Deep Sky Tracking: The WiFi-Enabled Star Adventurer 2i Tracker

 

The Star Adventurer can be attached to any camera tripod. Here the equatorial wedge has replaced the tripod head.

All images by Alan Dyer.

Sky-Watcher has updated their popular Star Adventurer tracker, adding Wi-Fi programming and enhanced time-lapse functions.

Plus: Time-lapse functions now possible; various modes easy to select
Minus: No speed ramping on time-lapses; separate polar scope illuminator

Summary: The Wi-Fi programming expands the new Star Adventurer 2i beyond a basic tracker into a capable motion controller for time-lapses.

Who Is It For? Nightscape photographers and all deep sky photographers

Since its introduction in 2014, the Star Adventurer has been one of the most popular of several low-cost star trackers now available from various manufacturers. I tested the original model for our Canadian SkyNews magazine (Nov./Dec. 2014) and was impressed with its tracking ability.

But while the original Star Adventurer also promised time-lapse functions, it offered only limited “hard-wired” settings of little value in most situations. An obscure “Advanced Firmware Update” did add more flexible time-lapse functions, but programming the complex parameters through button presses was crude.

In 2017 Sky-Watcher introduced the Star Adventurer Mini, or SAM, a smaller tracker with lower load handling, but with Wi-Fi allowing it to be programmed easily via the free SAM Console app (Android or iOS). The Mini can perform time-lapses that are fully adjustable with the user’s choice of exposure time, frame count, interval, swing angle — all the factors that make up a motion-control timelapse where the camera pans across a scene during the sequence.

The new 2i version of the bigger Star Adventurer adds all those functions of the Mini, and more, countering the shortfall of the original model. I tested a unit purchased from random stock from my local telescope dealer here in Alberta.

Adding a ball head adapter (not included) is the simplest setup for wide-angle to short telephoto lenses. For time-lapses, the Star Adventurer can be tipped to 90° latitude on the wedge to pan parallel to the horizon.

Basic Sky Tracking

Most buyers will be interested in the 2i foremost for its ability to track the sky allowing long, untrailed exposures of the Milky Way or constellations, either with a landscape in the foreground or when framing just starfields.

Out of the box, the 2i is programmed to turn continuously and to fire a camera shutter for an unending series of 2-minute exposures, provided you have the camera’s remote port connected to the 2i’s Snap port via an optional intervalometer cable, and the camera set on Bulb.

However, you can use the Console app to program in a specific number of exposures of any length you choose, then save that combination as a named “Profile” or preset. You can have many presets for quick recall.

Once a sequence is started, it loads into the memory and, if you have AutoRun Task turned on under Settings, the Star Adventurer will run that preset by default the next time you start it up in Astrophotography mode. So unless you want to change the settings, there is no need to go into the Wi-Fi app each night.

Indeed, there is no need to use the Snap port at all; you can use a separate intervalometer to run the camera, making it easier to change shutter speeds through the night as needed. But if the Star Adventurer is programmed to fire only a set number of frames it will stop turning after that sequence is done. Just turn it off and back on to start it tracking again.

Tracking Accuracy

The tracking proved quite accurate. In a series of unguided 2-minute exposures using the William Optics RedCat astrograph (with its focal length of 250mm), about half the frames were untrailed enough to be usable, a very good “take” for a small tracker shooting at that focal length. When shooting with a shorter 85mm to 135mm telephoto the ratio would be even better.

The RedCat is about the longest focal length and, at 3.5 kg with guider and camera, the heaviest optics I would recommend on the 2i (it’s rated to handle 5 kg).
To improve tracking, the 2i offers a standard ST-4-compatible autoguider port. Using the ZWO ASIAIR Pro and ASI guide camera setup shown here, all the 2-minute exposures in a test set of two dozen were well tracked with no trailing in right ascension (east-west).

The author used a RedCat astrograph (left) to capture 18 two-minute autoguided exposures of M31 that were then stacked. The autoguiding graph (right) shows that guiding accuracy is adequate for short focal length optics.

No autoguiding is possible in declination (north-south). Thus, trailing in declination will still result if polar alignment is off. However, I found the 2i’s built-in polar scope sufficient for a polar alignment good enough for short telephotos and small astrographs like the RedCat.

