My primary imaging instrument is William Optics Zenithstar 105 ED refractor. Objective diameter of the telescope is 105mm and its focal length is 735mm giving an F7 system. With WO 0.8X focal reducer/corrector focal length of the ZS105 ED can be reduced to 588mm for F5.6 work, resulting in wider image field and shorter exposures. Reducer/corrector also flattens the image field of the telescope, but ST-2000XM/ZS105 ED combination has no problem with field curvature even without it.

The telescope is equipped with decent dual speed Crayford focuser suitable for astrophotography use. The focuser is rotateable which enables easier framing of objects on the CCD chip of the imager. The focuser is strong enough to hold my imaging gear. WO ZS105 ED gives overall impression of sturdy and well built instrument.

This is the "business end" of WO ZS105 ED. This telescope is an apochromatic refractor, meaning that the chromatic aberration (CA) of its objective is well corrected. Objective consists of three separate lenses (triplet construction), and one of them is made of exotic ED glass with special dispersion properties which is a key factor for eliminating CA. Objective is fully multicoated for better light transmission.

Objective is protected with retractable dew and glare shield. Since dew can really be a problem in my area (there is a lake nearby), shield alone is sometimes not enough to prevent dew forming on the objective. That is why I have to use dew heater as well.



Update May 2008:

I've replaced the stock focuser on WO ZS105 ED with MoonLite 2.5" CFL focuser equipped with high resolution stepper drive and Cercis controller. Although the original focuser was quite serviceable for astroimaging, stepper drive and automatic focusing make life much easier. MoonLite has higher load capacity than the original focuser, it is also rotateable, and it looks nice too.

MonLite focuser is equipped with Cercis Astro FocusStar Controller. The controller is connected to a PC via USB port and is ASCOM compatible. I usually use it with FocusMax software for automatic focusing, which saves lots of time and nerves. Manual focusing for visual telescope use is also possible. Controller does the job nicely, although its USB connection can sometimes be problematic if it gets too cold (a heater solves the problem).

Here you can see my typical imaging setup with WO ZS105 ED telescope and SBIG ST-2000XM CCD camera on Losmandy GM-8 mount. On the telescope you can see Stellarvue 9X50mm finder. Both the telescope and the finder objectives are equipped with dew heaters. As you can se managing all the necessary cables is quite a challenge.