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Roscoe
07-10-2010, 06:30 PM
Looking at buying this what you think?


254mm Dobsonian Synscan
[SWSYNSCAN-DO]$1,595.00 $1,369.00http://118.127.11.230/catalog/images/pixel_trans.gifhttp://118.127.11.230/catalog/images/Sky-watcher-Dob8Synscan.jpg
Click to enlarge (javascript:popupWindow('http://118.127.11.230/catalog/popup_image.php?pID=557&osCsid=fc202b903a07f8007237f8e83dbb f94a')) ***INTRODUCTORY PRICE***

A COLLAPSIBLE TRUSS-TUBE DOBSONIAN DESIGN WITH SYNSCAN GOTO --THE ULTIMATE CONVENIENCE!

The Sky-Watcher Go-To Dobsonian Series combines the convenience and affordability of the traditional Dobsonian with the convenience of a computerized Go-To telescope.
The exciting new Sky-Watcher Go-To Dobsonian series is precision engineered instrument that will allow you to easily find and enjoy viewing night sky treasures, such as Planets, Nebulae, Star Clusters, Galaxies and much more. With its patented collapsible tube design, these Dobsonians are truly the ultimate in portability and performance.
The SynScanTM AZ hand control allows you point your telescope at a specific object, or even tour the night sky at the touch of a button!! The user-friendly menu system allows automatic slewing to over 42,900+ objects. Even an inexperienced astronomer can master its variety of features in a few observing sessions. The patented dual encoder design allows the telescope to be moved manually whenever the user wishes - but with no need for re-alignment!
This elegant truss tube design was carefully engineered to combine ease of use, extreme portability and consistent performance in an affordable package. Unlike other truss tube designs, the SkyWatcher Collapsible Dobsonian does not need to be disassembled between uses. It transports as two compact pieces that can be assembled and ready to use in just seconds! It is easy to collimate once set up, and it holds its collimation throughout the evening!
The bearing system has been redesigned as well. The new SkyWatcher Collapsible Dobsonians feature smooth azimuth bearings. Even the twelve-inch model can be rotated with just the push of a finger. Like our traditional Dobsonians, the new Collapsible Dobsonians feature SkyWatcher’s patented tension adjustment control on the altitude bearings. This eliminates the need and added cost of clumsy counterweight systems to balance the telescope.

Specifications OTA

Mirror Material: Pyrex
Optical Design:Newtonian (Parabolic)
Diameter: 254mm
Focal Length: 1200mm
Secondary Mirror Diameter: 58mm
F/ratio: F/5
Highest Practical Power: 500x
Faintest Steller Magnitude: 13.9
Resoving Power: 0.5
Finderscope: 8X50 finderscope (may vary)
Focuser diameter: 53mm
Eyepiece(s): 1.25” Super Plossl 25mm and 10mm
Mount Type: Dobsonian
Ground Board Weight(s): 20Kgs
Tube Weight: 18Kgs
Specifications SynscanTM

Power Supply: 10 to 15 V DC 1Amp, 2.1mm Plug (Center positive)
Motor type: DC Servo Motors
Resolution: Motor encoder: 1,620,000 counts per revolution, Main axis encoder: 11,748 counts per revolution
Slew speeds: 1.0X, 2.0X, 8X, 16X, 32X, 200X, 400X, 600X, 800X, 1000X
Tracking Rates: Sidereal, Lunar, Solar
Tracking Mode: Dual Axes Tracking
Alignment Method: Brightest-Star Alignment, Two-Star Alignment
Database: 25 user defined objects. Complete M, NGC and IC catalog, partial SAO catalogues, total 42,900 objects
Go-To Pointing Accuracy: Up to 5 arc min

noswonky
07-10-2010, 07:59 PM
I have the 12 inch (300mm) auto-tracking version of this scope. The only difference is that mine has a different (non-goto) hand controller.

I think you will find it to be an excellent first scope. It is well made and gives good views.

There is an issue which seems to be common to the motorized skywatcher dobs where the azimuth axis has some looseness or 'play'. This means that when you push it, it moves a couple of degrees very easily (too easily) before the bearing starts to provide resistance. This makes it difficult to aim accurately by pushing it manually and difficult to track objects manually.

However, I find that if I only use the motors to do fine adjustments then it's not an issue. It should be even less of an issue with the goto version.