Sky-Watcher Flextube 200P SynScan

GoTo on a Collapsible Dobsonian

The SynScan AZ hand control can point the telescope at a chosen object or tour the sky at the touch of a button, and the motors track the object once found.

Even an inexperienced astronomer can master the SynScan features in a few observing sessions.

203mm f/5.9 Paraboloidal Optics

The 203mm paraboloidal primary mirror has a 1200mm focal length, giving f/5.9. The highest practical power is 406x.

Sky-Watcher fits its collapsible Dobsonians with a 2" Crayford focuser; a 1.25" eyepiece adapter is included. Turn the focus knobs slowly until the image is sharp; the manual notes that refocusing over time is normal with short focal ratio telescopes before they reach outside temperature, and after changing an eyepiece.

Collapsible Tube: 1115mm to 835mm

skywatcher.com lists the tube at 320 mm in diameter, 835 to 1115 mm long and 11 kg. Unlike other truss designs, Sky-Watcher's collapsible Dobsonian does not need to be disassembled between uses: it transports as two compact pieces, is ready to use in seconds, is easy to collimate once set up and holds collimation throughout the evening.

To extend the tube, loosen the three slider lock screws, pull the top part out until it clicks in place, and tighten the screws without over-tightening.

Freedom Find Dual Encoders and Motors

Sky-Watcher's patented Freedom Find dual-encoder technology lets you move the telescope by hand or electronically in either axis without losing its alignment or position information. Each axis has two encoders, one on the axis shaft and one on the motor shaft (US Patent 7,228,253). After you move to a new object, the telescope begins tracking it.

DC servo motors drive both axes with ten slew speeds from 1x to 1000x, and track at sidereal, lunar or solar rate in dual-axis tracking mode. The motor encoders have 1,620,000 counts per revolution and the main axis encoders 11,748.

SynScan AZ with a 42,900+ Object Database

The SynScan AZ menu slews automatically to over 42,900 objects, including the complete Messier, NGC and IC catalogs and part of the SAO catalog. The USER key gives access to up to 25 user-defined coordinates.

Before GoTo, level the base and align the system on two stars, with the finderscope already aligned to the tube:

• Brightest-Star alignment: recommended if you are new to the sky. Choose one of eight regions of the sky; the hand control lists the stars brighter than magnitude 1.5 there, you center the first manually, and the mount slews to a second star for you to center.
• Two-Star alignment: choose two stars from a list, at least 60 degrees apart in azimuth.

Power and Computer Control

The middle port on the bottom of the hand control is for RS-232 communication with a computer. The manual says the firmware is compatible with the Celestron NexStar 5i/8i and NexStar GPS command protocol, so planetarium software that supports it can drive the mount.

From version 3.0 onward, the SynScan AZ firmware is user upgradable.

Power

The mount needs 10 to 15 V DC at 1 A through a 2.1 mm center-positive plug, into the Power jack on the altitude motor box. A 12V DC car-lighter power cable is included; the battery pack or power supply is sold separately.

To avoid tangling the power cable, the manual suggests placing the battery pack or power tank on the round base, behind the front panel.

Assembly and Setup

The base comes flat-packed: attach the feet to the round base, then the side panels, front panel, handles and motor boxes with the screws, Allen wrenches (2, 4 and 6 mm) and Phillips screwdriver supplied. Then:

1. Level and extend: check the round base with a bubble level, since better leveling gives better tracking. Loosen the three slider lock screws, pull the top part out until it clicks, and tighten them without over-tightening.
2. Mount the tube: remove the dust cap and front cover, lift the tube with both hands at the positions shown, lower its side bearings onto the mounting platforms inside the side boards, and tighten the locking screw.
3. Align the finder: in daylight, center a distant object in the main eyepiece, then adjust the 9x50 straight-through finder to center its crosshairs on it.
4. Connect: plug the hand control and motor cables into the altitude motor box, then connect the 12V DC power supply.

Focuser, Finder and Eyepieces

The 20mm and 12.5mm 1.25-inch eyepieces give 60x and 96x (1200mm divided by the eyepiece focal length). A 9x50 straight-through finderscope and two dust caps are included.

The highest practical power is 406x.

Tube and Base

It transports as two pieces: the tube, retracted to 835mm and 11 kg, and the base, at 33 lb and 30" x 20". Retract the tube, loosen the locking screw and lift the tube off the base.

Solar Safety

Never use the telescope to look directly at the Sun, as permanent eye damage will result. Use a proper solar filter for viewing the Sun.

When observing the Sun, place a dust cap over the finderscope. Never use an eyepiece-type solar filter, and never use the telescope to project sunlight onto another surface: the internal heat build-up will damage the optical elements.