Equipment Review

Vixen Optics "Polarie"

Product Code: 35505

Purchase price: JPY 35,000 (outlet)

Please appreciate that this review reflects personal impressions and views.

The Earth completes one full rotation in 23 hours 56 minutes and 4.0905 seconds. This period is referred to as a Sidereal Day. As a result of Earth's spinning, stars draw an arc on long exposure photos. Vixen's Polarie was developed to compensate for the apparent motion of the stars. This technique is known as "tracking". A tracked exposure can minimize star trails, smearing and egg-shaped stars. Fitting in any suitcase, the Polarie is designed for grab and go into the field without regrets.

The Vixen "Polarie" is a Mobile Tracker, compact and robust in camera look and feel designed for guiding wide field nightscape and constellation exposures. It sports a stepper motor and electronics powered by two AA batteries or through its USB power input port. The 'engine' of the Polarie is as finely developed and crafted as the outer casing.

The Polarie has a 8.9° wide round sighting hole to assist polar alignment to either celestial pole. This is the most critical issue as tracking accuracy is as good or as poor as the alignment which is often a try and error game. However, once really well aligned, Polarie can track up to three minutes efficiently avoiding notable star trails.

It is mechanically and physically extremely difficult to realize, let alone, to guarantee, but some more payload weight would be nice to have for heavy camera gear. Not all DSLR's are as light as, say, the Nikon D5300. Users will certainly also wish to challenge tele lenses up to 300mm. Due to the unavoidable physical limitation, the payload does not affect the overall rating.

The minimum working configuration includes Polarie, a sturdy tripod and a ballhead. It is also sold as a kit including all these. Usable in both northern and southern hemispheres, the Polarie has four tracking modes that can be found in big equatorial mounts:

Celestial rate
1/2 of celestial rate
Solar tracking
Lunar tracking

The tracker and optional accessories appear overpriced, but one must consider that the products are not manufactured in millions of units. And - it is Made in Japan. Vixen's production quality deserves a top grade.

Orion: single frame, 30 seconds, ISO 800 with Polarie. Full Screen

Positive

Robustly crafted, 740gr (1.4lbs) light-weight.
Small, portable, battery powered.
Long battery life. *
No plastic parts in critical places.
Motor and gear wheels made of wear-resistent brass.
High-quality protective body varnish.
Up to 3kg (6.6lbs) maximum allowable payload.
Four selectable tracking (speed) modes.

Source: Vixen Optics
Do not dismantle the screw-less unit yourself!

Negative

Thin battery compartment plastic cover.
No crosshairs in the alignment sighthole.
Polar alignment awkward without optional parts.

* About 2 hours at 20°C (68°F), a 2kg load using Alkaline batteries.

Porta II as Polarie Mount

The Alt-Az head of Vixen's Porta II mount provides numerous threads for attaching optional parts or home-brewed gear. The Porta II is not only smooth in its slow motion control but also sturdier than a conventional photo tripod. The photo above shows just one low-cost, simple means of attaching the Polarie to a Porta II mount. If you do not need to quickly swap gears you can attach the Polarie without the dovetail plate holder as shown by the photo inset. Less parts, less play.

First Field Test

Star field images containing M31 at the upper right side taken without and with "Polarie" using the same 28mm f2.8 lens, 30 seconds exposures at ISO 400. The result does not require an explanation, except: "not bad at all"!

The slices from JPEG images are right out of the camera. The enlarged full FOV views (on click) showing Cassiopeia on the left side are processed with an unsharp mask. With a bit more 'polar alignment luck' the right image could show perfectly round stars.

With Zoom Lens

Single frames, both 20 seconds at ISO 1600, unprocessed out of the camera. Nikon D5300 with 135mm F1:2.8 lens. Diffraction of bright stars generated with a Kenko R-Cross Screen filter.

Stacked Images

Jupiter in Sagittarius is a stack of 13 frames, 30 seconds each at ISO 1600. Nikon D5300 with 28mm F2.8 lens tracked with Polarie on 2019-05-04.

Messier 7 in Sagittarius is a stack of 16 frames, 25 seconds each at ISO1600. Nikon D5300 with 28mm F2.8 lens tracked with Polarie on 2019-06-06.

Polarie with Higher Payloads

Twin Plate

For about 12.00 USD a twin plate, also known as twin camera base, serves a useful purpose. In order not to compromise tracking accuracy, heavy photograpic gear needs to be well balanced. The twin plate has a 1/4" thread that attaches it to the Polarie. A thin tape in between the Polarie and the plate will help avoid slipping and scratches. Each end of the twin plate has a 1/4" screw knob to which a camera ball head can be attached on the one side and a counterweight (or another ball head) on the other. Since the plate is nearly centered on the Polarie the counterweight should ideally be about the same weight, but can be fine-balanced by moving it on a travel of 100mm towards or away from the center of rotation. If well balanced the Polarie can so accept up to 5kg payload, versus its native 2kg capacity (please confirm the load capacity with Vixen). Vixen offers a step-up kit at 600.00 USD which serves the same purpose. The twin plate shown on the photo is from the Japanese manufacturer Etsumi, about 180mm long and 30mm wide, and has a 2mm thick cork layer on one side.

If there only was a counterweight with a 1/4" thread. Please copy this at your own risk.

Polarie as Scope Tracker

The Polarie as-us can manage to 3kg cargo (absolute maximum). The Celestron AstroMaster 80AZS tube weighs about 1.3kg + eyepiece, well within Polarie's specification. Thanks to Polarie a so mounted and well balanced light-weight telescope can be tracked roughly for, say, group observations and star parties. Of course, this is not a sturdy setup. A wind shield and an attendant might be useful.