The continued annoyance with the 2i is that its polar scope is still not internally illuminated and the separate little illuminator is easily lost or forgotten. Also, the electric slow motions in the east-west direction are still too slow to be of much use for framing shorter focal length lenses.

However, the declination bracket that comes with the Astro and Pro Pack bundles does have a precise manual slow-motion control for ease of aiming and framing in the north-south direction. It’s an essential feature for deep sky imaging with telephotos and telescopes that is missing on the competition (iOptron SkyGuider Pro review by Alan Dyer).

If you are shooting nightscapes and the Milky Way just with wide-angle lenses, the expense and fuss of autoguiding will not be necessary, though accurately polar aligning is still a good habit. To that end, the SAM Console app provides a display showing where to place Polaris on the polar scope’s reticle for the Northern Hemisphere, or where to place the U-shaped pattern of faint stars near Sigma Octantis for the Southern Hemisphere.

Time-Lapse Functions

What sets the Star Adventurer 2i apart from most other trackers is its ability to also function as a time-lapse motion controller.

In this mode you do not polar align, but aim the polar axis straight up. The camera must be connected to the Snap port, as the shutter has to be synchronized with the motion. Instead of turning continuously, the 2i instead turns by a tiny increment between each exposure, in what is called a Shoot-Move-Shoot mode.

You program in the angular extent of the move and the number of frames desired and, in the Long-Exposure Time-Lapse mode, the shutter speed. A Regular-Exposure Time-Lapse mode is for daytime uses where the 2i sends just a short pulse to the camera to trigger the shutter, with the exposure set by the camera.

The time-lapse modes work very well, but like all motion controllers take some skill in getting the settings right so the moves don’t end up either dizzying or failing to move enough for a good effect. Settings that will move the camera by 15 degrees (°) per hour (such as a 45° move over 3 hours) will nicely follow the Milky Way as it travels along the horizon. Again, the app allows saving user presets for easy recall.

Also, the last sequence run in each mode gets assigned to the control dial’s various positions. So as long as you wish to run that particular sequence again, you need only turn the dial to, say, the Long-Exposure position (or one of the others) and away it goes, with no need to go into the Wi-Fi app. That’s a convenient feature missing from the Mini, which can auto-run only one sequence.

A deficiency of both the 2i and Mini is that neither offer a speed ramping option where the device eases into a time-lapse move, then out of it at the end of a sequence. Speed ramping produces a final movie that smoothly speeds up, pans across a scene, then gradually slows to a stop, for a more polished appearance. Instead, the 2i and Mini start turning at full speed with the first shots and just stop abruptly with the final frame.

Dedicated time-lapse motion controllers such as the SYRP Genie Mini2  or Alpine Lab’s Radian2 offer speed ramping, but do not have star tracking functions.

Unique Astro Time-Lapse

A function that is unique to both the new 2i and the older Mini is their Astro Time-Lapse mode. In this mode you do polar align, then frame a nightscape scene. The Star Adventurers will then track the sky for the programmed length of each exposure, preventing star trailing and recording a richer Milky Way.

After each exposure the Star Adventurer (2i or Mini) resets its position back to where it started, then resumes tracking, firing the shutter again. This also worked very well, showing absolutely no frame-to-frame jitter from imprecise re-framing.

Examples of test time-lapses made with the StarAdventurer 2i from Vimeo.

In all, the new Star Adventurer 2i is a major improvement over the original model in providing many more shooting options through its Wi-Fi app.

However, if your interest is taking just tracked night sky images, and not time-lapses, and you already own an older Star Adventurer, upgrading to the 2i won’t provide any significant benefit.  But if you are buying your first tracker, the new 2i is well worth considering for its wide range of shooting modes, including time-lapse options, and excellent tracking accuracy. I suggest getting the full Pro Pack to have all the accessories.

Sky-Watcher Star Adventurer 2i Tracker is available from Sky-Watcher dealers worldwide.

MSRP: $339 for Photo Pack bundle with just the ball-head adapter
$349 for Astro Pack bundle with ball head adapter and declination bracket
$419 for Pro Pack with all accessories incl. equatorial wedge and counterweight

Website: https://www.skywatcherusa.com/

About Alan Dyer

Alan Dyer is an astrophotographer and astronomy author based in Alberta, Canada. His website at www.amazingsky.com has galleries of his images, plus links to his product review blog posts, video tutorials, and ebooks on astrophotography.

Related posts