, and the rings of Saturn when the planet is well placed. At low power the tube frames the Double Cluster in Perseus and the Orion Nebula. Under dark skies, the core of the Andromeda Galaxy and the brighter globular clusters appear as faint, soft patches, and their detail improves with larger apertures.

About this configuration

The Corvane Ember 76 reflector is offered in several configurations, and the notes below describe what this particular combination adds or changes. The equatorial mount follows the sky along one axis once you align its polar axis with the celestial pole. Balancing the tube and the counterweight before each session helps the equatorial mount move smoothly in both axes. 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 2023 edition uses the same optical design as later years, with small differences in fittings and labels. The optical figures in the specifications table apply to this configuration and to every other version of the Corvane Ember 76 reflector.

What's in the box

• Optical tube with front and rear dust caps
• 6x30 finder scope with bracket
• 1.25 in 25 mm eyepiece
• Tube rings with dovetail bar
• Collimation cap
• Equatorial mount with steel tripod
• Counterweight and counterweight shaft
• 6 mm planetary eyepiece (1.25 in)
• Four color filters (1.25 in)

Compatibility notes

• Accepts 1.25 in eyepieces and filters directly in the focuser.
• The dovetail bar fits light alt-az and tabletop mounts with a standard saddle.