Steve Richards
The power to track stars is in your own hands… literally, with this clockwork device
Equipment expert Our regular Scope Doctor (page 87) this month also reviews a quirky tracking mount that quite literally works like clockwork.
Historically, the drives and gears used to motorise telescope mounts have been known as ‘clock drives’ because the original mechanisms had much in common with early clocks, which used weights and pendulums to keep time. The Omegon MiniTrack LX2 brings this older technology bang up to date by using a clockwork motor to power a compact equatorial tracking mount that can handle a payload up to 2kg and focal lengths up to 100mm.
Until now, similar ultra-portable tracking mounts have used small electric motors and electronic control circuits to accurately rotate the right ascension (RA) axis. The MiniTrack is, therefore, quite a departure from the well-trodden path. This elegant solution means that an ultraportable mount can be taken anywhere without having to rely on any power requirements other than a little bit of wrist action every hour or so to gently wind up the clock mechanism. This is, perhaps, the first truly eco-friendly mount.
Such an unusual piece of equipment demanded our attention, so we were keen to give it a run. Its arrival in the summer months was ideal for some wide-field Milky Way imaging with a camera and lens, which is what this mount is designed for rather than a small telescope.
Ticking all the boxes
The mount weighs in at 464g (774g with the supplied ball-and-socket head installed) and is just 215mm long by 80mm wide at its widest point, making it almost pocketable. The chassis is a single aluminium casting with a black crackle finish and highly polished components. Attached to one end is a quadrant arm with a rubber platform onto which the substantial ball-and-socket head is attached via a -16 bolt.
If you opt to buy the mount-only version of the MiniTrack you can use your own ball-andsocket head and, if necessary, change the mounting bolt to the -20 bolt supplied, using the spanner and adaptor included in the kit. A moulded clip at the top of the chassis holds a small plastic sighting tube to assist in polar alignment.
Assembling the system is very quick indeed. You start by attaching the MiniTrack to your own tripod’s pan-and-tilt head or precision altaz head so
that you can tilt the tracker to polar align it. You then attach the ball-and-socket head to the mounting platform. Finally, you attach the camera and lens to the quick release dovetail bar.
Next up is polar alignment, which you carry out by sighting Polaris through the polar finder tube then locking the tripod’s head firmly in position. This alignment process was a little subjective but for wide-angle imaging it proved to be perfectly adequate. It should be noted, though, that the MiniTrack will only track the night sky in the northern hemisphere.
Once the mount is correctly polar aligned you then attach the camera to the ball-and-socket head using the dovetail clamp, which we easily managed to achieve even in the dark.
To start the imaging session, you turn the large disc at the foot of the mount a maximum of one rotation to wind up the clockwork motor – it’s as simple as that. Once the motor’s running, you can loosen the ball-and-socket head to allow the camera lens to point to the celestial object you want to photograph and, after focussing, image capturing can begin.
We used an external intervalometer attached to our Canon 450D and 28mm wide-angle lens set to capture a continuous set of three-minute exposures with the camera in ‘bulb’ mode. We used our own hot shoe-mounted red dot finder to aim the lens in the general direction of the bright star Sadr (Gamma
(a) Cygni) in Cygnus, and captured images until the motor ran out, which was exactly an hour later.
The resulting star shapes were impressive, showing no sign of trailing even though we were using the maximum exposure length recommended for our camera and lens combination.
We would recommend the MiniTrack to users of any experience level as a simple means of mounting basic imaging equipment for wide-field imaging.