The Polarie Star Tracker is a tripod mounted gadget that provides a battery powered rotating camera platform, allowing you to take longer exposure photographs of stars without trails.
Vixen Polarie Star Tracker Features
The Polarie Star Tracker is a chunky brick-like gadget with a creamy white colour that looks like a point & shoot compact camera. It's about the same size as one of the early film compacts or a typical modern digital SLR body, but when you pick it up you soon realise with the weight that this has some heavy duty guts.
Inside is a motor driven rotational device that, via the external camera mounting block, turns the camera at the same speed and direction as the diurnal motion of stars. Aligned correctly to the Polaris and the Star Tracker will allow you to take photos of stars without any trails. This is ideal when shooting longer exposures to record constellations and the Milky Way.
It's powered by two AA batteries and has a USB socket to allow a external 5V DC power supply to be connected. There is a silver circular plate on front and rear. The front one is the removable camera mounting block and the rear is a screw-in compass. On top is an accessory shoe and an illuminating mode dial.
The dial has a series of modes with icons that illuminate when set. A clever twist is they illuminate red if you have tracking set to N (northern hemisphere) or green if tracking is set to S (southern hemisphere).
Preparation where you use the tilt meter to adjust the angle of the Star Tracker on the tripod to the latitude of your shooting location.
Star-scape photography which tracks at half the speed of the celestial tracking rate for shots with star and landscape objects (trees, buildings etc).
Wide-field Astrophotography works at the celestial tracking rate for shooting constellations and milky way with no surface objects which might record as a blur.
Solar tracking to take photographs of the sun.
Lunar tracking to take photographs of the moon.
Other features include a small viewfinder (polar sight hole), a tilt meter and a 1/4 tripod thread.
Vixen Polarie Star Tracker Handling
The Star Tracker feels really robust due to the internal weight. First thing to do is insert batteries and mount the box onto a tripod. The battery compartment cover is surprisingly flimsy considering the robustness everywhere else. It's light plastic with clips that feel like they will break easily. The tripod bush is standard 1/4in and is metal, so wont be a problem with what you're about to balance on the end of it.
Next you need to attach the second ball head to the Star Tracker's camera mounting plate. This has two thumb screws to unlock and release. There's a small spring button in the centre that pushes the 1/4in thread out so the head can be screwed on. Many tripod heads have a larger 3/8 thread connector so you may also need a 3/8 to 1/4 adaptor. Once the head is attached, the plate can be returned and locked back on the Star Tracker. The metal to metal is very reassuring and when locked in place feels solid and safe.
The specifications state that the maximum load is 2kg which does narrow down what you can put on the Star Tracker. The heaviest kit I attached was a Vanguard Ball & Socket and Pentax K20D with 12-24mm wide angle with a total weight of 1.77kg.
If you use a pro spec Nikon or Canon with equally pro wide zoom you could easily be pushing on for 3kg. So you may have to consider using a different fixed focal length lens if that's the only camera in your outfit.
With everything in place you need to do the polar alignment using the compass to find North and the tilt meter to set the latitude. My location is approx 50 degrees latitude so that was set accordingly.
The tile meter illuminates red but isn't that clear to view in low light.
Then look through the polar site hole (it's just a hole, no optics) and locate the Polaris (North Star) making adjustments with the pan head on the tripod so the star is central though the hole.
If you're unfamiliar with the Polaris, the manual has a star position guide. There's plenty of helpful guides on the internet too.
The closer the star is to the middle the more accurate your alignment wil be. Those who want extreme accuracy may find the optional Polarie Polar Axis Scope will come in useful. This slides into the centre hole and has an 6x magnification with a precise target position to align the star. It's a lovely bright 8x20 scope but I found I couldn't see the target markings in the dark so they need to illuminate to be of any use.
Once the Polarie is aligned you can adjust camera position so that the stars or constellation you want to photograph can be seen through the viewfinder. Then set the exposure time - the manual comes with a table showing how long an exposure duration can be set for the focal length of lens and separation from celestial equator. For star scape photography the range is between 2sec and 105sec, while in the wide field mode you can achieve a maximum of anything from 1min to 39min. The Solar and lunar trackers can maintain constant tracking for up to four hours.
Vixen Polarie Star Tracker Performance
Typically we haven't had a clear sky here for weeks, so I've not been able to take as many photographs as I'd hoped in the test period. I did, however, have enough time to get a good idea of performance. And it works well. It's easier to set up than I imagined when first viewing the unit with the instruction book to hand. Astronomy isn't something I'm familiar with so Polaris and diurnal motion were new words. That said within minutes I'd set up and was taking my first photo. I used the polar sight hole for alignment and although not as accurate as I could have ben with the Polar scope the results are quite impressive. I switched over from the Pentax K20D ot the Olympus OM-D EM-5 as I prefer to work in LiveTime mode where I can see when the correct exposure has been achieved.
Here's a shot taken with the Olympus OM-D EM-5 and 14-42mm lens set at 14mm. The Plough is to the right. ISO200 was set which gave an exposure of 60 sec at f/5.6.
The following three show the difference each mode makes. I've included some trees in the shot to show the effect on land based objects.
Polarie turned Off 120 sec | f/11.0 | 14.0 mm | ISO 200. The stars indicate how much movement will be traced at two minute exposures but the trees are sharp.
Polarie set to Wide Field | 121 sec | f/11.0 | 14.0 mm | ISO 200. This mode freezes the stars but the trees are blurred
Polarie set to Star Scape | 121 sec | f/11.0 | 14.0 mm | ISO 200 This mode provides a combination of less movement in both the stars and included landscape.
I'd only been using the unit about an hour when the battery indicator started flashing. The spec says 2 hours at 20 degrees C but I was working at about -2. So you will need several sets of spare batteries if you're taking this out to a remote pollution free location. Or buy and use a USB external battery pack.
Vixen Polarie Star Tracker Verdict
I am hoping the weather will change and we get some clear nights so I can go out to more remote locations with less light pollution and take some cool starscapes. I was able to get to a point where I have no qualms in recommending this box of tricks. The Star Tracker will give those who admire astrophotography a chance to shoot their own stunning starscapes. If I can get this good without any experience those versed in such nocturnal activities will find the gadget really beneficial.
Vixen Polarie Star Tracker Pros
Easy set up and alignment
Accurate tracking mechanism
Range of shooting modes
Vixen Polarie Star Tracker Cons
Flimsy plastic battery cover
Tilt meter not easy to see in dark
VALUE FOR MONEY
Vixen Polarie Polar Axis Scope Specifications
|Box Contents||scope, front and rear caps|
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