Tele Vue 2.5x Powermate - 1.25"

The Powermate Concept: A 4-Element Pupillary-Correcting Amplifier

While a conventional Barlow lens uses a negative lens system to diverge light rays, the Tele Vue Powermate uses a more advanced 4-element design. This system combines a negative achromatic doublet with a positive "pupil-correcting" doublet. While it looks and functions like a Barlow, your eyepiece will operate with pupil locations where the designer intended, avoiding the mismatched pupils that cause vignetting and image degradation in short, high-power Barlows.

No additional "interface lens" is needed, since Powermates have it built in. Tele Vue adds full multi-coating, captive lock screws that can't fall out, and a 100% QC program at f/4.

A 2.5x Factor for High-Resolution Visual Observing

Choose a long focal length eyepiece with comfortable eye relief and use image amplifiers to increase power, as Barlows retain eye relief. Aim for at least 150x for planets and double stars, and treat about 300x as the usual atmospheric limit.

Tele Vue's example: with a 22mm Panoptic you have the power of an 8.8mm eyepiece, 136x in a 1200mm telescope.

Barrel, Filters and Focus

The 2.5x and 5x Powermates are threaded for 1¼" filters (M28.5 x 0.6 in the spec table). The maximum barrel diameter is 1.6" (41 mm).

• Captive Lock Screws: Tele Vue fits lock screws that can't fall out.
• Parfocal Design: Both 1¼" Powermates are parfocal with the Tele Vue 1¼" 90° diagonal, often used in smaller telescopes.
• Safety Undercut: The chrome barrel has a safety undercut where practical; note that the 2x and 2.5x Powermates do not insert fully on certain diagonals.

Dobsonian/Newtonian Use: Pairing the 2.5x Powermate with Paracorr

The Powermate works with Tele Vue's Paracorr coma corrector in Newtonians and Dobsonians.

To use the 1.25" 2.5x Powermate with a Paracorr, you simply insert the Powermate into the Paracorr's 2"-to-1.25" adapter. Set the Paracorr's Tunable Top at its highest position.

Planetary Imaging: Attaching a Camera for 2.5x Amplification

Powermates are ideal alternatives to "eyepiece projection" for photography and CCD imaging.

To connect a DSLR or dedicated astronomy camera, the bottom portion of the Powermate's black barrel unscrews. This section then threads directly onto the Tele Vue Powermate 1.25" T-Ring adapter (model PTR-1250, sold separately). Then screw it into your camera's T-ring adapter.

Quality Control and Warranty

A 100% QC program at f/4 ensures the Powermate will add dramatic power "(and NOTHING ELSE)" to your eyepieces.

Tele Vue gives Powermates a Lifetime Limited warranty against defects in material or workmanship.

The 2.5x Powermate vs. the 2x, 4x, and 5x Models

Tele Vue makes Powermates in 1¼" (2.5x and 5x) and 2" (2x and 4x). With a 22mm Panoptic they give 11mm, 8.8mm, 5.5mm and 4.4mm.

• vs. 2x Powermate (2"): Takes 2" eyepieces (1¼" with its adapter) and weighs 1.20 lbs.
• vs. 4x Powermate (2"): A 2" model with brass clamp ring; 4x on a 22mm eyepiece gives 5.5mm.
• vs. 5x Powermate (1.25"): Also 1¼" and threaded for 1¼" filters, at twice the power; it suits shorter telescopes.