Sky-Watcher Virtuoso GTi 130 Tabletop GoTo Dobsonian

Tabletop GoTo Dobsonian

This compact and easy-to-use table top telescope is ideal for all kinds of observations. It has a 3/8" thread block for tripod mounting.

130mm f/5 Paraboloidal Optics

The 130mm paraboloidal primary mirror has a 650mm focal length, giving f/5, with a 34.5mm secondary mirror. The highest practical power is 260x, and the telescope shows details in Saturn's rings, Jupiter's bands, the Martian polar ice caps, and the phases of Venus and the Moon.

Telescopes need at least 10 to 30 minutes to cool to outside air temperature, longer with a big temperature difference.

SynScan Wi-Fi Control and Freedom Find

Install the free SynScan or SynScan Pro app on a phone, tablet or laptop, switch the mount on and connect to its "SynScan_xxxx" Wi-Fi network (no password by default) within 15 minutes, after which the Wi-Fi turns off to save power. The SynScan app suits entry-level users and SynScan Pro experienced users. A SynScan hand controller can also be plugged into the hand control port.

Auxiliary encoders on both axes let the mount keep track of its position when you unlock the clutches and move it by hand, so you can point it manually at any time without losing alignment; re-lock the clutches to resume GoTo and tracking.

Collapsible Tube, Eyepieces, Finder and Focuser

The tube extends to 25" and retracts to 14.75". The tube weighs 6.5 lb, the assembled base 10.9 lb and the total 17.3 lb.

• Eyepieces: 25mm and 10mm SUPER 1.25-inch, giving 26x and 65x (650mm divided by the eyepiece focal length).
• Red dot finder: a zero-magnification pointing tool powered by a 3-volt lithium battery, with variable brightness and altitude and azimuth adjustment knobs.
• Focuser: 1.25" helical (Sky-Watcher USA). Remove the black plastic end-cap before inserting an eyepiece, and refocus after changing eyepieces.

Setting Up

Loosen the altitude clutch wheel, rotate the saddle until the dovetail groove is horizontal and tighten the clutch. Slide the tube's dovetail bar into the groove and tighten the dovetail locking knob, holding the tube until it is firmly attached. Then, holding the tube, fully loosen the altitude clutch to check the balance, and slide the bar back or forth until the tube balances in altitude.

To align the red dot finder, remove the insulation sheet from its battery cover and turn it on with the brightness control. Center a distant object in the 25mm eyepiece, then, with both eyes open, look through the sight tube and use the adjustment knobs until the red dot overlaps the object.

Power and Camera Control

The mount runs on 8 AA batteries in its battery compartment or on external power: DC 7.5 V to 14 V, at least 750 mA, through a center-positive barrel plug (2.0 mm I.D., 5.5 mm O.D.). A SNAP port connects to a camera's shutter control port so the SynScan hand control can take pictures automatically.

Observing Tips

Choose a site away from city lights, upwind from air pollution and as high as possible, and do not observe immediately after sunset while the Earth is still cooling.

Expose your eyes to nothing but red light for 30 minutes before observing, keep both eyes open, and use averted vision on faint objects.

Collimation

Collimation aligns the mirrors so they deliver properly focused light to the eyepiece. Center a star and move the focuser so it is slightly out of focus: in good seeing, rings symmetrical about the Airy disc mean the optics are aligned.

The secondary mirror is aligned with the three small screws around its central bolt, and the primary with the three adjusting screws at the back, held by three locking screws. The manual describes a collimation cap, a plastic cap with a small central hole that fits the focuser in place of an eyepiece.

Weight

The total assembled weight is 17.3 lb: 6.5 lb for the tube and 10.9 lb for the base.

Solar Safety

Never look at the Sun through the telescope or the finder without a proper solar filter.